A phase II, single-arm study of romiplostim N01 for cancer treatment–induced thrombocytopenia in leukemia patients.

6550 Background: Cancer Treatment-Induced Thrombocytopenia (CTIT) poses a significant challenge in leukemia treatment, increasing bleeding risk and potentially disrupting therapy. Romiplostim N01 is recommended for CTIT but lacking specific clinical data in leukemia patients. This study evaluates its efficacy and safety in this population. Methods: This is a multi-center, single-arm, phase II study conducted from February 2025 to February 2027. We plan to enroll 97 adult patients (18 - 75 years) with leukemia who developed CTIT (platelets < 50×10⁹/L) after antitumor therapy. Patients received subcutaneous Romiplostim N01 at a starting dose of 5 µg/kg once weekly for up to 8 weeks. The primary endpoint is the proportion of patients achieving platelet recovery (≥ 50×10⁹/L) after two week. Secondary endpoints include response rate within 7 days, median time to platelet recovery (≥ 50×10⁹/L and ≥ 100×10⁹/L), platelet transfusion requirements, and safety. Results: As of January 27, 2026, a total of 49 subjects were enrolled (18 males, 31 females) with a median age of 57 years (range, 17–75). Primary tumor types included acute myeloid leukemia (AML, n=40), acute lymphoblastic leukemia (ALL, n=7), mixed phenotype acute leukemia (MPAL, n=1), and myelodysplastic syndromes (MDS, n=1). All patients received standard chemotherapy and had an ECOG performance status of 0–2 at enrollment; 35 of 49 patients had an ECOG score of 0–1. All subjects received Romiplostim N01 (5 µg/kg/week): 13 subjects received one dose, 14 received two doses, and 22 received ≥ 3 doses. The median baseline platelet count was 15×10⁹/L (range, 1–49×10⁹/L). 40.8% (20/49) of patients achieved a response within 7 days. 23 subjects (46.9%, 23/49) achieved the primary endpoint (platelet count ≥ 50×10⁹/L) within two weeks. The median time to platelet recovery ≥ 50×10⁹/L was 7 days (95% CI, 6–9). A total of 21 patients achieved a platelet count of ≥100×10⁹/L; the median time to recovery was 13 days (95% CI, 10–22). The median platelet transfusion dose was 2.0 units (95% CI, 1–3). Adverse events were mild to moderate, most commonly infections. No treatment-related serious adverse events (SAEs) were reported. Conclusions: Preliminary findings suggest Romiplostim N01 may be effective in promoting platelet recovery with a manageable safety profile in leukemia patients with CTIT. Final results will provide further evidence for its clinical application. Clinical trial information: NCT06898983 .