Ten years with biosimilar rhGH in clinical practice in Sweden - experience from the prospective PATRO children and adult studies.

BACKGROUND: In 2007, Omnitrope® was the first biosimilar recombinant human growth hormone (rhGH) to be approved in Sweden for treatment in adults and children. Over 10 years' safety and effectiveness data for biosimilar rhGH can now be presented.

METHODS: PATRO Children and PATRO Adults are multicenter, longitudinal, observational, post-marketing surveillance studies. Eligible patients include children 0-18 years and adults receiving biosimilar rhGH treatment. Adverse events (AEs) are monitored for safety evaluation. Growth variables in children and metabolic data in adults are recorded for effectiveness evaluation.

RESULTS: As of January 2019, data from 136 children (48% male) were reported from Swedish centers. Mean age in rhGH treatment-naïve patients at study entry (n = 114) was 7.5 years, with mean 3.6 years treatment duration. No severe AEs of diabetes, impaired glucose tolerance, or malignancy were reported. The most frequently reported AE was nasopharyngitis (n = 16 patients). No clinically relevant anti-hGH or neutralizing antibodies were observed. The mean change from baseline in height standard deviation score (SDS) in naïve prepubertal GH deficiency patients was + 0.79 at 1 year, + 1.27 at 2 years, and + 1.55 at 3 years. Data from 293 adults (44% rhGH-naïve, 51% male) were included. Fatigue was the most frequently reported AE (n = 26 patients). The incidence of new neoplasms or existing neoplasm progression was 23.8 patients per 1000 patient-years. Type 2 diabetes mellitus was reported in four patients. At baseline in rhGH-naïve adults, mean (SD) body mass index (BMI) was 29.1 (5.6) kg/m2 and mean (SD) insulin-like growth factor (IGF)-I SDS was - 3.0 (1.4). Mean daily dose increased from 0.1 mg at baseline to 0.3 mg after 4 years. IGF-I SDS normalized during the first year of treatment. Mean BMI and glucose were unchanged over 4 years, while low-/high-density lipoprotein cholesterol ratio decreased.

CONCLUSIONS: For the first time, Swedish data from the PATRO Children and Adults studies are presented. The 10-year data suggest that biosimilar rhGH is well tolerated across pediatric and adult indications. Safety and effectiveness were similar to previous reports for other rhGH preparations. These results need to be confirmed in larger cohorts, highlighting the importance of long-term post-marketing studies.