[Efficacy of Pomalidomide in Multiple Myeloma with Extramedullary Disease].

Objective: To investigate the efficacy and safety of pomalidomide in the treatment of multiple myeloma (MM) with extramedullary disease (EMD).

Methods: The clinical data of 40 pomalidomide-based multiple myeloma patients with extramedullary disease admitted to the Department of Hematology, the First Affiliated Hospital of Bengbu Medical College from February 2019 to August 2023 were retrospectively analyzed.

Results: Among the 40 patients, 8 were newly diagnosed with EMD and 32 were refractory/relapsed EMD. There were 21 cases with bone-related extramedullary disease (EM-B) and 19 cases with soft tissue-related extramedullary disease (EM-S). Compared with the EM-B group, the EM-S group exhibited lower LDH levels, an elevation in LDH and a shorter progression-free survival(PFS) (11 months vs 21.5 months, P =0.0363). 32 patients completed 3 courses of treatment, and the short-term efficacy was evaluated. There was no significant difference in the rate of use of 3 or more drugs and ASCT treatment between NDMM group and RRMM group (87.50% vs 93.75%, P >0.05; 25.00% vs 15.63%, P >0.05). Compared with the RRMM group, the overall response rate (ORR) of the NDMM patients was significantly higher (83.33% vs 57.70%, P < 0.05). The deep remission rate (VGPR+CR) of the NDMM group was better than that of the RRMM group (50.00% vs 29.62%, P < 0.05), and the non-response rate (SD+PD) of the NDMM group was significantly lower than that of the R/RMM group (33.33% vs 65.38%, P < 0.05), while the partial remission rate (PR) and mortality rate of the NDMM were not significantly different from those of the RRMM group(P >0.05). With a median follow-up of 26 months, the median PFS was 19 months. Univariate analysis showed that EM-S, high-risk genetic abnormalities, induction therapy did not achieve partial response(PR) or better, and more than 2 lines of treatment failure were associated with shorter PFS. Multivariate analysis showed that the best response to induction therapy did not achieve PR or better, EM-S were an independent adverses prognostic factor for PFS. The results of safety analysis showed that 16 cases had hematological adverse events, including 3 cases of grade 3/4 and 13 cases of grade 1/2. The most common non-hematological adverse events were nausea, vomiting, fatigue and abdominal distension, which were mild and tolerable.

Conclusion: Pomalidomide-based chemotherapy is effective and well tolerated in MM patients with extramedullary disease.