Malignancy risk in adults with growth hormone deficiency undergoing long-term treatment with biosimilar somatropin (Omnitrope®): data from the PATRO Adults study

Background: To assess the safety (particularly the occurrence of malignancies) of growth hormone (GH) replacement (Omnitrope®) in adults with GH deficiency, using data from the ongoing PATRO Adults post-marketing surveillance study. Methods: PATRO Adults is being conducted in hospitals and specialized endocrinology clinics across Europe. All enrolled patients who receive ⩾1 dose of Omnitrope® are included in the safety population. Malignancies are listed as adverse events under the MedDRA System Organ Class ‘neoplasms, benign, malignant and unspecified (including cysts and polyps)’. Results: As of July 2018, 1293 patients had been enrolled in the study and 983 (76.0%) remained active in the study. Approximately half [n = 637 (49.3%)] of the patients were GH treatment-naïve on study entry. The majority of enrolled patients had multiple pituitary hormone deficiency (n = 1128, 87.2%). A total of 41 on-study malignancies were reported in 33 patients (2.6%; incidence rate 7.94 per 1000 patient-years). The most common cancers were basal cell carcinoma (n = 13), prostate (n = 6), breast, kidney and malignant melanoma (each n = 3). Treatment with Omnitrope® was discontinued following diagnosis of malignancy in 16 patients. The tumors occurred after a mean of 79.4 months of recombinant hormone GH (rhGH) treatment overall. Conclusion: Based on this snapshot of data from PATRO Adults, Omnitrope® treatment is tolerated in adult patients with GH deficiency in a real-life clinical practice setting. Our results do not generally support a carcinogenic effect of rhGH in adults with GH deficiency, although an increased risk of second new malignancies in patients with previous cancer cannot be excluded based on the current dataset.