[What doctors need to know about biosimilar medicinal products?]. / Sto bi lijecnici trebali znati o bioloski slicnim lijekovima?

Biological drug is a drug containing one or more active substances produced or secreted from a biological source. Some of them may be previously present in the human body, and examples include proteins such as insulin, growth hormone or erythropoetin. Biosimilar drug is a medical product that is a copy of the original approved drug whose patent has expired. Strict rules apply to similar biological medicines: 1) it is unable to support extrapolation of data on safety and efficacy between individual indications, except in the case of appropriate, science-based evidence; 2) biosimilar drugs must meet the requirements associated with testing the immunogenicity and safety monitoring afterthe introduction of the drug in clinical practice, including the risk management program; 3) each biosimilar drug has to be labeled under its own name in order to allow clear traceability of all medications; and 4) the principle of automatic substitution cannot apply to biosimilar drugs because they are not interchangeable.

Consensus statement on the standardization and evaluation of growth hormone and insulin-like growth factor assays.

Growth hormone (GH) and insulin-like growth factor I (IGF-I) measurements are widely used in the diagnosis of disorders of GH secretion, evaluation of children with short stature from multiple causes, management of disorders that lead to nutritional insufficiency or catabolism, and monitoring both GH and IGF-I replacement therapy. Therefore, there is an ongoing need for accurate and precise measurements of these 2 peptide hormones. Representatives of the Growth Hormone Research Society, the IGF Society, and the IFCC convened an international workshop to review assay standardization, requirements for improving assay comparability, variables that affect assay interpretation, technical factors affecting assay performance, assay validation criteria, and the development and use of normative data. Special attention was given to preanalytical conditions, the use of international commutable reference standards, antibody specificity, matrix requirements, QC analysis, and interference by binding proteins. Recommendations for each of these variables were made for measurements of each peptide. Additionally, specific criteria for IGF-I were recommended for age ranges of normative data, consideration of Tanner staging, and consideration of the effect of body mass index. The consensus statement concludes that major improvements are necessary in the areas of assay performance and comparability. This group recommends that a commutable standard for each assay be implemented for worldwide use and that its recommendations be applied to accomplish the task of providing reliable and clinically useful results.

Bovine growth hormone: human food safety evaluation.

Scientists in the Food and Drug Administration (FDA), after reviewing the scientific literature and evaluating studies conducted by pharmaceutical companies, have concluded that the use of recombinant bovine growth hormone (rbGH) in dairy cattle presents no increased health risk to consumers. Bovine GH is not biologically active in humans, and oral toxicity studies have demonstrated that rbGH is not orally active in rats, a species responsive to parenterally administered bGH. Recombinant bGH treatment produces an increase in the concentration of insulin-like growth factor-I (IGF-I) in cow's milk. However, oral toxicity studies have shown that bovine IGF-I lacks oral activity in rats. Additionally, the concentration of IGF-I in milk of rbGH-treated cows is within the normal physiological range found in human breast milk, and IGF-I is denatured under conditions used to process cow's milk for infant formula. On the basis of estimates of the amount of protein absorbed intact in humans and the concentration of IGF-I in cow's milk during rbGH treatment, biologically significant levels of intact IGF-I would not be absorbed.

Tracing recombinant bovine somatotropin ab(use) through transcriptomics: the potential of bovine somatic cells in a multi-dose longitudinal study.

In the European Union, the use of recombinant bovine somatotropin (rbST) in dairy cattle is forbidden. Monitoring rbST (ab)use by its direct detection in animal matrices still remains a challenging task. New monitoring methods based on indirect detection of the substance are necessary. A new transcriptomic system based on the use of high-throughput real-time PCR in combination with somatic cells was developed to control rbST administration in dairy animals. A total of nine cows, separated into control and rbST-treated groups, were included in the study. A subcutaneous injection containing 500 mg of rbST was administered to the treated group every 14 days, up to a total of 12 doses. Milk somatic cells (MSCs) were sampled from each animal at different time points throughout 8 months of study. It was possible to obtain the transcriptomic profile of 18 genes in MSCs of rbST-treated and control groups, and using univariate and multivariate statistical analysis control and treated animals were discriminated. The transcription of CCND1, IGF-1R, TNF and IL-1ß genes resulted strongly influenced by rbST treatment. The combination of MSCs, transcriptomic tools and statistical analysis has allowed the selection of four genes as potential biomarkers that could be used in a transcriptomic panel for monitoring rbST administration in cows.

Similar biological medicinal products containing recombinant human growth hormone: European regulation.

The concept of similar biological medicinal products ('biosimilar' medicinal products) allows pharmaceutical companies to develop products based on an abridged dossier once the marketing protection of the 'reference' biological medicinal product has expired. A biosimilar medicinal product can be granted a marketing authorization provided that its similarity to a reference product is established in terms of quality, safety and efficacy (step-wise comparability exercise). A decision to launch a biosimilar medicinal product on the market is taken if it has a similar efficacy and comparable or better (less) immunogenicity than the chosen reference biological medicinal product. However, this decision is based on limited data and the comparability program may detect substantial differences in immunogenicity profiles but is likely incapable of detecting rare events. This is why clinical experience, through clinical trials and extensive pharmacovigilance programs, remains the most reliable way to assess the immunogenicity and tolerance profile of recombinant therapeutic proteins. Substitution of one biological medicinal product by a biosimilar medicinal product is not currently recommended before long-term clinical efficacy and safety have been acquired in all relevant populations. Here we review recent regulatory guidelines provided by EMEA and comment on the marketing authorizations and risk management plans of two recently approved biosimilar somatropins.

Clinical review 21: The efficacy and safety of growth hormone for animal agriculture.

Public understanding, perception, and acceptance are important for the benefits of biotechnology to be realized. Based upon sound scientific evidence, GH does not appear to pose any risk to the consumer. More than 1000 papers have been published about bGH and pGH, and the principal lines of evidence supporting the position that they are safe are reviewed herein. Recently, an independent committee appointed by The National Institutes of Health examined the available data and concluded that "The evidence clearly indicates that the overall composition and nutritional quality of milk and meat from bGH-treated cows is equal to that from untreated cows". Similarly, the FDA has concluded that the use of bGH presents no increased health risk to consumers. In addition, there is compelling evidence to indicate that GH poses no increased health risk to the target animal. Thus, GH treatment of farm animals is not only an effective technology for increasing productive efficiency but one that poses no increased health risk for either the consumer or the target animal.

The International Standard for Human Growth Hormone for Bioassay: calibration and characterization by international collaborative study.

Two preparations of human growth hormone (hGH) were prepared as candidates for the International Standard for Human Growth Hormone for Bioassay and were studied by 22 laboratories in 10 countries in an international collaborative study. The 2 candidate preparations, freeze-dried in ampoules coded 80/505 and 80/521, were assayed against the International Standard for Growth Hormone, bovine, for Bioassay (ISbGH), by in vivo assays; against the International Reference Preparation of Growth Hormone, human, for Immunoassay (IRP hGH), by receptor-, immunoassays and other in vitro methods; and against each other by various methods. Both preparations contained the 2 recognized main growth hormone components (22 kDa and 20 kDa forms) and other components, but that in ampoules coded 80/505 had less deamidated hGH and contaminant hormones and pyrogen than that in ampoules coded 80/521. The estimates by in vivo bioassays, using immature hypophysectomized rats, of the potency of 80/505 in terms of the IS bGH were heterogeneous (1-6 IU/ampoule), probably because of the dissimilarity of the preparations of bovine and human GH. Estimates with receptor- and immunoassays of 80/505 against the IRP hGH were also heterogeneous (3-9 IU/ampoule). Nevertheless, the majority of estimates from all assays tended to be between 3 and 6 IU/ampoule. Although 80/521 and 80/505 differed in relatively minor respects, assays of one directly against the other gave relative potency estimates with in vivo assays which were significantly different from estimates with in vitro methods. With the agreement of the participants in the study, the WHO Expert Committee on Biological Standardization established the preparation in ampoules coded 80/505 as the First International Standard for Human Growth Hormone for Bioassay, with the defined potency of 4.4 IU/ampoule. This corresponds to an approximate 2.5 IU/mg of hGH extract and maintains reasonable continuity of the unit.

Review of Turkish patients with growth hormone insensitivity (Laron type).

Clinical spectrum and endocrine details of thirteen Turkish children (age 0.3-14.2 years; eight females and five males; ten prepubertal, three pubertal) with growth hormone insensitivity are presented. All patients display phenotypical features of severe growth hormone deficiency. The diagnosis based on height standard deviation score (SDS), basal growth hormone (GH), basal insulin-like growth factor I (IGF-I, IGF-I response in an IGF generation test and growth hormone binding protein (GHBP) measurements. The median height SDS was -7.4 (range -3.2 to -10), weight for height index was 100 (range 81-152) and bone age/height age ratio was 2 (range 1.6-3.3). Endocrine investigations showed a median basal GH concentration of 61.4 mU/l (range 23.5-120 mU/l). Basal IGF-I level was below 10 ng/ml in all patients except one. None of the patients showed a significant IGF-I response to injections of GH (0.1 U/kg body weight for 4 days). The median IGFBP-3 level was 0.23 mg/l (range 0.1-0.56 mg/l). The GHBP level was undetectable in all of 10 patients. The high number of patients in our center may be due to the high rate of consanguinity among the Turkish population and the referral facility of our center in the area. These patients may benefit from the new therapy with recombinant human IGF-I.

Human growth hormone: the dilemma of expanded use in children.

In the specialized area of pediatric endocrinology, the use of human growth hormone (hGH) both for children who have a growth hormone abnormality and for the treatment of non-hGH-deficient children who are short is a current clinical reality that raises important ethical questions. Generally speaking, the use of hGH for those children who are clearly lacking it is an efficacious intervention based upon established clinical criteria. The use of hGH for children who are short, but have no growth hormone abnormality is ethically and clinically more controversial. The moral conundrum of how to gain knowledge about new medical treatments that may be beneficial to children while, at the same time, ethically enrolling them in clinical trials with placebo arms in order to gain such knowledge will continue to be a contentious issue in the conduct of research and in the delivery of health care. In addition, there are questions about what ought to be studied and whether a physical characteristic such as short stature ought to be viewed as a circumstance of less than optimal health.

Comparative effectiveness of somatotropin and anabolic steroids in feedlot steers.

Crossbred steers (n = 252, BW = 379 +/- 28 kg) were allotted to 42 pens in a 2 x 3 factorial arrangement of treatments: control or steroid implant (STR; estradiol benzoate+progesterone [three lighter blocks reimplanted on d 84] and trenbolone acetate [reimplanted on d 63]), and either 0, 80, or 160 mg/wk of recombinant bovine somatotropin (bST). Steers were adapted to the finishing diet (12% roughage equivalent, 13% CP) before the start of the experiment and fed for 84 or 119 d. Blood samples were taken on d 0, 14, 28, 56, and 84 for plasma urea N (PUN), serum somatotropin (ST), plasma insulin-like growth factor I (IGF-I), and plasma amino acid assay. Few interactions were noted (P > .1). Gain was increased by both treatments: 1.30 vs 1.66 kg/d for control vs. STR (P < .001) and 1.44, 1.49, and 1.51 kg/d (linear, P = .07) for 0, 80, and 160 mg of bST/wk, respectively. Gain efficiency was also improved: 169 vs 205 g/kg (P < .001) and 177, 189, and 195 g/kg (linear, P < .001), respectively. Average PUN was decreased (P < .001) 29% by STR and decreased 17 and 29% by 80 and 160 mg of bST/wk, respectively (linear, P < .001). Somatotropin decreased mean serum ST compared with controls; STR increased ST 36% compared with controls. Average plasma IGF-I was increased (P < .001) 12% by STR and 13 and 19% (linear, P < .001) by 80 and 160 mg of bST/wk, respectively. Both STR and bST influenced (P < .05) plasma amino acid profiles. Indicators of carcass fatness were decreased linearly (P < .05) by bST; STR implant tended to decrease carcass fatness and increase longissimus muscle area, which was related to carcass weight. The anabolic effects of STR and bST were found to be additive and possibly independent in feedlot steers.

International harmonization issues.

With the globalization of trade in many product sectors occurring at a rapid pace, interest in international harmonization issues relating to veterinary products continues to grow. Because of the potential impact on trade, there has been a focus for several years on harmonization of maximum residue limits (MRLs) or tolerances on a global basis. There has also been interest, especially on the part of pharmaceutical companies, to facilitate the approval of a veterinary product in multiple countries. This article discusses two major international initiatives that have been formed to address these harmonization areas of concern for veterinary products.

International collaborative study for the calibration of the Ph. Eur. somatropin chemical reference substance batches 3 and 4 (BSP108).

An international collaborative study was carried out for the establishment of replacement batches for the European Pharmacopoeia (Ph. Eur.) Somatropin Chemical Reference Substance (CRS) batch 2. The study was organised within the framework of the Biological Standardisation Programme (BSP) of the Council of Europe and the European Commission. Seventeen laboratories from Europe, North America, South America and Australia took part in the collaborative study. The study aimed at calibrating the somatropin content of 2 candidate preparations and demonstrating their suitability to serve as a reference substance in the tests for identification, for related proteins, for dimers and related substances of higher molecular mass (HMM), for charged variants distribution and for the assay of somatropin, as prescribed by the current Ph. Eur. monographs 0950 Somatropin bulk solution, 0951 Somatropin and 0952 Somatropin for injection. Based on the results summarised herein the Ph. Eur. Commission adopted in January 2012 candidate preparation b (cCRS-b, Sample D) as somatropin CRS batch 3 with an assigned content of 3.86 mg of somatropin monomer per vial, and candidate preparation a (cCRS-a, Sample C) as somatropin CRS batch 4 with an assigned content of 2.59 mg of somatropin monomer per vial.