Elotuzumab-based maintenance therapy following autologous stem cell transplant in multiple myeloma deepens post-transplant responses

Background: Post-transplant maintenance provides progression-free survival benefit in multiple myeloma (MM). Here we report our institution's experience with elotuzumab-based maintenance following autologous stem cell transplant. Methods: We retrospectively evaluated the outcomes of MM patients who were started on elotuzumab-based maintenance (elotuzumab/lenalidomide/dexamethasone, elotuzumab/bortezomib/dexamethasone, or elotuzumab/bortezomib/methylprednisolone) following transplant (N = 7). Baseline characteristics, treatment response, survival, and adverse events were reviewed. Results: Median age was 68 (56-81) years at the time of transplant, and median lines of induction therapy was 2 (1-6). Three patients (42.9%) had high-risk cytogenetics and five (71.4%) had stage II or greater disease at diagnosis. At a median follow-up of 24 months (12-50), five patients (71.4%) had improvement of quality of response, with a combined CR or VGPR rate increasing from 57.1% to 100% (CR = 3, VGPR = 4). All patients were alive without relapse or progression at the time of this analysis. Grade 3-4 adverse events were observed in three (42.9%) patients. None of the patients discontinued the treatment due to intolerance. Conclusions: Our study demonstrates that elotuzumab-based maintenance may deepen response post-transplant in MM and can be safely administered even in older patients. Given its unique action and rare side effects, further studies of elotuzumab in the post-transplant setting are warranted.