Clinically Relevant Outcomes With Romiplostim in Patients With Solid Tumors and Persistent Chemotherapy Induced Thrombocytopenia

Thrombopoietin receptor agonists (TPO-RAs), such as romiplostim, are commonly utilized to facilitate timely platelet recovery and administration of chemotherapy in patients with cancer and chemotherapy-induced thrombocytopenia (CIT). However, there are limited data on the effect of TPO-RAs on clinically important outcomes. A target trial emulation study was implemented to assess the effects of romiplostim in patients with solid tumors and persistent CIT, compared to controls. Patients were exact-matched on chemotherapy, cancer type, degree of thrombocytopenia, and 1:1 propensity-score-matched on clinical/laboratory variables on Day 1 of romiplostim treatment or quasi-index date for controls. Study outcomes included overall survival over 24 months and venous thromboembolism (VTE) at 6 months. This study included 165 romiplostim-treated patients and 165 controls. Baseline characteristics were well-balanced. The median age was 61 years and 52% were female. The median romiplostim duration was 1.38 months. Median overall survival was 13 months (95% CI: 9.9-23) in the romiplostim group and 9.5 months (95% CI: 7.1-14.0) in controls (hazard ratio [HR] 0.86 [95% CI: 0.65-1.13]). There was a numerical improvement in survival with romiplostim (0.80 [95% CI: 0.60-1.06]) which was statistically significant in the subgroup of patients with metastatic disease (HR 0.70 [95% CI: 0.52-0.95]). The 6-month cumulative incidence of VTE was 10.0% (95% CI: 6.3%-16.0%) in the romiplostim group and 8.0% (95% CI: 4.5%-13.0%) in controls (HR 1.31 [95% CI: 0.64-2.70]), with death as a competing risk. In conclusion, these results support the safety of romiplostim in CIT with observed numerical improvement in overall survival at 2 years.