Association between complete response and outcomes in transplant-eligible myeloma patients in the era of novel agents

ObjectivesAchieving complete response (CR) has been linked to improved progression-free (PFS) and overall (OS) survival in myeloma. A meta-analysis was conducted to investigate whether this holds true in the era of novel agents (bortezomib, lenalidomide, thalidomide). MethodsA total of 24 studies in newly diagnosed patients undergoing autologous stem cell transplantation (ASCT) that reported associations between responses and long-term outcomes (PFS/OS rates post-ASCT by response, or hazard ratios with 95% confidence intervals from Cox models) were identified and analyzed. ResultsAchievement of CR vs. <CR post-ASCT reduced risk of progression/death by 38% [risk ratio (RR): 0.62, P<0.0001]; risk of death was 41% lower (RR: 0.59, P<0.0001). Subgroup meta-analyses showed significant PFS risk reduction with CR post-ASCT with novel (RR: 0.32, P<0.006) and non-novel (RR: 0.72, P<0.0001) agents, and corresponding OS risk reduction with novel (RR: 0.33, P=0.0013) and non-novel (RR: 0.64, P<0.0001) agents. Risk reduction was greater with novel vs. non-novel agents (PFS: P=0.047; OS: P=0.058). ConclusionsAchieving CR during first-line therapy remains important in the novel-agent era; magnitude of association between achieving CR and outcomes appears higher for CR obtained using novel vs. non-novel agents.