In a retrospective analysis of real-world patients with relapsed/refractory multiple myeloma (RRMM), depth of response corresponded to overall survival (OS) and time to next treatment (TTNT).1 The analysis was published online December 28, 2018.

A total of 139 patients from 14 clinical trials were included in the analysis. Patients were treated between 2009 and 2016 and received a range of investigational agents: monoclonal antibodies, second- and third-generation proteasome inhibitors, immunomodulatory drugs, and histone deacetylase inhibitors.

The overall response rate (ORR) was 73.7%, with 10.9% of patients having a stringent complete response (sCR) and 23.4% having a very good partial response (VGPR). Patients who received 1 prior line of therapy achieved a higher ORR than those who received more than 1 prior line (90.3% vs 60%; P < .001).

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International Staging System (ISS) stage correlated with longer OS. Patients at ISS stage 1 had a longer median OS (64.5 months) than those at ISS stage 2 (21.2 months) or ISS stage 3 (14.8 months; P < .001).

Depth of response to therapy also correlated with longer OS. Patients who demonstrated a complete response (CR), sCR, or a VGPR had a longer a median OS (64.5 months) than those who experienced a partial response (PR; 29.9 months), stable disease (SD)/minimal response (MR; 12.4 months), or progressive disease (3.5 months; P < .001).

The median TTNT was longer in patients with ISS stage 1 (13.3 months) than patients with ISS stage 2 (hazard ratio [HR = 2.15; P < .001) or 3 (HR=2.3; P < .001). TTNT was also associated with depth of response (HR, 2.4; P = .02 for sCR/CR vs PR; HR 6.5, P <  .001 for sCR/CR vs MR/SD).

“In conclusion, in a heterogeneous group of real-world RRMM patients treated over 8 years on clinical trials, ISS at time of relapse, and depth of response to subsequent therapy, have meaningful impact on OS and TTNT, independent of the number of prior lines of therapy,” the study authors wrote.

Reference

  1. Chan EHL, De-Silva D, Lin AHF, et al. Clinical benefit of depth of response for relapsed/refractory multiple myeloma patients treated on clinical trials: retrospective analysis from two tertiary centres [published online December 28, 2018]. Br J Haematol. doi: 10.1111/bjh.15743