Maintenance with Weekly Carfilzomib in Elderly Newly Diagnosed Multiple Myeloma (IFM 2012-03)

Background. Continuous therapy, such as maintenance approach, appears to be a major therapeutic change in multiple myeloma, improving response rate and overall survival. Novel agents widen the range of treatment options, still Lenalidomide (IMiD) is widely used in this indication. Even though usually well tolerated, it remains a daily treatment, and can lead to some side effects on a long term basis. Carfilzomib, a second generation PI, allows interesting response rate and prolonged survival, with manageable adverse events. Nevertheless, only few clinical trials focused on its use in maintenance rather than in first or second line treatment. We therefore thought to study the role of 1 year Carfilzomib exposure following KMP IFM 2012-03.

Methods. IFM 2012-03 is a multicenter phase I study for eNDMM (patients aged 65 years old and more) that determined the maximal tolerated dose of weekly carfilzomib, associated with melphalan and prednisone (KMP), at 70mg/m². The following results will concern the second phase of the study using intravenous Carfilzomib monotherapy in maintenance. K was administered at 36 mg/m² for 13 cycles on an every 2 weeks schedule.

Results. Thirty eNDMM were recruited in IFM 2012-03. Median age is 75, with 56% R-ISS 2 or 3 and 11% high-risk cytogenetic. With K weekly from 36 to 70mg/m², ORR is reported at 93.3%, including 46.7% ≥CR ; median PFS is 35.8 months and median OS was not reached.

Twenty-two (73%) patients started K maintenance and 16 (73%) completed it. Four patients progressed and 2 stopped for AEs (renal amylosis, sensory neuropahty) during the maintenance phase. At maintenance completion, 50% were ≥CR. From the start of maintenance, in landmark analysis, median PFS is 28.1 months and the estimated 36-months OS approximately 70%. Moreover, 3 patients (14%) improved their responses during maintenance.

Conclusion. Carfilzomib monotherapy can be used safely in maintenance for 1 year in eNDMM, including for patients above 75 years. K maintenance may lead to deep response rate, certainly a most relevant prognostic factor for prolonged survival. Therefore, Carfilzomib maintenance, characterized with a simple administration modality, might be considered as an alternative to Lenalidomide and integrate the armamentarium of prolonged therapy in eNDMM. Further studies should still bring additional information in order to confirm our results.