Pb2175 long term follow-up of maintenance therapy with interefron alpha after autologous hematopoietic stem cell transplant in multiple myeloma patients–single center experience

Background: Maintenance therapy after autologous hematopoietic stem cell transplantation (AHSCT) in multiple myeloma (MM) patients was a matter of debate until recently, when lenalidomide in this setting proved to increase overall survival (OS). Before lenalidomide interferon alpha (IFN) was standard maintenance therapy. Aims: The aim of this analysis was to determine the impact of maintenance therapy after AHSCT on progression free survival (PFS) and OS in MM patients treated at our institution between 1993 and 2014. Methods We performed a retrospective analysis of outcomes of MM patients autografted at our institution between 1993 and 2014. We identified 274 pts. who had PFS at least 6 months posttransplant; median age was 57, range 28‐71, 48% were male. 124 of them received tandem and 150 single AHSCT. Median follow‐up was 62 mo. Posttransplant 200 patients received IFN, 44 thalidomide and 30 no maintenance according to physicians’ choice. Results: Patients receiving IFN had longer 5‐year PFS compared to patients receiving thalidomide or no maintenance (52% vs. 34% vs. 31%, respectively, p < 0.001). OS was best in the IFN group, intermediate in the thalidomide and worst in the no maintenance group (67% vs. 59% vs. 32%, respectively, p < 0.001). The difference was limited to patients receiving tandem transplants. In this group 5‐year PFS was 61% vs. 35% vs 0% (p < 0.001) and OS 85% vs. 67% vs. 65% (p = 0.003) in the IFN, thalidomide and no maintenance group respectively. In patients that received a single transplant 5‐year PFS was 43% vs. 33% vs 36% (p = 0.157) and 5‐year OS 70% vs. 75% vs. 54% (p = 0.06) in the IFN, thalidomide and no maintenance group respectively. Summary/Conclusion: Our results indicate that maintenance therapy has beneficial effects on OS and PFS in MM patients treated with tandem, but not single AHSCT. IFN is superior in this setting to thalidomide and could be considered as a treatment option when lenalidomide is not available.