Long-Term Safety and Effectiveness of Thyrotropin Alfa in Japanese Patients: A Post-Marketing Surveillance Study

INTRODUCTION: Real-world evidence of the safety and effectiveness of recombinant human thyroid-stimulating hormone (rhTSH; thyrotropin alfa) in Japanese patients is lacking. METHODS: This was a post-marketing surveillance study that included all Japanese patients who received thyrotropin alfa, either as a supporting diagnostic from January 2009 to December 2016, or as adjunctive treatment for ablation from May 2012 to October 2018. Information was collected on patient demographics, thyroid cancer characteristics, adverse drug reactions (ADRs), scintigraphy, serum thyroglobulin (Tg) testing, and hypothyroidism symptoms. RESULTS: A total of 9268 patients were included in the safety analysis and 9031 in the effectiveness analysis. In the safety analysis set, 3444 patients received thyrotropin alfa as a diagnostic and 5822 received it as treatment. ADRs occurred in 7.1% (n = 660) of patients, including 9.4% (n = 324) of patients who received thyrotropin alfa as a diagnostic and 5.8% (n = 336) of patients who received it as treatment. Nausea was the most common ADR (4.0% of overall safety population). Among patients who received thyrotropin alfa as a diagnostic (n = 1835), the Tg test was positive in 53.6% after the second dose. The scintigram was rated as “readable” in 3023 of the 3054 patients included in this analysis (99.0%). Of the 765 patients who were included in the assessment of response to ablation at 6 months to 1 year after the procedure, 621 (81.2%) were considered to have had “treatment success”. There were no significant differences in the proportions of patients who had hypothyroidism symptoms before the first and after the second dose of thyrotropin alfa. CONCLUSION: In this large post-marketing surveillance study, thyrotropin alfa was well tolerated and showed effectiveness that was comparable to that observed in randomised, controlled trials.