Adverse Cytogenetics, with or without Trisomies, in Patients Undergoing High Dose Therapy for Multiple Myeloma and Impact of Post-Transplant Maintenance Therapy

Background FISH abnormalities including t(14;16), t(14;20), t(4;14) and the loss of P53 remain a common mechanism for classifying patients (pts) with newly diagnosed multiple myeloma (MM) as adverse risk. In contrast, trisomies in MM are associated with superior outcomes and may ameliorate the negative prognostic significance conferred by adverse FISH abnormalities. High dose therapy (HDT) consisting of high dose melphalan and autologous stem cell transplantation with consideration of maintenance therapy is a common treatment strategy for transplant eligible MM pts. However, there is limited information regarding the impact of various cytogenetic abnormalities, alone or in combination with trisomies, in the context of HDT, and the efficacy of maintenance approaches in the novel agent era. Aim To determine the clinical significance of FISH abnormalities in MM pts undergoing HDT and subsequent consideration of maintenance therapy in recent years. Methods We retrospectively examined a cohort of all pts with MM who underwent first HDT at Mayo Clinic Rochester between 2008 and 2012. Medical records were reviewed under IRB approval in accordance with the principals of the Helsinki declaration. FISH results were obtained from within 6 months of diagnosis (Dx), and if unavailable pts were excluded. Pts were considered for maintenance therapy following response assessment by their treating hematologist, typically around day 100 following HDT, and were categorized based on the intent of that discussion; length of maintenance and dose reductions were not evaluated. PFS and OS were calculated from date of transplant and OS was also estimated from Dx. Timing of HDT was restricted to within one year of MM Dx (early HDT). Results 300 pts had available FISH and underwent early HDT. Median age at dx was 60 (23-75), and median follow up from Dx was 40 months (7.5-90) with 229 (76%) alive at time of analysis. The median time to HDT from Dx was 5.8 months (95% CI 5.4-8.0). At the time of HDT 249 pts (83%) were in a partial response or better. Overall, 73 pts (24%) had adverse risk FISH from dx as described, 154 pts (51%) had at least one trisomy, and 32 pts (10.7%) had a concomitant adverse FISH abnormality and a trisomy. Of all pts, 112 (37%) received maintenance therapy of some sort, most commonly single agent lenalidomide (n=67 pts) or bortezomib (n=36). Of the 73 pts with adverse FISH, 54 (74%) received maintenance therapy following initial HDT compared with 58 of 227 pts (26%) with non-adverse FISH. Among pts with adverse FISH, median PFS and OS was 21 months (95% CI 16-24) and 57 months (95% CI 41-NR) respectively, compared with 24 months (95% CI 21-26) and not met respectively for pts with no adverse FISH (p =0.08 and p=0.04). The OS from Dx was 63 months (95% CI 46-NR) and not met, respectively for pts with adverse FISH and no adverse FISH (p=0.04). Among adverse FISH pts, PFS following initial HDT was improved with any maintenance therapy (23 months (95% CI 18-33) versus 13 months (95% CI 6-22), p=0.0016). OS was not statistically different among pts with adverse FISH whether or not they received maintenance therapy, both from date of HDT as well as from Dx. For pts with non-adverse FISH at Dx similar findings were observed, with an increase in PFS following HDT with any maintenance therapy (30 months (95% CI 23-48) versus 22 months (18-24)), without a difference in OS. Further analysis of the group of pts with adverse FISH status revealed the PFS benefit seen with maintenance therapy was greatest for a subgroup of pts with concomitant trisomies (29 months (95%CI 18-38) versus 14 months (95%CI 8-16) p=0.0003) as compared to pts with adverse FISH without concomitant trisomies (19 months (95%CI 13-35) versus 12 months (95% CI 3-24) p=0.204) (figure 1). However, OS either from HDT or Dx did not differ for pts with adverse FISH with or without concomitant trisomies regardless of maintenance status. Conclusions Our data support an improvement in PFS with maintenance therapy following initial HDT amongst adverse risk FISH MM pts, however no OS benefit was observed with maintenance therapy irrespective of FISH status. Among pts with adverse FISH, maintenance strategies improve PFS for pts with a concomitant trisomy. No PFS benefit was seen with maintenance therapy in pts without concomitant trisomies. Future trials of maintenance therapy post HDT should consider evaluating and reporting on the subgroup of adverse FISH pts with concomitant trisomies. Disclosures Kumar:Janssen: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Sanofi-Aventis: Consultancy, Research Funding; Onyx Pharmaceuticals: Consultancy, Research Funding; Millennium: The Takeda Oncology Co.: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Skyline Diagnostics: Membership on an entity9s Board of Directors or advisory committees.