Biosimilar QL0911 Increases, Maintains Platelet Counts in Primary Immune Thrombocytopenia

Credit: Adobe Stock/Катерина Євтехова

Romiplostim (Nplate) biosimilar, QL0911, was well-tolerated and increased and maintained platelet counts in adult patients with primary immune thrombocytopenia (ITP), according to a phase 3 study published in Journal of Translational Internal Medicine.¹

Primary ITP is an autoimmune hemorrhagic disorder in which an isolated reduction in the peripheral blood platelet count occurs without a clear cause. These patients are at a higher risk of bleeding and the condition drastically affects a person’s quality of life. The current first-line treatment strategies for ITP are intravenous high-dose immunoglobulins or corticosteroids, although these treatments are linked to transient efficacy, toxicity, and relapse post-discontinuation. Further, approximately 30% of patients are unable to achieve an initial platelet response and more than 95% experience adverse events, including hyperglycemia, hypertension, acute gastric mucosal lesions, and even femoral head necrosis and osteoporosis.²

“The choice of treatment for patients with ITP requires careful weighing of the benefits and potential risks of these treatment options,” a group of Chinese investigators explained. “Owing to the superior efficacy and safety of romiplostim in ITP and considering the limited treatment options, there is more interest in Nplate biosimilar, although there are still multiple challenges in the development and adoption of biosimilars.”

The randomized, double-blind, placebo-controlled study evaluated the safety and efficacy of the recombinant human thrombopoietin mimetic peptide-Fc fusion protein over 24 weeks at 44 sites in China. Patients were assigned 2:1 to receive a subcutaneous dose of either QL0911 or placebo every week. These doses were initiated at 1 μg/kg and were increased until a maximum dose of 10 μg/kg or a target platelet count of 50 x 109/L was achieved.

Eligible patients were diagnosed with primary ITP for ≥12 months and had received ≥1 first-line ITP treatment with no response or recurrence post treatment or had relapsed after splenectomy. The primary endpoints were safety and the proportion of patients who achieved a platelet response of ≥ 50 × 109/L during 6 of the last 8 weeks of the study.

A total of 216 patients were enrolled between October 2019 and December 2021, with 144 in the QL0911 group and 72 placed in the placebo cohort. Although the baseline demographics and disease characteristics were mostly comparable, more patients in the QL0911 group were female (75.0% vs 59.7%, respectively). The median time from ITP diagnosis to study inclusion was 4.91 years in the QL0911 cohort and 4.15 years in the placebo cohort. The mean baseline platelet counts were (13.07 ± 8.58) × 109/L in the QL0911 group and (13.15 ± 8.31) × 109/L in the placebo group.

A significantly larger proportion of patients receiving the biosimilar achieved a durable platelet response when compared with the placebo group (61.8% vs 0%, respectively; P <.0001). The mean duration of platelet responses was 15.9 weeks in the QL0911 cohort and 1.9 weeks in the placebo cohort and subgroup analyses reported consistent results irrespective of baseline platelet count, concomitant ITP treatment, and baseline splenectomy status.

Regarding safety, the incidence of treatment-emergent adverse events were comparable across arms (QL0911: 91.7%; placebo: 88.9%). The most commonly reported adverse events were upper respiratory tract infections (QL0911: 31.9%; placebo: 27.8%), ecchymosis (QL0911: 28.5%; placebo: 37.5%), and gingival bleeding (QL0911: 17.4%; placebo: 26.4%).

“QL0911… may be a novel treatment option for patients with ITP who have failed or relapsed from first-line treatment in China,” investigators concluded. “Ongoing studies will provide further data on long-term efficacy and safety in such patient populations.”

References

1. ^{Zhou H, Han S, Jin J, et al. Efficacy and safety of QL0911 in adult patients with chronic primary immune thrombocytopenia: A multicenter, randomized, double-blind, placebo-controlled, phase III trial. J Transl Int Med. 2023;11(4):423-432. Published 2023 Dec 20. doi:10.2478/jtim-2023-0106}
2. ^{Cuker A, Liebman HA. Corticosteroid overuse in adults with immune thrombocytopenia: Cause for concern. Res Pract Thromb Haemost. 2021;5(6):e12592. Published 2021 Aug 25. doi:10.1002/rth2.12592}