Ixazomib, Pomalidomide and Dexamethasone (IxaPD) Pan-Oral Regimen in the Treatment of Refractory and Relapsed Multiple Myeloma

Aim To analyze the efficacy and safety of Ixazomib, pomalidomide and dexamethasone (IxaPD) regimen in patients with refractory and relapsed multiple myeloma（RRMM）.

Methods Clinical data of RRMM patients were collected from 5 centers in north China from Jan 2021 to Aug 2023, who were treated by IxaPD regimen for at least two courses. Response, time to next treatment and overall survival were analyzed as end points.

Results A total of 34 patients were enrolled, including 21 in multicenter real-world study and 13 in investigator initiated IxaPD trial (NCT04989140) who were naïve to ixazomib or pomalidomide with previous treatment of 1 to 3 lines. There were 18 males and 16 females with the median age 65.5 (range 41-81) years old. The median duration from diagnosis to enrollment was 31 months (range 1-117), including 23/34 (67.3%) of patients were in first relapse. Thirteen in 24 (54.2%) patients had high-risk cytogenetic abnormalities. Regarding previous history, 20.6% presented renal insufficiency, 3 cases (8.8%) had extramedullary diseases, and 5 cases (14.7%) received autologous hematopoietic stem cell transplantation. After median 5 courses (range 2-24) of IxaPD chemotherapy, the overall response rate (ORR) was 64.7%, with 47.1% VGPR or better. The median time to achieve the best response was 2 months (range 1-6). After a median follow-up of 13 months (range 2-28), 52.9% of patients progressed and the median time to next treatment was 7 months (range 3-21). The mortality rate was 17.6%, and the median overall survival was not reached. In the multivariate analysis, response to first-line induction therapy significantly affected the time to next treatment(P<0.05), while age, first relapse, R-ISS stage, high-risk cytogenetics abnormalities, and renal insufficiency did not impact significantly. Neither did those factors also have significant impact on overall survival. Most of the adverse effects (AEs) were grade 1-2, mainly skin rash, peripheral neuropathy, constipation, diarrhea, edema, arthralgia, herpes zoster, and shortness of breath. Only one case of grade 3 pulmonary infection occurred.

Conclusion The pan-oral IxaPD regimen showed anticipated effect and good tolerance for RRMM patients, especially appropriate for patients achieving deep response in first-line therapy. More patients are being enrolled and update data will be reported.