Biosimilar, Innovator Romiplostim Comparably Safe and Effective

Noninferiority with comparable efficacy and safety between biosimilar romiplostim (ENZ110) and innovator romiplostim (Nplate) in patients with chronic immune thrombocytopenia (ITP) was displayed in Indian Journal of Hematology and Blood Transfusion.

This study was conducted because biosimilar romiplostim can be made available for patients with ITP at a low cost and can be helpful in providing the best therapy. Romiplostim is approved by the FDA for ITP, and biosimilars of biologics like romiplostim may have the ability to lower health care–related costs.

“The biosimilar of Romiplostim, ENZ110, would accomplish the unmet need in the niche Indian market in patients with ITP; its introduction would be an effective treatment option due to its affordability,” said the study authors.

First, researchers aimed to determine the efficacy and safety of ENZ110 compared with Nplate with respect to platelet response in patients with chronic ITP. Next, those with chronic ITP aged 18 to 65 years were enrolled in a study and randomized to either receive ENZ110 or Nplate in a 1:1 ratio for a treatment timeline of 12 weeks. After the treatment period ended, patients were followed up with for 1 week to review the platelet response and to check for adverse events.

Over the 12 weeks, platelet response of > 50 x 10⁹/L was achieved in 85.3% patients treated with ENZ110 and 75.0% patients treated with Nplate in per protocol population.

“In the intent-to-treat population, 83.8% patients with ENZ110 and 76.9% patients with Nplate achieved a platelet response of > 50 x 10⁹/ L,” explained the researchers.

In terms of safety, 129 treatment-emergent adverse events were reported by 34 (65.4%) individuals. Serious AEs were reported by 5 people, 1 of which led to death. Of the 129 TEAEs, 83 might have been associated with the study medication, 4 AEs were likely related, and 42 AEs were unlikely to be related. In the ENZ110 group, 111 AEs were recorded in 26 (66.7%) patients and 18 AEs were seen in 8 (61.5%) patients in the Nplate group. The rates of patients having at least 1 AE were similar between groups.

Despite these reported AEs, no significant differences were seen in the incidences of TEAEs between the treatment groups. The reported AEs were anticipated and constant with reference to Nplate. Treatment-emergent anti-drug antibody was identified in 2 patients (5.71%) from the ENZ110 group and 1 patient (9.09%) from the Nplate group, which was consistent with the Summary of Product information.

Additionally, since the study used a 1-mcg/kg dose of ENZ110, there was no statistically significant difference seen from baseline to week 12 for hematology and biochemistry laboratory parameters in both treatment groups.

Concerning pharmacokinetic assessment, most of the samples were reported below the lower limit of quantitation (40 pg/mL) of the assay. Therefore, the statistical analysis was not completed.

Even though romiplostim is an approved treatment for ITP, because of cost constraints in India, most people prefer immunosuppression therapy. The biosimilar of romiplostim, ENZ110, would come as a significant relief to patients with ITP since its affordability would fulfill unmet needs in patients who need the best treatment.

“This study established noninferiority, along with comparable safety and immunogenicity between biosimilar romiplostim and innovator romiplostim in patients with chronic ITP,” concluded the study authors.

Reference

Chandrakala S, Toshniwal M, Halvawala M, et al. Efficacy and safety of biosimilar romiplostim versus innovator romiplostim in patients with chronic immune thrombocytopenia. Indian J Hematol Blood Transfus. 2023;39(3):435-441. doi:10.1007/s12288-022-01602-5