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. 2025 Jul 24;6(4):e70105.
doi: 10.1002/jha2.70105. eCollection 2025 Aug.

Multicenter Single-Blind Randomized Controlled Trial of the Romiplostim Biosimilar

Anait L Melikyan  1 , Ekaterina A Protsenko  2   3 , Galina N Salogub  4 , Bulat A Bakirov  5 , Igor L Davydkin  6 , Vladislav V Kovalik  2   3 , Mariia L Gefen  2 , Yuliia D Matvienko  2 , Valeria B Saparova  2 , Alexander L Khokhlov  7 , Igor E Makarenko  2   8 , Roman V Drai  2
Affiliations

Multicenter Single-Blind Randomized Controlled Trial of the Romiplostim Biosimilar

Anait L Melikyan et al. EJHaem. .

Abstract

Background: This was a randomized multicenter single-blinded active-controlled equivalence Phase III study evaluating the efficacy and safety of the biosimilar of romiplostim (GP40141) compared to the reference drug Nplate in patients with persistent or chronic immune thrombocytopenia (ITP).

Methods: The study included 136 adult patients randomized 1:1 to receive either the biosimilar or reference drug for 26 weeks. The primary endpoint was the proportion of patients achieving a platelet response (≥ 50 × 109/L) at Week 11. Key secondary endpoints included proportion of patients with durable platelet response, stable response in treatment-naive patients, incidence of bleeding, and rescue therapy usage.

Results: The proportion of patients with platelet response after 10 weeks of therapy was 78% in the test group and 85% in the comparison group. The absolute difference in proportion between groups was -0.06 (95% CI [-0.196, 0.068] and it falls within the equivalence limits [-0.225, 0.225]). The study demonstrated equivalence in the primary endpoint, with no significant differences between the biosimilar and reference drug groups in durable responses rate, bleeding events, or safety profiles.

Conclusions: The results support the biosimilar romiplostim as an equivalent and comparable treatment option to the reference drug for patients with persistent or chronic ITP.

Trial registration: NCT06497036.

Keywords: TPO‐RA; biosimilar; primary immune thrombocytopenia; romiplostim.

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Conflict of interest statement

E.A.P., V.V.K., M.L.G., V.B.S., Y.D.M., I.E.M., and R.V.D. are employees of GEROPHARM. All other authors received honoraria from GEROPHARM for participating in this study.

Figures

FIGURE 1
FIGURE 1
Study flow (FAS—full analysis set, PP‐H—per protocol set for hypothesis testing, SAF—safety set).
FIGURE 2
FIGURE 2
A—Proportion of patients with platelet response on Week 11 (GP40141, N = 68; Nplate, N = 67); B—95% confidence interval for absolute difference between groups.
FIGURE 3
FIGURE 3
A—Proportion of patients with platelet response on Week 11 including subgroup analysis; B—proportion of patients with durable platelet response including subgroup analysis; GP40141, N = 68, N (Cohort 1/2) = 35/33; Nplate, N = 67, N (Cohort 1/2) = 33/34.
FIGURE 4
FIGURE 4
A—Median (with IQR—interquartile range) platelet count on Weeks 0–26 for treatment‐naïve patients (N (GP40141/Nplate) = 35/33); B—Median (with IQR) platelet count on Weeks 0–26 for pretreated patients (N (GP40141/Nplate) = 33/34).
FIGURE 5
FIGURE 5
Kaplan–Mayer curve with time to reach stable platelet response for treatment‐naïve patients.
FIGURE 6
FIGURE 6
Individual plots with platelet numbers during study flow with timing of immune response detection.
See this image and copyright information in PMC

References

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