Romiplostim Treatment Shows Promise for Patients With Thrombocytopenia After Autologous Hematopoietic Cell Transplantation

Results from an Investigator-Initiated, Open-Label, Single-Arm Pilot Study

A pilot study published in Blood Advances indicated that romiplostim, a thrombopoietin receptor agonist, enhanced platelet recovery to normal values after day 15 plus among patients with multiple myeloma (MM) or lymphoma experiencing thrombocytopenia after receiving autologous hematopoietic cell transplantation (auto-HCT). However, romiplostim treatment did not significantly shorten the duration and depth of the platelet nadir among this group. 

Michael Scordo, MD, Memorial Sloan Kettering Cancer Center, New York, New York, and coauthors stated that there were “no standard treatments to prevent or hasten the recovery from severe conditioning-regimen–induced thrombocytopenia occurring after autologous hematopoietic cell transplantation.” Therefore, the study authors conducted this study to "enhance platelet recovery in patients with multiple myeloma or lymphoma undergoing auto-HCT.” 

The primary endpoint was the number of days requiring platelet transfusions or with grade 4 thrombocytopenia after transplantation. Secondary endpoints included the number of platelet transfusions given during auto-HCT admission, time to platelet engraftment, length of auto-HCT stay, and adverse events associated with the treatment. 

A total of 59 evaluable study participants were enrolled in this study, including 58 patients undergoing their first auto-HCT, and 1 undergoing a 2nd auto-HCT. All patients were administered romiplostim weekly starting from day 1 post-auto-HCT and continuing until platelet count recovery was >50 × 109/L without transfusion. The study authors compared the outcomes of romiplostim-treated patients with a matched cohort of retrospective romiplostim-naive patients (n = 853). The study results found that romiplostim-treated patients did not show significant differences from romiplostim-naive patients in terms of the median number of days of grade 4 thrombocytopenia or days requiring transfusions, time to platelet engraftment, and number of platelet transfusions during the auto-HCT phase. 

Notably, the romiplostim-treated cohort demonstrated an enhanced platelet recovery to normal values after day 15 plus. Multivariable analyses of matched cohorts showed that romiplostim treatment was associated with higher platelet counts, with an average increase of 0 × 109/L (95% confidence interval [CI], 14 to 67; P = .003) and 118 × 109/L (95% CI, 84 to 152;  P < .001) at days +21 and +30, compared to patients not receiving romiplostim. Low-risk pulmonary embolism was observed in 1 patient with MM and was the only adverse event considered possibly attributed to romiplostim. 

As endpoints were met, Dr Scordo and coauthors concluded, “Romiplostim showed promising activity and safety after auto-HCT, but the improvement in platelet counts occurred later than the goal of shortening the duration and depth of the platelet nadir.”

Source: 

Scordo M, Gilbert LJ, Hanley DM, et al; Open-label pilot study of romiplostim for thrombocytopenia after autologous hematopoietic cell transplantation. Blood Adv 2023; 7 (8): 1536–1544. doi:10.1182/bloodadvances.2022007838