Madina Rival
email: madina.rival@cnam.fr

Are firms' lobbying strategies universal? Comparison of lobbying by French and UK firms

Keywords: lobbying, corporate political strategy, societal effects, data analysis, France and the UK

Lobbying public decision-makers is an increasingly widespread managerial practice, but has so far attracted little research attention in Europe. This article studies how it is put into practice as a strategy by French and UK firms. An empirical study examines 679 lobbying campaigns (also known as "political action"), that are grouped into categories and described using statistical data analysis techniques. The results highlight a pattern in the corporate lobbying phenomenon: five types of lobbying strategy (that can be described and illustrated) exist for French firms, and four for UK firms. The central theme of discussion is to what extent firms'political strategies are universal or country specific. Tentative explanations can be put forward: implementation of lobbying strategies appears to depend on the type of issues addressed (which could be universal), but also on the country's political environment (which could be country specific). The study shows the interdependent influence of human resources, economic structures and the political environment (laws and the role of the state) on firms' lobbying strategies.

Introduction

"The battlefield has now spilt over into the political arena, where firms are fighting to get decisions that might give them a competitive edge." (Reich, 2008, p.141). Bill Clinton's former Secretary of State, now a professor of public policy, devotes a whole chapter of the six in his latest book to the importance of lobbying by firms in the US, and also in Europe. The number of lobbyists assigned to the "climate law" in Washington, for example, is estimated at 2,810 (the equivalent of $90 million and 28 lobbyists for each of the senators central to the battle). i The front page headline of the French newspaper Le Monde on May 20, 2009 read: "Lobbying firms hope to benefit from the new Parliamentary rights" ii .

There are many ways for a firm to influence a public decision through what we shall call political strategies (American-style) or lobbying (the term more often used in Europe). In the US, lobbying is just one of many tactics to influence public decisions by passing on specific information. The term "lobbying" was coined in the US by General Grant; after a fire at the White House, he had moved into a hotel where the lobby was always full of pressure groups.

In Europe, the term refers to firms' overall political strategies.

Lobbying is a central, and rarely-studied (especially in Europe) component of "non-market strategies"(Baron 1995), which together with "product-oriented"' strategies form the overall strategy. Lobbyists are growing in number, including in France (a country where representation of private interests is not traditionally perceived positively). This is why both strategy researchers and lobbying practitioners (in-house managers or specialist firms) are interested in a clearer description of practices. The central question in this article is thus: are there recurring types of corporate lobbying strategies (as there are for general strategies, for example)? The objective of this research is to define a typology of lobbying strategies implemented by French or UK firms and then to discuss to what extent firms'political strategies are universal or country specific. France and the UK offer very different environments for lobbying. Comparison of practices in the two countries serves as a starting point for analysis of firms' chosen lobbying strategies.

The first section presents the relevant body of literature: This is not without its difficulties, as the body of research on "lobbying strategies" is relatively small. For a clearer definition of our object of research in management sciences, it is thus useful to take in more fundamental studies on interest groups found in the political science, economics and sociology (and societal effects approach) literature.

The second section presents the method and materials used: Data analysis (multiple correspondence analysis and classification using SPAD) is applied to a base of 679 lobbying campaigns by UK and French companies. These data are collected from the press and analysed using a grid drawn from the literature.

The third section presents the results and the knowledge produced: There are indeed "typical" lobbying strategies (or political strategies) that are used by French and UK firms.

Based on the sample observed, a limited number of strategies can be described through several variables: five in France, and four in the UK. Each of these strategies is illustrated by a real-life case drawn from the sample.

The fourth section discusses the results and concludes: The strategies characteristic of each type of lobbying depend on the nature of the issue addressed (which could be universal). The type of lobbying chosen, however, depends on the firm's national environment (which could be country specific). This study shows the interdependent influence of organizational resources, economic structures and the political environment (laws and the role of the state) on firms' lobbying strategies.

Lobbying: a complex corporate strategy

Analysis of the literature on lobbying presents our first obstacle, as there is very little research on firms' lobbying strategies (if journalistic-type factual analyses are excluded). Interest groups are studied in more general but fundamental research in other disciplines such as political science, economics and sociology, which will be useful to make a cross country comparison 1.1. A cross-disciplinary approach to compare firms' political strategies across countries In political science, [START_REF] Mény | Politique comparée, les démocraties[END_REF] first distinguish the interest group from other groups in society (such as family, tribe or race) by its interaction -in any form -with State institutions and the parties engaged in the fight to gain and exercise power. They then differentiate between lobbies and interest groups in general. Interest groups do not only act through pressure, and may be part of the State. Lobbies are generally considered as pressure groups, in contrast to the term's more restrictive original meaning, which simply referred to people in the corridors of US Congress.

Economic theories of lobbying are to be found in the "political market" concept defended primarily by Stigler and Becker. Stigler (1975), for example, developed an economic theory of regulation, also known as the "capture theory" or "positive economics of regulation", which describes how interest groups and political actors make use of State regulatory resources and coercive power to orient laws and rules in directions that are favourable to them. From the open firm angle, Baron (1995) gives a more detailed definition of a "non market environment": this encompasses the social, political and legal forces that are exogenous to the market but interact with private interests. Baron thus highlights the activity of firms that respond to the public sphere's influence on their environment.

For the sociology of organizations, the focus is on explaining how lobbying comes to be organized differently in two different countries, and "to point out the sources of additional variety" (Maurice, Sorge, Warner, 1980, p 80). The societal effects approach could help us in this, since it considers societies as recombination of global and local processes [START_REF] Sorge | The Global and the Local[END_REF].

New micro and macro influences on lobbying strategies should be looked for: the political environment, for instance, but also other factors such as organizational resources, industrial structures or the role of the state. 1.2. A more specific literature on organisations' political strategies to build a descriptive grid of lobbying actions Political lobbying activity by US firms at federal level developed enormously in the 1970s [START_REF] Vogel | The study of business and politics[END_REF]. It was in this context and this period that the field of research known as corporate political strategy emerged, and it is in that field that this article belongs.

Three studies draw up an overview of lobbying activities.

The oldest reference on the subject remains the study by [START_REF] Epstein | The Corporation in American Politics[END_REF], who defines five essential features of the organisation and practical implementation of lobbying: the objectives chosen, the body in charge of implementation, the available resources, the management's attitude to lobbying and the chosen tactics for political action. More recently, Hillman and Hitt published an essential article in 1999 in the Academy of Management Review presenting corporate political strategy as the result of a series of three decisions, each encompassing two or three modalities: the general approach to political action (measurement of the depth and continuity of communication between the firm and public decision-makers); the level of participation (often referred to in the literature on political strategy); and the generic strategy.

The model is most detailed on this last point, since Hillman and Hitt propose three generic strategies (information, financial incentive, and constituency building) broken down into subsets of tactics that are strongly marked by US practices. Drawing on the existing literature, they propose a range of variables that can affect corporate lobbying strategy. These variables can be grouped into two categories: factors related to the firm (firm size, industry sector, degree of diversification, multinationalisation of activities, nature of resources) and factors of an institutional nature specific to each country (governmental regulation, national preferences for corporatism). In the end, the authors present a decision tree that theoretically leads to twelve political strategies that could be used by a firm, but the article says nothing about operational considerations. Since this pivotal article was published, there have been few new general studies of corporate political strategy. We can however cite the work of [START_REF] Tian | The Determinants of Corporate Political Strategy in Chinese Transition[END_REF], which essentially makes two new contributions: it concerns Chinese firms that are rarely studied from this angle; and for the first time it proposes a quantitative treatment of a taxonomy of corporate lobbying strategy. However, the six-strategy typology (government involvement strategy, direct participation strategy, institution innovation strategy, prolocutor strategy, government association strategy and financial incentive strategy) is not explored in depth in the article. Above all, the empirical validation of this typology is highly questionable: although the authors apply statistical analysis to 201 questionnaires intended to define corporate political strategy, those questionnaires are administered to MBA students.

The other references in the "political strategies" corpus, whether of US or European origin, focus on precise points in lobbying campaigns. We shall present a brief overview and put them into perspective in the field of management sciences.

For [START_REF] Miles | Organizational Strategy: Structure and Process[END_REF], generally speaking, a firm can act as a "prospector" (implying the need for ex ante surveillance of the environment, and therefore strategic monitoring), a "defender" (through an ordered ex post reaction to a change in the environment), or an "analyst" (hybrid action). A practical analysis of these issues in relation to lobbying is proposed by [START_REF] Demil | Stratégie de pionnier et de suiveur : une application à un processus réglementaire[END_REF] in an empirical study of waste processing in the hospital sector, leading to the conclusion that no single strategy is the best. Also, according to [START_REF] Farnel | Le lobbying : stratégies et techniques d'intervention[END_REF], there are two fundamental strategic options for relations between the firm and the public authorities: "continuous" cooperation or the "ad hoc" approach. He argues that a continuous approach allows the firm to build trusting relationships externally, and generates a learning effect internally for the parts of the firm concerned by the lobbying. However, this continuous approach would require greater investment of resources by the firm, which must be compared to the benefits derived. Next, the person or entity doing the lobbying may be an external firm [START_REF] Lamarque | Le lobbying[END_REF] or an agent internal to the firm, a unit that may be specialised in lobbying (Attarça, 1999) or not. This is a classic problem in organisational theory: in-house management versus outsourcing of lobbying activities. Each option has advantages and disadvantages that must be weighed up. For instance, setting up a specific in-house unit avoids conflicts of interest (or agency problems, to use the terminology of [START_REF] Jensen | Theory of the Firm, Managerial Behaviour, Agency Cost and Ownership Structure[END_REF]) and improves knowledge of the interests to defend, combined with resources that are permanent. But it requires considerable size and resources, and involves difficulties in hierarchical organisation. Engaging a lobbying firm, in contrast, gives the firm access to experienced lobbyists at a lower risk, but its interests may receive a less wholehearted defence, and conflicts of interest may arise, or even confidentiality problems regarding strategic corporate information. Lobbying can take the form of individual or collective (structured or unstructured) action. The choice between these two options is up to the firm, and its decision depends on the nature of the issue and the target, but also on its opportunities to join existing groups. In making its decision, the firm will evaluate the cost/benefit ratio. The expected benefits of collective action are of several natures: additional influence in negotiations and greater credibility, economies of scale, efficiency, competitivity, synergies, greater ability to fight individual opportunist political strategies. But there are also costs to be taken into consideration: the opportunity cost of an individual action that could have been beneficial for the firm but goes against the interests of the group, or occasionally an action contrary to the firm's interests but beneficial to the majority of lobbyists taken together; the cost of controlling the activities of other members. [START_REF] Mclaughlin | Corporate Lobbying in the European Community[END_REF], for example, demonstrated that the respective size of different members had an influence on these interest groups' capacity for action. [START_REF] Getz | Selecting Corporate Political Tactics[END_REF] also drew up a typology of forty-eight potential targets by cross-comparing four criteria: the target's origin (governmental or otherwise), its geographical level (international, national, regional, local), its function (executive, legislative, judicial), and the firm's access to this source (internal or external). Attarça (1999) distinguishes between the informational, relational, symbolic, organisational, economic and financial resources dedicated to lobbying. The table developed by [START_REF] Corrado | Media for Managers[END_REF] contrasts certain techniques: direct/indirect communication methods, relational/financial mode of influence. [START_REF] Jacomet | Les stratégies d'entreprise face aux politiques publiques : le lobbying des producteurs occidentaux et la politique commerciale internationale dans le textile habillement[END_REF] identifies two different types of lobbying strategy: "pressure" and "interaction". The pressure strategy depends on dominating or even capturing behaviour by the firm towards the public authorities (and other interest groups), whereas the interaction strategy emphasises "competition with other interest groups and a more balanced relationship with the public authorities, leaving room for trade-offs and compromises where necessary" (our own translation).

The method: a quantitative empirical study in France and the UK

As the first objective of this study is to present a typology of corporate lobbying strategies, we use a quantitative research design. Since collecting data on lobbying proved particularly difficult, we chose an original protocol that uses the press.

The data

Empirically, we wanted to get away from the US context which is practically the sole reference in lobbying research. This study looks instead at the European situation. We decided to carry out a quantitative study (such that any typical lobbying strategies identified could be generalised). Our study also compares two different countries (France and the UK) for a more potent interpretation of the lobbying strategies implemented by firms.

To identify lobbying campaigns by French and UK firms (the individuals studied), the press was clearly the only source likely to supply data in sufficient numbers for our intended quantitative analysis, because unlike Brussels and Washington, Paris had no register of lobbyists. Besides, this type of register contains no details on how political strategies are formulated. Finally, interviews with four lobbyists before beginning the study confirmed that the press was indeed a reflection, partial but realistic, of corporate lobbying situations. More specifically, the information on the lobbying cases studied was taken from systematic daily consultation of three key business newspapers: La Tribune and Les Echos in France, and the Financial Times in the UK. These publications were selected based on an exploratory study covering several months, carried out by a team of researchers at top French business school HEC (Nioche, 1998 and forthcoming). The information gathered from the press was manually double-coded, verified and complemented using other sources (chiefly websites, telephone interviews, and the Diane databases). We retained only facts describing existing lobbying campaigns, ignoring those describing intentions of lobbying. The analysis covered the year 2000 for UK and French firms (for the latter, it was extended backwards to 1995 due to the lack of complete data for a single year). 2000 was chosen because it was the key year for development of lobbying in EU and France (particularly high number of actions, laws, etc).

The final sample consists of 679 French and UK lobbying campaigns. For the purposes of this study, the "individual" is a lobbying campaign carried out by a firm on a given theme. Some firms may be involved in several lobbying campaigns at different times on different subjects, just as an ad hoc strategy can be adopted for different strategic areas of business.

Data analysis

A grid describing the corporate lobbying campaigns was constructed by comparison with the literature on "political strategies" referred to in 1.2 and an initial qualitative approach to field research. In an exploratory then confirmatory step, we interviewed four lobbyists twice iii : two lobbying managers from two large French groups (one working at national level, the other at European level), and two consultants from international lobbying firms. These interviewees are not representative, although they were selected in order to illustrate the diversity of the work of lobbyists represented in France by the Association Française des Cabinets de Lobbying (AFCL, since 1991) and the Association des responsables des Relations avec les Pouvoirs Publics en entreprise1 (ARPP, since 1987). The main aim was to gain substantial knowledge of the object studied (direct knowledge of the object, without going through the prism of theory) (Becker, 2002). This empirical approach enabled us to carry out an initial selection from the theoretical materials presented. We grouped the variables that were ultimately used into five themes: the first analyses the firm's general stance in its political environment, and the other four describe the components of a specific lobbying campaign.

Table 1 shows this analysis grid, which was then used to describe the lobbying campaigns observed during our study. Data analysis was carried out separately on lobbying campaigns by UK firms and French firms. Multiple correspondence analysis followed by classification reveals the existence of a limited number of political strategies in either case. Through analysis of the modalities of variables and the individuals associated with each class, each type of lobbying observed can be described. In the end, a "French model" and a "UK model" of lobbying emerge.

The results: French and UK lobbying strategies

Data analysis brought out the existence of a small number of standard lobbying strategies, evidenced statistically by classes. French firms tend to use five different types of strategies, and UK firms four. The data analysis shows that these lobbying typologies are not determined by the same variables, even though there are some similarities. For example, structuring of lobbying is central in UK firms but not French firms. Description of these lobbying strategies requires names in the same way as names are often given to generic diversification or refocusing strategies. The chosen terminology is as explicit as possible, but should not be allowed to mask the complexity of the variables that lie behind a geographically-oriented vocabulary.

A "dispersed" French model of lobbying

The French firms studied use five lobbying strategies that are all very different from each other. We have called them "international lobbying" for class 3, "European lobbying" for class 1, "reactive national lobbying" for class 2, "proactive national lobbying" for class 5, and lastly "local lobbying" for class 4. Real-life cases from the sample illustrate each of these strategies. Class 3, comprising 88 individuals, covers international lobbying: an international, "nonpolitical" target that takes decisions with a specific scope will tend to be contacted directly for a cause of public interest. The public interest aspect is thus more important internationally than at lower geographical levels (private interest no longer seems to come into the equation).

The public decision-maker taking specific decisions will tend to be "non-political" (such as the WTO, for example). It will be more receptive to political action taken directly by firms, maybe because of the existence of ad hoc units in the target international organisations. Such organisations are strongly influenced by American culture, which assigns lobbyists a proactive role.

A French example of international lobbying:

Hyparlo's lobbying of the WTO "There must be something to counterbalance globalisation. Especially in agriculture, which must provide a minimum of food safety for everyone and enough information for consumers. At least, that's the position of the The lobbying campaigns in classes 2 and 5 essentially take place at national level. In both cases, the target of the lobbying makes decisions for general application. Other variables (initially less significant) must be analysed to differentiate these two styles of political action.

Class 2 (215 individuals) represents "reactive national lobbying" while class 5 (79 individuals) defines "proactive national lobbying". A wide range of political action is possible at national level, and this is why firms can consider two types of strategy. In "reactive" lobbying, the company is less involved and must select single issues when it wishes to have its voice heard by influential public decision-makers. In most cases the aim is to gain protection against a general decision (law) so as to minimise the consequences of that decision for the firm. Such relations are a source of antagonism between the target and the lobbyist, who will therefore use pressure to advance his aims. However, lobbying at national level can be a strategy in its own right ("proactive action") characterised by ongoing contacts with the public authorities. In such cases the firm monitors the regulations (active attitude), and this leads to a desire for cooperation with the target. Lobbying in this context is considered as a comparative advantage in seeking to maximise gains, in a number of fields. Class 4 and its 32 individuals defines "local lobbying": with a generally local target of a legislative nature, the firm applies a dynamic (active) general policy for an important cause involving several issues and lobbying is conducted in interaction with public decision-makers.

There are many local political actors in France, from the mayor to the county councillor to the regional councillor. Members of the national parliament also play a role at this level, as they are allowed to occupy both a national and local function (or even three functions if one is in a town of less than 3,500 inhabitants). With their close local contacts, they are more in touch with entrepreneurs, who may have an active lobbying attitude. Firms can thus put forward many issues in interaction with public decisions.

A French example of local lobbying:

Sabaté Diosos' lobbying of regional councillors "Who would believe that a cork is a high-tech product and its market is measured in billions of units? In Céret, a village nestling in two hills in French Catalonia between Perpignan and the Spanish border, Augustin Sabaté, chief executive of Sabaté, proves it with the revolutionary new cork Altec. (..) Augustin Sabaté has even set up the "G16", a lobby of 16 firms. "This group means we can put our position to the regional councillors" says one of its members, Christine Coste, manager of Coste fils, which makes packaging and has 30 employees." La Tribune, November 15, 1995)

(

A UK model of "concentrated" lobbying

As previously, each class derived from the data analysis corresponds to a type of lobbying strategy (illustrated by an example from the sample). International and local lobbying strategies are no longer observed in the case of UK firms. We shall return to this point in the discussion. European lobbying is observed, with similar features to the French model, but strategies at national level are partly divergent, and will be described below.

Table 3. Model of UK firms' lobbying strategies

Unstructured national lobbying (class 3) comprises approximately a quarter of all

individuals. This corresponds to a proactive, direct one-off action using pressure. It is the only type of lobbying to involve campaigns with a financial mode of influence, emphasising the public interest of a problem and aimed at a non-political target.

A UK example of unstructured national lobbying BOC's lobbying of the British government

"The government is considering significant concessions on the climate change levy following fierce lobbying by industrial companies that were excluded from a discount deal struck in December. (…) One of the fieriest campaigns is being waged by the industrial gas manufacturers BOC, Air Products and Messer Griesheim, which say the levy will cost them one 12.5 m a year. Much will be passed on to customers. Hugh Mortimer, commercial manager for utilities at BOC Gases said the company was one of the UK's five biggest users of electricity. It wants exemption from the levy, which the government conceded last year, for primary aluminium smelting and chlor-alkali production." (Financial Times, February 18, 2000) Ultimately, it is possible to separate structured national lobbying into two subgroups of relatively comparable size, corresponding to classes 2 and 4. Apart from the logic of action and the geographical level of the target, these strategies have in common the expected result of a maximised gain, frequency of contacts with ad hoc public authorities, a general decisionmaking target in 100% of cases (explained by the national level of the target) and an issue of private interest. In all other lobbying variables, however, they differ.

Proactive lobbying (class 2) appears to be based more on an active attitude, run over a long period and call on external professionals. Also, the focus on a single issue appears to be a factor of efficiency. In contrast, reactive lobbying (class 4) takes place in response to a public decision that has already been made (passive attitude) and is organised in-house, sometimes without focusing on a particular objective.

A UK example of proactive structured national lobbying Eidos Interactive's lobbying of the UK government "Last year the European Leisure Software Publishers Association's unit carried out nearly 1,000 raids across Britain with the police and trading standards. (…) ELSPA is lobbying the government to follow the example of Sweden by introducing a levy on blank CDs, DVDs, CD writers and DVD writers to reduce the profits of pirates. Under ELSPA's proposals, the funds would be channelled directly to enforcement agencies to help them fight piracy." (Financial Times, November 7, 2000)

A UK example of reactive structured national lobbying Corus' lobbying of the UK government "The chancellor's proposals to revive inner cities will address a range of small problems but are too limited in scale to provide a significant boost to the construction and house building sectors. That was the initial reaction from companies and organizations in the building and property fields, although they said more information was b. National reactive and proactive lobbying strategies exist too in both countries and they reflect most of time political resources balance of the firm.

a. At European level, the Commission is responsible under the EC treaty for formulating public policies in the European Union, while the European Parliament appears to be a weaker institution. The European Commission will therefore be the target of first choice for lobbyists concerned with European issues. Similar to international level, the informational, economic and financial resources of a single firm appear to be insufficient due to the supranational scale of the issues covered. This is why Europe 1 used a structured, specialised collective body, the European Broadcasting Union, as an intermediary for its lobbying campaign. Also, the complexity (and the relative recency) of European decision-making processes influences the choice of the firm's political and organisational resources. It generally drives the firm to call on the services of a professional external lobbyist (in more than 90% of cases for UK firms), and also to focus on a single issue (e. b. At national level, formal and informal recognition of lobbying differs from one country to the next. French and British specificities are discussed below. However, modes of corporate action will vary according to the political resources firms are able to mobilise in a given country. In the national context, the "proactive" and "reactive" approaches appear in very general terms to separate lobbyists with extensive political resources from lobbyists with insufficient political resources. In the UK's Eidos Interactive case, for example, the European Leisure Software Publisher Association covers all operators in the sector, like Paris Europlace in the French Société Générale case. In contrast, the Construction Products Association that represents the UK firm Corus is just one of many representative groups in the sector, with competitors such as the House Builders Association, the Construction Confederation and the Builders Merchants Federation. Likewise, the French firm Canal Plus started up an individual campaign although many other interests were involved (advertisers and public service channels for instance). But not all unstructured campaigns are "reactive"; this study identifies a different "unstructured national" type of lobbying that is more widespread in the UK. It is a deliberately-chosen style of action displaying a proactive general policy by the lobbyist, contrary to the "reactive national" lobbying strategy. A firm acting alone or collectively in an unstructured way will perhaps have smaller organisational, symbolic and relational resources. Lack of organisational resources limits continuous action. When a firm is involved in "unstructured national" lobbying, on the other hand, it may hope to increase its symbolic resources by references to the public interest, and develop its relational resources by putting pressure on its target. In addition, the firms that opt for this type of action are certainly those that also have extensive informational, financial and economic resources (especially large firms, such as BOC in the UK model). They are thus well-placed to apply a proactive policy, and replace the relational mode of influence by a financial mode of influence. 4.2. The type of lobbying chosen depends on the firm's national environment, i.e. its economic and political environment.

Before this study, in a similar vein, [START_REF] Keim | International variation in the business government interface: institutionnal and oragnizational considerations[END_REF] referred to the existence of international differentiation in relations between firms and public decision-makers, comparing the parliamentary systems in France, Japan and Germany with the situation in the US. Here, from a brief overview of the situations in France and the UK, we see that the two national frameworks do not carry the same threats or the same opportunities for lobbying firms. c. French firms' international lobbying strategies could be triggered by a specific economic environment.

a. Both formally and informally, the situation for lobbying is more favourable in the UK, where it is recognised by national institutions and considered legitimate in practice, which is not the case in France. The first consequence of this state of affairs can be measured by the annual number of corporate lobbying campaigns in each of the two countries: it is twice as high in the UK as in France (169 in the UK in 2000, compared to an annual average of 85 in France between 1995 and 2000). There is also coherence between the formal and informal frameworks for lobbying in the UK and Europe (institutional recognition and legitimacy). This encourages UK firms to specialise in these two types of lobbying (half of the campaigns are at European level and half at national level). National lobbyists develop skills in the UK that they can then use effectively in respect of European public decision-makers. Furthermore, standardisation of lobbying styles (limited to two levels) reduces the cost of campaigns. French firms, in contrast, do not give priority to European-level lobbying (less than 20% of the total). At national level, the specific situation of UK lobbying again explains why UK firms choose three types of lobbying strategies whereas French firms focus essentially on "reactive national" lobbying. First, unstructured national lobbying is only possible when there is formal or informal recognition of lobbyists (i.e. in the UK). When no regulation exists, only the "strongest" and "most experienced" (collective actors) are likely to achieve their aims. Next, French lobbyists, who have smaller political resources, make more use of "reactive national" lobbying (42% compared to 15% of proactive campaigns), while structured national campaigns by UK firms are evenly distributed between "proactive national" and "reactive national" lobbying. b. Unlike the situation in France, the UK environment more generally provides little incentive for firms to take local or international action. At institutional level, the essential difference between the two countries does not lie in the political systems (one semi-presidential and the other parliamentary), since over the period studied the practice of political "cohabitation" in France (when the President and government are from different political parties) reduces executive power and brings the country closer to a parliamentary system. Nonetheless, it is important to note the growing concentration of local authorities in the UK: their number has been divided by three since 1974 and there are only two levels of local government (County and District).

As a result, the small constituencies and local contacts with public decision-makers that are advantages in local lobbying do not exist in the UK. In contrast, the three local government levels to be found in France (municipality, département -roughly equivalent to a county, and region) all provide opportunities for firms that might be involved in local lobbying. France has 8,704 municipalities, 95 provinces and 20 regions, compared to just 490 local administration units in the UK. This fragmentation of French territory complicates management of local issues by the State and reinforces the value of local lobbying for French firms. Also, the geographical and therefore cultural proximity often observed (the Sabaté Diosos case concerns the interests of the Catalan region around Perpignan) increases the lobbyist's relational and symbolic resources. This makes lobbying easier: it can be proactive and concern several issues at once, in interaction with public decision-makers. c. From an economic standpoint, the French State's involvement in the business world, especially the existence of elite networks (especially from the haute école vocational university system), also helps to explain the lower number of lobbying campaigns observed each year in France: the configuration of the French political economy is more auspicious for informal contacts between firms and public decision-makers. As this study only examines lobbying officialised by media coverage, it cannot take this informal type of lobbying into consideration. Looking at the economic context of our sample, in the year 2000 UK firms were less open to international trade (because the pound sterling was very strong at the time), and this could partly explain their lower interest in international issues. France, in contrast, was a net exporter over the period 1995-2000. The French firms concerned thus sought to defend their interests, especially in respect of the World Trade Organisation. International lobbying strategies ultimately accounted for only 17% of campaigns in the French model. At international level, indeed, symbolic and relational resources can be mobilised more easily. The WTO officially recognises lobbying, legitimising it and defining it in official texts. It has, for example, set up a dynamic programme for relations with NGOs representing a range of trade-related interests. When the Marrakech agreement was adopted after the Uruguay round of negotiations, the ministers decided to make express reference to relations between the WTO and non-governmental organizations (article V-2). On July 18, 1996, the General Council defined the framework for development of these relations, issuing a set of guidelines (WT/L/162) that "recognize the role NGOs can play to increase the awareness of the public in respect of WTO activities and agree in this regard to improve transparency and develop communication with NGO". In our case, the FCD adapted to the NGO framework, adopting a discourse referring to general public interest (consumer health and information). It was thus able to use a direct method of communication with its target.

In conclusion, this article offers an empirical model of the existence of a small number of lobbying styles used by firms in France and the UK and the beginning of an answer about universality or country specificity of those strategies. Our study is based on quantitative information. The results of data analysis (multiple correspondence analysis and classification) highlight patterns in corporate lobbying, showing similarities but also differences between French and UK practices. This suggests that the strategies typical of each type of lobbying depend on the nature of the issue to be resolved. The type of lobbying chosen, however, appears to depend on the firm's national environment. This shows the interdependent influence of organizational resources, economic structures and the political environment (laws and the role of the state) on firms' lobbying strategies. Thus, societal effects theory could be applied to firms' political strategies which are at the same time global and local.

Our results do have limitations. At this stage they remain hypotheses that require subsequent validation, for example by more detailed case studies of certain corporate lobbying campaigns. Our conjectures are essentially based on a rational, efficient approach to lobbying. However, this general theoretical framework can be challenged. Might there not be inadequacies in decision-making (bounded rationality) or in application of lobbying (agency problems) within the firms themselves? Also, at this stage of analysis, the question of the performance of different corporate lobbying strategies is not addressed, although admittedly their performance is difficult to measure.

Bibliography

  Percentages are calculated in relation to the total number of individuals studied -European lobbying (Class 1) 48.5% -Unstructured national lobbying (Class 3) 22.5% -Reactive structured national lobbying (Class 4) 17.2% -Proactive structured national lobbying (Class 2) 11.8% At national level, the first distinction to emerge is between the unstructured lobbying strategies (whether individual or collective) in class 3 and the structured (and therefore collective) strategies in classes 2 and 4.

  g. World Cup football broadcasting rights) over a long period of time. The regulatory framework for EU lobbying is based on the transparency principle (Transparency in the Community, Official Journal of the European Community, C166 1993). More directly, the Commission published an important paper on December 2, 1992 entitled "An open and structured dialogue between the Commission and interest groups" (Official Journal of the European Community, C 63 5.3.93). While this framework does not give lobbyists a pre-eminent place, it recognises and legitimises their existence. This accordingly broadens their relational and symbolic resources, enabling firms to adopt a general ongoing and anticipatory lobbying policy, which receives a more favourable reception from the European target when it emphasises a public interest aspect (cf Europe 1 and the audience for World Cup football).

  Consequently, French and UK firms will not always use the same types of lobbying strategies. Three examples of this local influence on lobbying strategies can be found in our results: a. The choice of British firms concerning European lobbying and unstructured lobbying strategies is linked to the lobbying status in the UK.b. The findings of local lobbying for French firms can be explained by the number of local government levels in France.

  Attarça M. (1999), « Une introduction au concept de « stratégie politique d'entreprise » », Thèse de doctorat de gestion, Ecole des Hautes études Commerciales de Paris. Baron D.P. (1995), Business and its Environment, Prentice Hall, Upper Saddle River. Becker H.S. (2002), Les ficelles du métier : Conduire sa recherché en sciences sociales. Paris, La découverte.

Table 1 . Analysis grid for lobbying campaigns studied in this article

 1 After establishing frequency tables of data, data analysis techniques (multiple correspondence analysis and classification) were implemented in SPAD to model the political behaviour of the lobbying firms included in the constructed database. These data analysis techniques are appropriate to describe explanatory models with multiple qualitative variables related to exogenous or endogenous factors. By minimising intra-class variance while maximising interclass variance, this statistical process finally led to definition of classes of homogeneous individuals within the sample. Each class represents a particular type of lobbying strategy.

	Field	Variable	Mode
	Firm's general lobbying policy	General attitude to the public	active,
		authorities	anticipatory,
			passive
		Frequency of relations with the public	continuous,
		authorities	ad hoc

Table 2 . Model of French firms' lobbying strategies

 2

	Percentages are calculated in relation to the total number of individuals studied
	-International lobbying (Class 3) : 17.25%
	-European lobbying (Class 1) : 18.82%
	-Reactive national lobbying (Class 2) : 42.16%
	-Proactive national lobbying (Class 5) :15.49%
	-Local lobbying (Class 4) : 6.27%

example of European lobbying: Europe 1's lobbying of the European Commission

  Fédération des entreprises du commerce et de la distribution iv (FCD), which yesterday presented the issues at

stake in the next round of negotiations in international trade, the Millenium Round due to open in Seattle in the US on November 30. (…) These positions will be relayed to the WTO and Millennium Round negotiators by Eurocommerce, the European retailers' lobbying organisation."

(Les Echos, November 10, 1999)

Class 1, which comprises 96 individuals, represents "European lobbying": this involves a European target and relates to a cause of both private and public interest, without any precise identification of the person behind the lobbying. There is little information on "European lobbying" except that it is more open to public interests than national and local lobbying due to the supranational dimension of the action. Also, the lack of response concerning the choice of lobbyist may be explained by a certain lack of transparency in action by French firms.

A French

"With Kirch having just bought the rights to show the next two football World Cups for 11.2 billion francs, the inflation in TV rights for sports events is worrying public European operators. (…) "We are going to undertake a lobbying campaign so that the general public has access to World Cup matches" declares the EBU

[European Broadcasting Union]

. It has a weapon to serve its aim: the European Television without frontiers directive."

(Les Echos, July 30, 1998)

A French example of reactive national lobbying: Canal Plus' lobbying of the French government

"With his awareness raised by TF1 and M6's recent criticisms of France Télévision's commercial policy, the Minister of the Budget and Communication Nicolas Sarkozy is due to announce his position today on the thorny question of France 3's advertising excesses (…) Meanwhile, the encrypted channel Canal Plus, whose advertising breaks are no longer than three minutes, also made its own contribution to the debate by publishing the results of a survey carried out with the Vidéopost institute." (Les Echos, February 6, 1995)

A French example of proactive national lobbying: Société Générale's lobbying of French public decision-makers

"With less than a year to go before the introduction of the Euro, Paris Europlace, which is responsible for promoting the Parisian finance markets in other countries and lobbying the authorities to adapt the Paris market to the international competitive environment, has its work cut out. (..) For the chairman of the association's orientation committee, one of the priorities is fiscal realignment of the Paris market with the other European markets as regards taxation of both operators and establishments."

(Les Echos, March 26, 1997)

The names translate respectively as "French Association of Lobbying Firms" and "Association of firms' managers of relations with the public authorities".

still needed on questions including how the government would define "disadvantaged areas". (…) The Construction Products Association said its members faced growing competition in south-east England from continental European suppliers, which were now importing even bulky products such as bricks into the UK." (Financial Times, November 11, 2000)

Discussion and conclusion

This study draws up a typology of French and UK firms' lobbying strategies. More light can be thrown on the characterisation of these types of lobbying and comparison of results for France and the UK by a return to the initial theoretical framework of analysis. The results show the interdependent influence of organizational resources, economic structures and the political environment (laws and the role of the state) on firms' lobbying strategies.


Zoltán Kiss
email: zkiss@amgen.com

Steven Elliott

Kinga Jedynasty

Vladimír Tesar

János Szegedi

Discovery and basic pharmacology of erythropoiesis-stimulating agents (ESAs), including the hyperglycosylated ESA, darbepoetin alfa: an update of the rationale and clinical impact

Keywords: Red blood cell (RBC), Biological activity, Erythropoietin (EPO), Erythropoiesis-stimulating agent (ESA), Recombinant human erythropoietin (rHuEpo), Carbohydrate, Sialic acid, Darbepoetin alfa, Glycoengineering, Biosimilar, FOB

    Discovery and basic pharmacology of erythropoiesis-stimulating agents (ESAs), including the hyperglycosylated ESA, darbepoetin alfa: an update of the rationale and clinical impact

Introduction

Red blood cells (RBCs) represent >99% of total circulating blood cells (∼5×10 12 per liter, or 2.5×10 13 total) and typically occupy approximately 40-45% of the total blood volume. Hemoglobin (Hb), the predominant molecule that transports oxygen (O 2 ) from the lungs to tissues, constitutes 99% of the cytosolic protein in mature RBCs [START_REF] Hebbel | Pathobiology of heme interaction with the erythrocyte membrane[END_REF]. This large amount of Hb is consistent with the requirement for a large O 2 transport capacity that must support the considerable consumption of O 2 in tissues. The lifespan of an RBC is approximately 100-120 days, indicating that ∼1% of the total must be replaced each day. Replacing this number of cells requires a prodigious RBC production rate. This means creation of >10 10 new RBCs per hour, which exactly matches the rate of RBCs disappearance. Should the loss of RBCs exceed their production, anemia can occur.

Prior to the discovery of recombinant human erythropoietin (rHuEPO), anemic patients with chronic kidney disease were treated with RBC transfusions with all its disadvantages. The major clinical benefits of rHuEPO were treatment of anemia and avoidance or minimization of blood transfusion and its associated risks. rHuEPO is administered by injection three times a week, which aligns well for dialysis patients receiving thrice weekly treatments; however, for chronic kidney disease (CKD) patients not on dialysis, this dosing schedule may introduce hardship, as patients often need to visit the clinic solely for the purpose of erythropoiesis-stimulating agent (ESA) administration. Prolonging the dosing interval for ESAs could be addressed by an increase in dose. Another possibility was to create a new rHuEpo glycosylation analog that had a longer serum half-life [START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF]. Research into this possibility resulted in the discovery of a novel ESA, Aranesp® (darbepoetin alfa), which became available for anemic patients at the start of this decade. The aim of this paper is to summarize the discovery and development of recombinant rHuEPO and present the characteristics of ESAs and results of current ESA research, particularly focusing on darbepoetin alfa.

Erythropoietin and erythropoiesis

Details on the early history of erythropoietin and erythropoiesis, including the discovery of darbepoetin alfa and its properties, has been described in earlier work [START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF][START_REF] Elliott | Cancer drug discovery and development hematopoietic growth factors in oncology: basic science and clinical therapeutics, 6 chapter, Erythropoietic factors-Clinical pharmacology and pharmacokinetics[END_REF][START_REF] Erslev | Humoral regulation of red cell production[END_REF][START_REF] Miyake | Purification of human erythropoietin[END_REF]. Therefore, this paper describes the similarities and differences in the various ESAs, as well as their functional properties, with a focus on darbepoetin alfa . It was not until the 1980s that researchers from Amgen (led by Lin) isolated the human EPO gene [START_REF] Lin | Cloning and expression of the human erythropoietin gene[END_REF]. Cloning the EPO gene was a breakthrough in treatment of anemia. Endogenous and recombinant erythropoietin both consist of a single polypeptide chain backbone [START_REF] Lai | Structural characterization of human erythropoietin[END_REF] composed of 165 amino acids (Fig. 1). The structure of rHuEPO is a compact globular bundle, which contains four alfa helices [START_REF] Syed | Efficiency of signalling through cytokine receptors depends critically on receptor orientation[END_REF].

Endogenous EPO production in adult humans occurs primarily in interstitial kidney cells. However EPO can also be produced in smaller amounts in the liver. Recent reports suggest EPO may also be expressed by cells of the central nervous system. Whereas reports of EPO expression elsewhere have been suggested, the reagents and methodologies associated with this work are of insufficient sensitivity and specificity to draw valid conclusions. Hypoxia results in increased EPO gene transcription through an increase in amount of a hypoxia -inducible factor (HIF) [START_REF] Jiang | Dimerization, DNA binding and transactivation properties of hypoxia-inducible factor 1[END_REF]. HIF binds to a hypoxia-responsive element located adjacent to the coding region of the EPO gene, resulting in increased gene transcription. As a consequence of tissue hypoxia, the EPO concentration in serum can increase up to 100-1,000-fold. Following synthesis of the protein portion of the molecule, posttranslational carbohydrate addition (glycosylation) can occur and in mammalian cells, there is further maturation into complex carbohydrates. Endogenous EPO and rHuEPO (such as epoetin alfa) contain three specific N-linked glycosylation sites (Asn24, Asn38, and Asn83) and one O-linked glycosylation site (Ser126). rHuEPO has four carbohydrate chains attached to these sites representing approximately 40% of total hormone mass [START_REF] Davis | Characterization of recombinant human erythropoietin produced in Chinese hamster ovary cells[END_REF].

The correctly folded erythropoietin molecule has two erythropoietin-receptor-binding sites with high and low affinities [START_REF] Elliott | Mapping of active site of recombinant human erythropoietin[END_REF]. EPOR (erythropoietin receptor), which is found on the surface of erythroid precursor cells, is a cell-Fig. 1 Amino acid sequence of human erythropoietin (EPO) with glycosylation at three specific asparagines residues (Asn24, Asn34, and Asn83) and one serine residue (Ser126) [START_REF] Elliott | Cancer drug discovery and development hematopoietic growth factors in oncology: basic science and clinical therapeutics, 6 chapter, Erythropoietic factors-Clinical pharmacology and pharmacokinetics[END_REF] membrane-bound protein that is activated when one EPO molecule binds to two receptors in a process called homodimerization [START_REF] Syed | Efficiency of signalling through cytokine receptors depends critically on receptor orientation[END_REF][START_REF] Elliott | Mapping of active site of recombinant human erythropoietin[END_REF][START_REF] Watowich | Activation of erythropoietin signaling by receptor dimerization[END_REF]. When EPO receptors on erythroid precursor cells are activated by EPO, the cells can be stimulated to survive, proliferate, and differentiate into RBCs.

Under certain conditions, such as when individuals descended from high altitude, the RBC mass decreased by approximately 10-15% over 7-10 days. This fact led to the proposal that EPO regulated not only production of RBCs but also their survival through an EPO-dependent physiologic down-regulation of RBC mass called neocytolysis [START_REF] Alfrey | Implications of neocytolysis for optimal management of anaemia in chronic kidney disease[END_REF]. However, RBCs lack EPO receptors, suggesting the mechanism by which RBC number declined must be indirect. One possibility was that RBCs were eliminated from the circulation with the help of the reticuloendothelial system (RES) involving EPO receptors on vascular endothelium or on phagocytes. Endothelial cells were recently shown to have undetectable levels of functional EPOR [START_REF] Sinclair | Functional erythropoietin receptor is undetectable in endothelial, cardiac, neuronal and renal cells[END_REF], raising questions about this mechanism. A more likely possibility is that RBC lifespan is impacted by oxidative damage that is increased when individuals with reticulocytosis due to adaptation to high altitude descend to lower altitude where increased oxygen could result in increased RBC destruction. Consistent with this proposal, rats exposed to hyperoxia had increased destruction of RBCs [START_REF] Landaw | Effects of hyperoxia on red blood cell survival in the normal rat[END_REF], as did human astronauts exposed to hyperoxia in space flight [START_REF] Fisher | Red blood cell mass and plasma volume changes in manned space flight[END_REF][START_REF] Berry | Preliminary clinical report of the medical aspects of Apollos VII and VIII[END_REF]. A mechanism by which oxidative damage may be regulated has recently been described. Forkhead box O3 (FOXO3a) is expressed during erythroid differentiation and reportedly plays an important role in RBC survival by inducing antioxidative proteins such as catalase, superoxide dismutase, growth arrest, and DNA damage-inducible 45 (GADD45) [START_REF] Hattangadi | Regulation of erythrocyte lifespan: do reactive oxygen species set the clock?[END_REF][START_REF] Marinkovic | Foxo3 is required for the regulation of oxidative stress in erythropoiesis[END_REF]. Because expression of FOXO3a, and by necessity, its downstream targets, require nuclear DNA, RBCs that have no nucleus become dependent on the antioxidative proteins made earlier.

Nonhematopoietic effects of erythropoietin

Recent results on possible nonerythropoietic effects of ESAs drew the attention of the scientific community. The possibility was supported by genetic studies in which EPO and EPOR knock-out mice presented with abnormal brain, cardiac, and blood-vessel development, suggesting that EPO and its receptor was involved in normal organ development [START_REF] Wu | Inactivation of erythropoietin leads to defects in cardiac morphogenesis[END_REF]. In other studies, ESA administration reduced the magnitude of ischemic lesions in the nervous system, myocardium, and kidney [START_REF] Erbayraktar | Erythropoietin is a multifunctional tissue-protective cytokine[END_REF]. For example, darbepoetin alfa reportedly had a protective effect on podocytes and reduced apoptosis in the kidney [START_REF] Logar | Darbepoetin alfa protects podocytes from apoptosis in vitro and in vivo[END_REF]. In rats with puromycin-induced nephrotic syndrome, darbepoetin alfa administration could reduce proteinuria [START_REF] Eto | Podocyte protection by darbepoetin: preservation of the cytoskeleton and nephrin expression[END_REF]. In addition, ESAs were reported to induce signaling in cell lines made quiescent by serum starvation [START_REF] Jelkmann | The erythropoietin receptor in normal and cancer tissue[END_REF]. The notion was extended to include Epo receptors on endothelial and tumor cells and that addition of ESAs to patients might stimulate tumor growth [START_REF] Jelkmann | The erythropoietin receptor in normal and cancer tissue[END_REF]. The proposed mechanism was that EPO bound to EPO receptors expressed on nonhematopoietic and tumor cells, resulting in growth promotion and/or an antiapoptotic effect. However, we should be caution with this theory. In tumor rodent xenograft studies, there was no increased growth in the ESA arm [START_REF] Sinclair | Expression and function of erythropoietin receptors in tumors: implications for the use of erythropoiesis-stimulating agents in cancer patients[END_REF]. In addition, the clinical trial results were controversial because of baseline imbalances in some of the trials that favored the placebo arm [START_REF] Glaspy | Erythropoiesis-stimulating agents in oncology[END_REF].

The notion that EPO receptors were expressed on nonhematopoietic and tumor cells was based largely on Western immunoblotting or immunohistochemistry experiments using antibodies that were shown to be nonspecific [START_REF] Brown | Erythropoietin receptor expression in non-small cell lung carcinoma: a question of antibody specificity[END_REF][START_REF] Elliott | Anti-Epo receptor antibodies do not predict Epo receptor expression[END_REF]. In addition, there are other results inconsistent with the hypothesis. Mice that were engineered to express EPOR exclusively in hematopoietic cells showed normal size and development, with no effect on development of the vascular endothelium [START_REF] Suzuki | Erythroid-specific expression of the erythropoietin receptor rescued its null mutant mice from lethality[END_REF]. In experiments designed to detect EPOR-induced signaling in tumor cell lines, including those reported to respond to ESAs by others, no effect was detected [START_REF] Laugsch | Lack of functional erythropoietin receptors of cancer cell lines[END_REF]. More recently, a specific antibody to human EPOR was described [START_REF] Elliott | Identification of sensitive anti-erythropoietin receptor monoclonal antibody allows detection of low levels of EpoR in cells[END_REF], and its application to EPOR expression in nonhematopoietic cells from kidney and heart tissues and endothelium revealed low to undetectable levels of EPOR protein. In these same cell types, no detectable EPO induced signaling, and no consistent antiapoptotic effect of ESAs with in vitro cell cultures was observed [START_REF] Sinclair | Functional erythropoietin receptor is undetectable in endothelial, cardiac, neuronal and renal cells[END_REF]. In a study with >200 tumor cell lines, EPOR was detected in only a subset of the total, and many of the lines with undetectable EPOR protein included cell lines reported by others to respond to EPOR [START_REF] Swift | Analysis of cell surface erythropoietin receptor (EpoR) expression and function in human epithelial tumor tissues[END_REF]. In the tumor cell lines expressing the highest relative levels of EPOR, there was no detectable induction of Epo-induced signaling and no effect on cell viability detected due to knock-down of EPOR by transfection with EPOR small interfering RNA (siRNAs). A direct examination of tumor cell response to EPOR was also undertaken. In >150 live tumors from patient biopsies, no ESA-induced signaling was detected in disaggregated cells, whereas robust responses were readily detected in the same cells treated with a positivecontrol growth-factor cocktail [33].

It is not possible to completely reconcile all the reported results, suggesting other mechanisms may be at play. One possibility is that the increased iron metabolism needed to support ESA-induced erythropoiesis may reduce oxidative stress [START_REF] Katavetin | Antioxidative effects of erythropoietin[END_REF]. Alternatively, increases in oxygen delivery at elevated hematocrits or changes in heart rate or blood hemodynamics may also explain the benefit of ESAs in certain animal studies. Clearly, further research is required to define the precise mechanism.

rHuEPO and follow-on biologics/biosimilars

Endogenous EPO is a complex biological produced by specialized cells that are impacted by forces unique to the body, including a complex interaction of circulating growth factors, nutrients, and particular cell-cell interactions. Circulating Epo is then subject to differential clearance of the various glycoforms. It is not possible to duplicate these processes in a manufacturing setting, thus rHuEPO differs from endogenous EPO. These differences include posttranslational modifications as well as the type and amount of contaminants, such as fragments and aggregated forms. Changes in cell lines or even more changes in growth conditions or manufacturing processes can affect the final ESA product characteristics, including the microheterogeneity of glycoforms. Changes in glycosylation can impact functional activities, such as binding affinity for cognate ligands, signal transduction, cellular internalization, and resistance to proteolytic degradation; and physical properties such as stability and solubility. These can affect product quality as well as clearance, efficacy, and safety.

It is not possible for another manufacturer to match exactly the cell line or the manufacturing conditions and consequently the product profile of the innovator product. Therefore, rHuEPO ... products made by different manufacturers are not identical to each other. Because of these differences, the term "generic" is not used to describe rHuEpo molecules made by different manufacturers. Instead, the descriptors "follow-on biologics" (FOBs) in United States, and "biosimilars" in European Union are used [START_REF] Huub | Biosimilar therapeutics-what do we need to consider?[END_REF]. Epoetin alfa was the first commercialized rHuEPO (Epogen ® , Procrit ® , Eprex ® ) and used Chinese hamster ovary (CHO) cells in its manufacture. Other epoetins (biosimilars) followed with different Greek names, reflecting the different cell lines and manufacturing methods (Table 1). The second approved rHuEPO was epoetin beta (Recormon ® , Neorecormon ® ) and also used CHO cells in its manufacture. It, like other rHuEpo biosimilars, has the same amino acid sequence as epoetin alfa with some minor differences in the microheterogeneity in the attached carbohydrate. Epoetin delta used human fibrosarcoma (HT1080) cells in its manufacture, but as of December 2008 is no longer distributed. Epoetin omega, produced in baby hamster kidney cells (BHK), differed somewhat from epoetin alfa and beta in the glycosylation profile. Other ESA biosimilars are being introduced in the EU, such as epoetin zeta. However, there are inconsistencies in the naming convention, such as with Abseamed/Binacrit/Hexal, which is marketed as an epoetin alfa. rHuEPO FOBs are also manufactured and distributed in countries where less oversight on drug manufacturing results in significant product quality and structural differences from epoetins distributed in the USA and EU [START_REF] Schellekens | Follow-on biologics: Challenges of the 'next generation[END_REF][START_REF] Jelkmann | Efficacy of recombinant erythropoietins: is there unity of international units?[END_REF][START_REF] Park | Biochemical assessment of erythropoietin products from Asia versus US Epoetin alfa manufactured by Amgen[END_REF]. These ESAs can vary considerably from each other and from marketed epoetins manufactured in the USA and EU in labeling, drug content, and specific activity. Even though different ESAs can share the same Greek name, there may also be considerable lot-to-lot variability. There have been reports that some patients administered these ESAs have presented with antibody-mediated pure red cell aplasia. Because a patient's safety is always the first and foremost aspect in treatment, switching patients from one rHuEPO to another should be performed by skilled health care practitioners who take into account both long-term efficacy and safety issues.

Role of carbohydrate on EPO activity

The biological effect of EPO (stimulation of erythropoiesis) is controlled by the interaction of EPO with its receptor. This interaction involves direct contact of the protein portion of EPO with the protein portion of the EPO receptor. The affinity of EPO to EPOR (the concentration of EPO required for half-maximal binding) can affect the magnitude of binding and therefore magnitude of response at a given EPO concentration. However, other elements of EPO also affect the biophysical properties as well as the magnitude of the biological response. Attached carbohydrate on rHuEpo comprises approximately 40% of the mass of the molecule [START_REF] Lai | Structural characterization of human erythropoietin[END_REF]. Whereas differences in carbohydrate content of EPO can affect affinity to EPOR, carbohydrate also plays an important role in maintaining the molecule in circulation (clearance) [START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF]. In addition to its effect on clearance, the increased content of negatively charged carbohydrates can also increase solubility and decrease adhesive properties of protein. Thus, the carbohydrate may shield hydrophobic residues, reducing aggregation while protecting potential immunogenic surfaces from immune surveillance.

Carbohydrate made in mammalian cells and attached to proteins is composed of a mix of various sugar molecules joined together into complex chains. Individual chains on rHuEPO can differ from others in sugar content, size, and degree of branching. One of the sugars found on the ends of each branch of a carbohydrate chain is a negatively charged molecule, sialic acid. Because of the microheterogeneity in number of branches, EPO has a natural variation in charge due to variation in sialic acid content. The presence of up to four negatively charged sialic acids on each of the three N-linked carbohydrate chains and up to two sialic acids on the single O-linked carbohydrate chain results in up to 14 sialic acids on both endogenous and rHuEPO [START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF]. Endogenous EPO is differentiated from rHuEPO in that there is further charge modification due to addition of sulfate to the carbohydrate. About 3% of the carbohydrate chains on epoetin alfa contain sulfate, and the content is typically limited to one sulfate per chain. In contrast, endogenous EPO can be extensively sulfated, with as many as three sulfates per carbohydrate chain. Thus, endogenous EPO can be considerably more negative (acidic) than rHuEpo [START_REF] Strickland | Occurrence of sulfate on the N-linked oligosaccharides of human erythropoietin[END_REF][START_REF] Lasne | Detection of isoelectric profiles of erythropoietin in urine: Differentiation of natural and administered recombinant hormones[END_REF][START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF].

A research group [START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF] performed studies on purified fractions of rHuEPO that had defined numbers of sialic acids and observed a positive correlation between sialic acid content of rHuEPO and in-vivo-specific activity. There was a similar positive correlation between sialic acid content and serum half-life for those isoforms. On the other hand, molecules with increased sialic acid content had less affinity to EPOR [START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF] (Fig. 2). These results indicate that in the case of rHuEPO, a longer half-life is a stronger determinant of in-vivo-specific activity than affinity to EPOR. However, from the clinical point of view, a balanced proportion of these two parameters is important.

N-linked carbohydrate attachment points consist of welldefined three amino acid consensus sequences (Asn-Xxx-Ser/Thr), where Xxx could be any amino acid except proline [START_REF] Elliott | Structural requirements for additional N-linked carbohydrate on recombinant human erythropoietin[END_REF][START_REF] Delorme | Role of glycosylation on the secretion and biological activity of erythropoietin[END_REF]. In order to add additional carbohydrate chains to rHuEPO, the coding region of the EPO gene was altered so that new N-linked consensus sequences were present and that a cell expressing these modified genes Fig. 2 Serum clearance is the primary determinant of in vivo activity of erythropoietin isoform (from [START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF], with permission) would recognize the new carbohydrate attachment points in rHuEPO. Using in vitro mutagenesis, rHuEPO glycosylation analogs with varying numbers of N-linked carbohydrate chains were successfully constructed and became available for testing [START_REF] Elliott | Mapping of active site of recombinant human erythropoietin[END_REF][START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF]. Addition of one new carbohydrate chain increased approximately 1.6-fold the in-vivo-specific activity in rodents, and addition of two chains resulted in greater than twofold increase, as measured by the exhypoxic polycythemic mouse bioassay [START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF]. In contrast, when one N-linked chain was removed from the protein backbone of rHuEPO, the in-vivo-specific activity decreased approximately two-to fourfold. Removal of two chains resulted in about a 50-fold decrease. Overall, there was a general, positive correlation between number of carbohydrate chains and in-vivo-specific activity [START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF] (Fig. 3). Whereas the position of the attached sugar chain also affected the in-vivo-specific activity, the number of chains played the more important role.

The effect of number of carbohydrate chains on EPO receptor binding activity was also examined. Unglycosylated rHuEPO, prepared by expression in Escherichia coli, had approximately sevenfold higher EPO receptor binding activity than did glycosylated rHuEPO. In contrast, as the number of N-linked carbohydrates increased, the receptor-binding activity decreased in a loglinear relationship [START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF]. The glycosylation analog with one additional N-linked carbohydrate (four in total) had a threefold reduced binding activity. Darbepoetin alfa, having two more N-linked carbohydrates than rHuEPO, had a binding activity approximately fivefold lower. N53, an analog with three additional carbohydrates compared with rHuEPO, had a 20-fold decrease. Thus, the positive relationship between carbohydrate number and in vivo activity could not be explained by increases in EPO receptor-binding activity.

Successful development of darbepoetin alfa

The novel erythropoiesis-stimulating protein darbepoetin alfa (Aranesp®) contains two additional N-linked carbohydrate chains at positions 30 and 88 as a result of five aminoacid substitutions (Ala30/Asn, His32/Thr, Pro87/Val, Trp88/Asn, Pro90/Thr) in the protein backbone [START_REF] Elliott | Enhancement of therapeutic protein in vivo activities glycoengineering[END_REF] (Fig. 4 and Table 1). The new sites were introduced at positions that did not directly interfere with the Epo:EpoR interaction or disrupt the structure or stability of the molecule. Because of the two additional N-linked carbohydrate chains, the molecular weight increased from 30 to 37 kDa and the carbohydrate part of the new molecule increased from 40% to 51%. Importantly, the maximum number of sialic-acid residues increased from 14 to 22, resulting in an increase in serum half-life [START_REF] Agoram | Investigation of the Effects of Altered Receptor Binding Activity on the Clearance of Erythropoiesis-Stimulating Proteins: Nonerythropoietin Receptor-Mediated Pathways May Play a Major Role[END_REF]. Molecules with carbohydrate contents greater than darbepoetin alfa (N53 and AMG114) and polyethylene glycol-linked darbepoetin alfa (peg-Aranesp) have also been examined, and these have a further increase in serum half-life. However, the pharmacokinetic and pharmacodynamic properties of darbepoetin alfa are appropriate for current clinical practice, indicated for administration up to once per month in certain countries, and it maintained stable Hb levels in anemic patients. In the research and development of a new ESA suitable for clinical use, there are many factors to be considered, including a reasonable balance between serum half-life and affinity to the EPO receptor. Another concern is that a serum half-life that is too long may result in loss of Hb control due to the extended time the agent can stimulate erythropoiesis. Therefore, there may be an optimal range of association of these parameters where the balance between receptor affinity, half-life, dose, and dosing interval is a beneficial one. In comparison with rHuEPO, darbepoetin alfa had a threefold serum half-life in animals [START_REF] Egrie | Darbepoetin alfa has a longer circulating half-life and greater in vivo potency than recombinant human erythropoietin[END_REF] and humans [START_REF] Macdougall | Pharmacokinetics of novel erythropoiesis stimulating protein compared with epoetin alfa in dialysis patients[END_REF][START_REF] Glaspy | Effects of chemotherapy on endogenous erythropoietin levels and the pharmacokinetics and erythropoietic response of darbepoetin alfa: a randomised clinical trial of synchronous versus asynchronous dosing of darbepoetin alfa[END_REF][START_REF] Allon | Pharmacokinetics and pharmacodynamics of darbepoetin alfa and epoetin in patients undergoing dialysis[END_REF]. In patients on peritoneal dialysis, the terminal half-life of darbepoetin alfa after intravenous administration in patients was approximately 25 h, and following subcutaneous administration, the half-life was approximately 49 h [50, 51] (Fig. 5.) However, in peritoneal dialysis and in predialysis patients after a single subcutaneous administration, the mean terminal half-life of darbepoetin alfa was between 65 and 105 h [START_REF] Allon | Pharmacokinetics and pharmacodynamics of darbepoetin alfa and epoetin in patients undergoing dialysis[END_REF]. The apparent terminal half-life of darbepoetin alfa was twofold longer with the subcutaneous compared with intravenous route of administration. The dose requirement in order to maintain similar hemoglobin serum levels in patients with anemia was similar with the two routes of administration, indicating there was no loss of efficiency [START_REF] Mann | Darbepoetin alfa once every 2 weeks for treatment of anemia in dialysis patients: a combined analysis of eight multicenter trials[END_REF]. The similar dose requirement is explained by the longer half-life associated with subcutaneous route resulting in longer exposure of the drug, which compensates for the reduced subcutaneous bioavailability (∼37%).

Darbepoetin alfa has a fivefold decreased receptorbinding-specific activity compared with rHuEPO [START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF][START_REF] Egrie | Darbepoetin alfa has a longer circulating half-life and greater in vivo potency than recombinant human erythropoietin[END_REF]. Therefore, the minimal effective concentration (MEC), or in other words, erythropoiesis threshold, is higher with darbepoetin alfa compared with rHuEPO. This suggests that higher serum concentrations of darbepoetin alfa may be required to get similar fractions of ESA-bound receptors, which theoretically could result in reduced in-vivo-specific activity or efficacy. However, the additional carbohydrate on darbepoetin did not blunt the biological response [START_REF] Sinclair | Glycoengineering: the effect of glycosylation on the properties of therapeutic proteins[END_REF], and the same signal transduction pathways were stimulated with similar kinetics and magnitude [START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF][START_REF] Sinclair | Glycoengineering: the effect of glycosylation on the properties of therapeutic proteins[END_REF]. When in vitro and in vivo activities were compared, the shapes of the dose-response curve, maximal stimulation, and hematological response were all similar, suggesting that the different carbohydrate content can affect the specific activity but did not affect function per se.

Darbepoetin alfa actually has increased in-vivo-specific activity compared with rHuEPO despite its reduced receptor-binding-specific activity. In a multicycle carboplatin chemotherapy/radiotherapy model in mice [START_REF] Hartley | Kinetics of haematopoietic recovery after dose-intensive chemo/radiotherapy in mice: Optimized erythroid support with darbepoetin alpha[END_REF], a sixfold higher dose of rHuEPO was required to match the effect of the lower dose of darbepoetin alfa. In normal mice, in order to maintain or elicit a similar erythropoietic response, three times more rHuEPO was needed than darbepoetin alfa to provide the same response at three times per week administration in mice [START_REF] Egrie | Darbepoetin alfa has a longer circulating half-life and greater in vivo potency than recombinant human erythropoietin[END_REF][START_REF] Sasu | Comparison of epoetin alfa and darbepoetin alfa biological activity under different administration schedules in normal mice[END_REF] (Fig. 6). When the dosing interval was extended to weekly administration, the difference increased to 13-fold. With a single injection, the dose of rHuEPO needed to be 30-40 times higher to match the effect of the lower dose of darbepoetin alfa. This and the relative in-vivo-specific activity of darbepoetin alfa compared with rHuEPO increased with increasing dosing interval. Increased specific activity of darbepoetin alfa compared with rHuEPO was also reported in human clinical studies [START_REF] Tolman | Structured conversion from thrice weekly to weekly erythropoietic regimens using a computerized decision-support system: a randomized clinical study[END_REF]. In humans administered darbepoetin alfa with a Q2W (every other week) dosing regimen, the same total dosage could successfully maintain Hb levels in renal anemic dialysis patients in comparison with QW (weekly) administration of the drug [START_REF] Carrera | The efficacy of intravenous darbepoetin alfa administered once every 2 weeks in chronic kidney disease patients on hemodialysis[END_REF]. Similarly, in the predialysis population, QM (monthly) administration of the drug maintained Hb concentration at the same total dose in comparison with Q2W administration [START_REF] Ling | Darbepoetin alfa administered once monthly maintains haemoglobin concentration in patients with chronic kidney disease[END_REF]. However it is not clear whether a relative increase in dose is required for monthly administration in dialysis or other patients.

Fig. 5 Darbepoetin alfa serum concentration in stable peritoneal dialysis patients remains above the minimal effective concentration (MEC) for erythropoiesis longer than an equivalent dose of recombinant human erythropoietin (rHuEPO) (from [START_REF] Macdoughall | Optimizing the use of erythropoietic agents-pharmacokinetic and pharmacodynamic considerations[END_REF], with permission) Fig. 6 In vivo activity of darbepoetin alfa increases compared with recombinant human erythropoietin (rHuEPO) as dose interval increases in mice [START_REF] Egrie | Darbepoetin alfa has a longer circulating half-life and greater in vivo potency than recombinant human erythropoietin[END_REF][START_REF] Sasu | Comparison of epoetin alfa and darbepoetin alfa biological activity under different administration schedules in normal mice[END_REF] The apparent paradox, that rHuEPO glycosylation analogs with reduced receptor-binding-specific activity had increased in vivo specific activity, is explained by the counteracting effects of sialic-acid-containing carbohydrate on clearance. Slower clearance in vivo results in a slower decline in serum concentration over time when slow and faster clearing molecules are compared, and the relative concentration differences will increase with time. In addition, the ESA doses typically used clinically are sufficiently high to ensure sufficient numbers of EPO receptors are bound for effective erythropoiesis. As a result, the prolonged drug exposure more than compensates for the reduced receptor-binding-specific activity [START_REF] Elliott | Control of rHuEPO biological activity: The role of carbohydrate[END_REF] (Fig. 7a) and can result in increased in-vivo-specific activity.

In practice, half life and binding affinity to the EPOR can move independently from each other. Therefore, a longer half-life may not necessarily result in increased specific bioactivity. For example, a drug with sixfold longer half-life may not show increased specific activity if the affinity to the receptor was substantially lower, e.g., 50-fold (Fig. 7b). This would be especially true if the starting concentration was not high enough to ensure that sufficient EPO receptors were bound following ESA administration. An additional issue with agents that have substantially prolonged serum half lives is that an overshoot in Hb levels may occur because of the prolonged time that erythropoi-esis is stimulated. To reduce this possibility, lower starting doses may be used, and a longer period of time may elapse before a dose adjustment might be made. These issues limit the ability to implement a frequent dose titration if the patient or caregiver required it.

Binding of EPO to EPOR can result in either dissociation from its receptor, or the complex (EPO-EPOR) can be internalized into the cell where degradation occurs. Possibly, affinity to the receptor affected the likelihood that ESA would be bound and therefore the rate at which degradation could occur. Therefore, some have suggested that there is a causal relationship between slower clearance and reduced receptor affinity [START_REF] Egrie | Development and characterization of novel erythropoiesis stimulating protein (NESP)[END_REF].

To determine whether differences in affinity to the EPO receptor translated into differences in clearance, intracellular trafficking of darbepoetin alfa and rHuEPO were assessed in vitro in an EPO-dependent cell line [START_REF] Gross | Cellular trafficking and degradation of erythropoietin and novel erythropoiesis stimulating protein (NESP)[END_REF]. With rHuEPO, approximately 57% of bound material was internalized into the cell. Whereas 60% of EPO was recycled intact to the cell surface, 40% of the internalized material was degraded. This observation suggests that EPOR-mediated binding endocytosis and degradation could clear this agent. Whereas the reduced EPO receptor affinity of darbepoetin alfa did affect the likelihood of binding, the intracellular trafficking of rHuEPO and darbepoetin alfa were similar.

To determine whether EPOR-mediated degradation explained the reduced clearance of darbepoetin alfa in vivo, experiments with rHuEPO analogs with different receptor binding and clearance properties were performed [START_REF] Agoram | Investigation of the Effects of Altered Receptor Binding Activity on the Clearance of Erythropoiesis-Stimulating Proteins: Nonerythropoietin Receptor-Mediated Pathways May Play a Major Role[END_REF]. Pharmacokinetic characteristics of an EPO analog (NM385), which had no detectable EPOR binding activity, showed only a modest difference in clearance compared with rHuEPO. In contrast, darbepoetin alfa and its polyethylene glycol-linked form had longer half-lives and reduced clearance compared with NM385. Assuming that NM385 with a complete block in Epo-receptor-mediated clearance represented the maximum effect of Epo-receptormediated clearance, and observing that darbepoetin alfa had a longer serum half-life than NM385, then the longer halflives of darbepoetin alfa and its polyethylene-glycol-linked form must be due to a reduction in clearance of pathways independent of the EPO receptor.

Other ESAs

As with darbepoetin alfa, other ESAs, such as pegylated forms of rHuEPO, biosimilars, or EPO mimetic peptides (Hematide), have the same mechanism of action as rHuEpo: binding and activation of EPOR [START_REF] Eliott | Erythropoiesis: a common mechanism of action[END_REF]. However, they can be differentiated from each other according to differences in manufacturing methods, affinity to the EPO receptor, and 7 a Model for darbepoetin alfa, which has decreased receptor affinity and longer half-life than recombinant human erythropoietin (rHuEPO). Longer serum half-life of darbepoetin alfa more than compensates for reduced affinity. b Dramatically reduced receptor affinity limits gain in biological activity due to longer half-life serum half-life. As a result, in clinical practice, all these differences should be considered simultaneously. Mircera ® (methoxy polyethylene glycol-epoetin beta) is epoetin beta with a covalent attachment to the peptide backbone of a linear methoxypolyethylene glycol (PEG), resulting in approximately a doubling in size compared with epoetin alfa (30.4 vs 60 kDa) [START_REF] Jarsch | Comparative erythropoietin receptor binding kinetics of C.E.R. A. and epoetin-beta determined by surface plasmon resonance and competition binding assay[END_REF]. PEG-epoetin beta has a prolonged elimination half-life in patients with CKD, approximately 134 h [START_REF] Macdougall | Pharmacokinetics and pharmacodynamics of intravenous and subcutaneous continuous erythropoietin receptor activator (C.E.R.A.) in patients with chronic kidney disease[END_REF]. Mircera ® is approved to treat anemia associated with CKD in Europe. Hematide is a synthetic ESA comprised of nonnaturally occurring amino acids in a dipeptide that binds to the EPO receptor, thereby activating it [START_REF] Fan | Preclinical evaluation of Hematide, a novel erythropoiesis stimulating agent, for the treatment of anemia[END_REF][START_REF] Stead | Evaluation of the safety and pharmacodynamics of Hematide, a novel erythropoietic agent, in a phase 1, double-blind, placebo-controlled, dose-escalation study in healthy volunteers[END_REF]. The peptide was pegylated to increase serum half-life and is currently in clinical development.

Conclusions

In the past 20 years, our knowledge concerning erythropoietin and erythropoiesis has increased significantly. The first milestone was to introduce rHuEPO into clinical practice. This dramatically changed treatment options, increased energy levels of patients and reducing the incidence of transfusions. Whereas the biological function of rHuEPO is typically determined by the protein component, carbohydrate can play a role in molecular stability, solubility, in vivo activity, serum half-life, and immunogenicity. Darbepoetin alfa, an rHuEPO analog with two additional N-linked carbohydrate chains, was discovered and developed. Darbepoetin alfa has been used to successfully treat anemia in many patient populations, including those with chemotherapyinduced anemia and anemia associated with CKD. Darbepoetin alfa is cleared more slowly from the body and has a longer-lasting effect, resulting in a higher invivo-specific activity compared with rHuEPO. Darbepoetin alfa is indicated for an increased interval between administrations of the drug.

Fig. 3 Fig. 4

 34 Fig. 3 In vivo activity of erythropoietin (EPO) glycosylation analogs increases with increasing number of N-linked carbohydrate chains ([from 39], with permission)

  Fig.7a Model for darbepoetin alfa, which has decreased receptor affinity and longer half-life than recombinant human erythropoietin (rHuEPO). Longer serum half-life of darbepoetin alfa more than compensates for reduced affinity. b Dramatically reduced receptor affinity limits gain in biological activity due to longer half-life

Table 1

 1 Characteristics of different ESAs[START_REF] Elliott | Structural requirements for additional N-linked carbohydrate on recombinant human erythropoietin[END_REF][START_REF] Macdougall | Pharmacokinetics of novel erythropoiesis stimulating protein compared with epoetin alfa in dialysis patients[END_REF][START_REF] Jarsch | Comparative erythropoietin receptor binding kinetics of C.E.R. A. and epoetin-beta determined by surface plasmon resonance and competition binding assay[END_REF][START_REF] Macdougall | Pharmacokinetics and pharmacodynamics of intravenous and subcutaneous continuous erythropoietin receptor activator (C.E.R.A.) in patients with chronic kidney disease[END_REF][START_REF] Fan | Preclinical evaluation of Hematide, a novel erythropoiesis stimulating agent, for the treatment of anemia[END_REF][START_REF] Stead | Evaluation of the safety and pharmacodynamics of Hematide, a novel erythropoietic agent, in a phase 1, double-blind, placebo-controlled, dose-escalation study in healthy volunteers[END_REF] ESA (marketed name)

	Serum half-life (relative	to epoetin alfa)	same	Similar	Similar	Not Available		Similar	Similar	Extended		Extended		Extended
	Physical characteristics		165 amino acids (∼30 kDa)	Similar	Similar	Similar		Similar	Similar	165 amino acids, 5 amino acid differences, 2 additional	N-linked carbohydrate chains (∼38 kDa)	165 amino acids, addition of a 30 kDa polyethylene	glycol moiety ∼ 60 kDa	Synthetic, dimeric peptidic ESA with an amino acid	sequence unrelated to rHuEpo, covalently linked to	polyethylene glycol
	Receptor affinity	(relative to epoetin alfa)	Same	Similar	Similar	Slightly increased		Similar	Similar	Reduced (∼5-fold)		Reduced (50 to	100 fold)	Reduced (∼5-fold)
	Cell type used for	manufacturing	CHO a	CHO a	HT-1080 b	Baby Hamster	Kidney	CHO a	CHO a	CHO a		CHO a		Synthetic
	Greek name		Epogen®/ Procrit®/ Eprex®/Erypro® Epoetin alfa	Epoetin beta Recormon®/Neorecormon®	Epoetin delta Dynepo®	Epoetin omega Repotim™		Epoetin zeta Silapro®/ Retacrit®	Epoetin alfa Abseamed®/Binocrit®/Hexal®	Darbepoetin alfa Aranesp®		Methoxy polyethylene Mircera®	glycol-epoetin beta	Not available HematideTM	a CHO Chinese hamster ovary

b Human fibrosarcoma cells

Eur J Clin Pharmacol (2010) 66:331-340

Acknowledgements The manuscript was sponsored by Amgen (Hungary). Vladimir Tesar participated in the advisory board for Amgen and Novartis; received a research grant from Amgen and lecture fees from Amgen, Astra Zeneca, Fresenius Kabi, Novartis, Roche and Teva. János Szegedi received consulting fees from Amgen and Janssen Cilag and participated in the advisory board for Amgen. Zoltán Kiss, Steven Elliott, Kinga Jedynasty are employees of Amgen.