A biosimilar is defined by the European Medicines Agency as a biological medicine that is similar to another biological medicine that has already been authorized for use. A science-based regulatory framework to ensure high-quality biosimilars has been established in Europe since 2005 and is monitored and updated on an ongoing basis. The guiding principle of a biosimilar development program is to establish similarity between the biosimilar and the reference medicine by the best possible means, ensuring that the previously proven safety and efficacy of the reference medicinal product also applies to the biosimilar. Development of a biosimilar is underpinned by state-of-the-art analytical techniques to characterize both reference medicines and biosimilars. The extent and nature of the nonclinical in vivo studies and clinical studies to be performed depend on the level of evidence obtained in the previous step(s), including the robustness of the physicochemical, biological, and nonclinical in vitro data. Extrapolation is an important element of the biosimilarity concept. When biosimilar comparability has been demonstrated in one indication, extrapolation of the data package to other indications of the reference medicine could be acceptable, but needs to be scientifically justified and considered in light of the demonstrated level of sameness by all analytical, nonclinical, and clinical data. The credibility of the scientific basis behind the biosimilar concept, and quality of regulatory decision-making, is demonstrated by the successful approval and clinical use of 20 biosimilar medicines since 2006 when Omnitrope® was the first biosimilar to be approved. The regulatory environment for biosimilars continues to evolve, both in recognition of advances in technology/analytical methods and the availability of new targets for biosimilar development.

The efficacy and safety profile of Omnitrope(®) in the PATRO Children study so far are as expected. The ongoing study will extend the safety database for Omnitrope(®), and rhGH products more generally, in paediatric indications. Of particular interest, PATRO Children will add important information on the diabetogenic potential of rhGH in children born SGA, the risk of malignancies in children receiving rhGH, and AEs with a possible causal relationship to rhGH treatment in children with PWS.

IntroductionRecombinant human growth hormone (rhGH) is effective and safe when used to treat growth hormone deficiency (GHD) in children. However, it has been suggested that switching between different types of rhGH can have a detrimental effect on patients.MethodsThe current analysis assessed the efficacy and safety of rhGH in children who received continuous Omnitrope® (Sandoz GmbH, Kundl, Austria) therapy either with lyophilized powder for solution or ready-to-use solution, with children who received 9 months of treatment with Genotropin® (Pfizer Limited, Sandwich, UK) followed by Omnitrope solution thereafter. Changes to height, height SD score (SDS), height velocity SDS, insulin-like growth factor (IGF-1) levels, and IGF binding protein (IGFBP-3) levels were assessed using data from three trials.ResultsBaseline demographics of the three study groups were similar. Over an 18-month period there were no observable differences between the three groups with respect to height, height SDS, height velocity SDS, IGF-1 levels, and IGFBP-3 levels. This result was corroborated by the model data, whereby most data points for Omnitrope-treated children fell within the defined limits of the prediction model based on Genotropin data. Few adverse drug reactions (ADRs) occurred.ConclusionsSwitching from Genotropin to Omnitrope solution has no impact on efficacy or safety in children with GHD, and the various rhGH preparations are well tolerated.

Abstract:Objective: To describe the rationale and design of PATRO Adults, a postmarketing surveillance study of the long-term efficacy and safety of somatropin (Omnitrope ® ) for the treatment of adult patients with growth hormone deficiency (GHD). Methods: PATRO Adults is an observational, multicentre, open, longitudinal, noninterventional study being conducted in hospitals and specialized endocrinology clinics across several European countries. The primary objective is to assess the safety and efficacy of Omnitrope ® in adults treated in routine clinical practice. Eligible patients are male or female adults who are receiving treatment with Omnitrope ® and who have provided informed consent. Patients who have been treated with another human growth hormone (hGH) product before starting Omnitrope ® therapy will also be eligible for inclusion. Efficacy assessments will be based on the analysis of the following: insulin-like growth factor-1 levels within age-and gender-adjusted normal ranges; anthropometric measures (weight, waist circumference, total fat mass, lean body mass, total body water); bone mineral density; lipids; effects on cardiovascular risk factors such as glucose metabolism, blood pressure and inflammatory markers (e.g. C-reactive protein); and quality of life. All adverse events will be monitored and recorded. Particular emphasis will be placed on long-term safety, the recording of malignancies, the occurrence and clinical impact of antirecombinant hGH antibodies, the incidence, severity and duration of hyperglycaemia, and the development of diabetes during treatment with Omnitrope ® .

Close adherence to the recommended treatment regimen is important for the success of recombinant human growth hormone therapy, although nonadherence can be common. Ease of use and safety during use/storage are among several important factors in the design of a growth hormone injection device intended for long-term use. This study was performed to validate the usability and assess the ease of use of a new pen device (SurePal™) that has been developed to support daily administration of the recombinant human growth hormone product, Omnitrope® (somatropin). The primary objectives of the study were to assess if study participants, representing intended users of the pen in clinical practice, were able to perform an injection procedure into an injection pad effectively and safely and disassemble the pen without receiving a needlestick injury. A total of 106 participants (61 adults and 45 children/adolescents) were enrolled at two study centers (one in the US, one in Germany). Results for both primary usability tasks met the predefined acceptance criteria, with >85% of participants successfully performing each task. All of the other tasks/handling steps assessed were also successfully performed by most participants, with high success rates reflected in the high proportion of participants who classified each task as “very easy” or “easy”. After a second use of the device, 87%–97% of participants rated it as “very easy” or “easy” to use. In summary, the new pen device is safe and easy to use for both adults and children, and will help to support effective, long-term daily administration of the recombinant human growth hormone product, Omnitrope®.

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This article discusses the bioequivalence of Omnitrope (Sandoz's rhGH biosimilar) and Genotropin (reference rhGH product), assessed in the first 2 clinical phase 1 studies conducted during the development of Omnitrope. Both of these phase 1 studies were randomized, double-blind, crossover studies, each involving 24 healthy volunteers who underwent pituitary somatrope cell down-regulation using octreotide. Three different formulations of recombinant human growth hormone (rhGH) were compared: Omnitrope lyophilisate, Omnitrope liquid and Genotropin (lyophilized powder for injection). Both pharmacokinetics (area under the curve [AUC], C(max), t(max) and t(1/2)) and pharmacodynamics (serum levels of insulin-like growth factor 1, insulin-like growth factor binding protein-3 and non-esterified fatty acid) were assessed after a single subcutaneous injection of 5 mg rhGH. The 3 formulations had comparable pharmacokinetics and pharmacodynamics. All the 90% confidence intervals of the ratios of the least squares means for the pharmacokinetic and pharmacodynamic parameters AUC and C(max) were within the predefined FDA and EMEA acceptance range of 80%-125% for bioequivalence. In addition, a comparative population pharmacokinetic analysis further supports that Omnitrope lyophilisate, Omnitrope liquid and Genotropin can be regarded as equivalent in terms of pharmacokinetics. Therefore, Omnitrope lyophilisate was demonstrated to be bioequivalent to both Genotropin and the Omnitrope liquid formulation.

In 2006, the European Medicines Agency (EMA) approved Omnitrope® as a biosimilar recombinant human growth hormone (rhGH), on the basis of comparable quality, safety, and efficacy to the reference medicine (Genotropin®, Pfizer). Data continue to be collected on the long-term efficacy of biosimilar rhGH from several on-going postapproval studies. Particular topics of interest include efficacy in indications granted on the basis of extrapolation, and whether efficacy of growth hormone treatment is affected when patients are changed to biosimilar rhGH from other rhGH products. Data from clinical development studies and 10 years of postapproval experience affirm the clinical efficacy and effectiveness of biosimilar rhGH across all approved indications. In addition, the decade of experience with biosimilar rhGH since it was approved in Europe confirms the scientific validity of the biosimilar pathway and the approval process. Concerns about clinical effect in extrapolated indications, and also about the impact of changing from other rhGH preparations, have been alleviated. Biosimilar rhGH is an effective treatment option for children who require therapy with rhGH.