Efficacy and safety of biosimilar romiplostim in Indian patients with chronic immune thrombocytopenia: A multicentric retrospective study

Context and Aims: To evaluate the efficacy and safety of biosimilar romiplostim in Indian patients with immune thrombocytopenic purpura (ITP). Settings and Design: Multicentre, retrospective observational study. Methods and Material: Patients with chronic ITP who received biosimilar romiplostim from July 2019 to March 2020 across 3 major hospitals in Guwahati, India, were included. The study outcomes were the platelet response (platelet count > 50 x 109/L), time to first response, number of dose-limiting events, and the median effective dose. Statistical Analysis Used: Descriptive. Results: Of 32 patients included in this analysis, majority (59.4%) were females. The mean (SD) age was 40.37 (15.79) years, and mean age at ITP diagnosis was 38.53 years. The median number of romiplostim doses were 27.5 (range: 10-42) over a period of 10 months; median romiplostim dose used was 4.2 mu g/kg (range: 2.8-5 mu g/kg). Platelet response was achieved as early as after one week in 9 (28.12%) patients, which continued to increase to 24 (75%) patients after the second, 30 (93.75%) patients after the third and all 32 (100%) patients after four weeks of romiplostim administration. The median platelet count was 161 x 109/L. Dose reduction was done in a total of 21 patients. Thrombocytosis (46.88%), elevated liver enzymes (15.63%) and myalgia (15.63%) were the most common adverse events. Conclusions: Biosimilar romiplostim was effective in achieving and maintaining platelet response without any new safety concerns in Indian adult patients with chronic ITP. The median effective dose of romiplostim required in our patients was lower as compared with the standard prescribed dose.