Purpose: Chemotherapy-induced thrombocytopenia (CIT) can cause delay or reduction in subsequent courses of chemotherapy. Here, we report on a series of 20 patients who had protracted CIT and were treated with romiplostim, a thrombopoietin receptor agonist.
Patients and methods: We performed a retrospective review of the use of romiplostim for dose-limiting CIT at Memorial Sloan-Kettering Cancer Center from 2010-2012. Romiplostim was initiated at 1-2 mcg/kg weekly, with dose escalation by 1 mcg/kg per week until recovery of platelets (≥ 100 × 10(9)/L). If patients resumed chemotherapy, weekly romiplostim was continued.
Results: Romiplostim improved platelet counts in all 20 patients. In 19 of 20 patients, platelet counts of ≥ 100 × 10(9)/L were achieved. The mean dose of romiplostim to achieve adequate platelet recovery was 2.9 mcg/kg (range 1.0-5.1). Sixteen patients achieved platelet recovery by 2 weeks. Fifteen patients resumed cytotoxic chemotherapy with continued romiplostim support and 14 tolerated at least two subsequent cycles of chemotherapy, on schedule, without recurrence of dose-limiting CIT. Sepsis prevented continued chemotherapy in one patient. No resistance to romiplostim was observed. Three deep vein thromboses (DVT) were observed; one of which was a recurrent DVT in a patient who had previously experienced a DVT and was off anticoagulation. Three DVTs within 20 patients is within the anticipated thrombosis rates of patients with active cancer on chemotherapy.
Conclusion: Romiplostim resulted in improvement in platelet counts, allowing resumption of chemotherapy without recurrence of dose-limiting CIT. No treatment-related toxicity was observed, but this would need to be confirmed in a larger, prospective trial. Our series differs from prior studies in that we selected only those patients who had already demonstrated persistent thrombocytopenia, and we continued weekly romiplostim during chemotherapy. Romiplostim may be a safe and effective treatment for CIT.