Source: Myeloma – Hematology Advisor
Overall survival (OS) and other efficacy outcomes were worse among patients with multiple myeloma (MM) treated with elotuzumab-based regimens after having received daratumumab compared with patients who did not have prior daratumumab, according to a retrospective study published in the Annals of Hematology. However, this decrease in efficacy was somewhat attenuated when elotuzumab was administered 180 days or more after daratumumab or if given nonsequentially.
The multicenter study analyzed data from 127 patients with MM who received elotuzumab from the Kansai Myeloma Forum registry. The primary endpoint was OS and secondary endpoints included time to next treatment (TTNT) and best response.
The median age at diagnosis was 67 and the median age at elotuzumab use was 71. The median number of prior therapies in the daratumumab cohort was 6 (range, 2-13) and was 5 (range, 1-13) in the no daratumumab cohort. Nearly all patients had prior lenalidomide, and 68% and 74% in the cohorts with or without daratumumab, respectively, had prior pomalidomide exposure.
OS was significantly longer in the no-daratumumab cohort, with a 1-year rate of 82.1% compared with 68.7% in the daratumumab cohort (P =.027).TTNT was also longer in the group without prior daratumumab at 188 days compared with 112 days in the daratumumab group (P =.024).
Best response rates were higher in the no-daratumumab group compared with the daratumumab group (P <.01), including the rates of complete response (11.3% vs 2.1%), very good partial response (11.3% vs 4.3%), and partial remission (27.5% vs 12.8%).
Among patients who were treated with daratumumab before receiving elotuzumab, nonsequential use was associated with better outcomes. The 1-year OS was 78.8% in the nonsequential group compared with 50.0% in the sequential group (P =.023). The median TTNT was longer in the nonsequential cohort at 217 days compared with 42 days in the sequential cohort (P =.031).
Best response rates were also higher with nonsequential vs sequential use for very good partial response (3.0% vs 0%) and partial remission (30.3% vs 14.3%), but this was not statistically significant (P =.120).
A longer interval of 180 or more days between the use of daratumumab and elotuzumab was associated with better outcomes than a shorter duration. The 1-year OS was 80.0% in the long interval group compared with 62.5% in the short interval group, but this did not reach statistical significance (P =.084). The mediant TTNT was 204 days and 90 days in the long and short interval groups, respectively (P =.012).
“We demonstrated that OS, TTNT, and best response were worse in the cohort treated with elotuzumab if daratumumab had been given beforehand,” the authors wrote in their report.
Disclosures: Some of the study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of disclosures.