Newly Diagnosed Myeloma (MM) Patients (Pts) with High-Risk (HR) Cytogenetics By FISH: Is There a Role for Tandem Autologous Stem Cell Transplantation (ASCT)?

Background: Recent analyses have suggested that newly diagnosed multiple myeloma (MM) patients with the high-risk (HR) chromosomal abnormalities del 17p and t(4;14) detected by FISH may benefit from bortezomib (BTZ)-based induction therapy and tandem autologous stem cell transplantation (ASCT) (Sonneveld P et al, J Clin Oncol 2013;31: 3279). At Princess Margaret Cancer Centre, we have offered upfront tandem ASCT for HR pts with del 17p, t(4;14) and/or t(14;16) and now retrospectively review the results of this approach.

Methods: After obtaining Institutional Research Ethics Board approval, we used Princess Margaret Myeloma Database to identify HR MM pts who underwent tandem ASCT between June 2005 and January 2015. We performed a retrospective chart review to investigate the survival outcome of this group of patients.

Results: Between 06/05 and 01/15, 52 HR pts underwent tandem ASCT at Princess Margaret Cancer Centre. 21 had del 17p, 20 had t(4;14), 5 had t(14;16), 3 had both t(4;14) + del 17p and 3 had both t(14;16) + del 17p. Median age was 56.5 yrs (range 31-71); 34 were male. ISS stage was I in 12, II in 15, III in 12 and N/A in 13 pts. The majority (42 pts) received BTZ-based induction therapy which consisted of CyBorD in 38; 11 pts required a 2^nd regimen before ASCT. The median time from diagnosis to 1^st ASCT was 6.7 mos (range 4.8 -45.7) and the median time between transplants was 3.7 mos (range 0.9- 6.6); 30 pts received lenalidomide (len) between ASCTs to prevent early relapse. All but 2 pts (96%) received maintenance therapy after the 2^nd ASCT which included thalidomide in 7 (13%), len +/- steroids in 39 (75%) and BTZ +/- len in 4 (8%) of all pts. Thirty-six (69%) received both BTZ-based induction and len maintenance after the 2^nd ASCT. No transplant-related deaths occurred. Median follow-up is 26.3 mos (range 9.1 to 104.3).

The median overall survival in all 52 pts from diagnosis was 31.1 mos (range 11.9 to 110.8) with a median PFS of 24.0 mos (9.1 to 83.6); median survival after progression was only 8.2 mos (0.1-62.8) mos in the 16 pts who relapsed after the 2^nd ASCT.

Conclusions: 1) MM pts with HR cytogenetics, particularly those with t(4;14), have a short PFS and OS after tandem ASCT; 2) even following BTZ-based induction therapy and len maintenance, outcomes with tandem ASCT are suboptimal in HR pts; 3) further investigations are necessary to identify novel strategies for the management of HR MM in the era of modern therapeutic agents.