(PA-504) Patterns of Use, Outcomes and Tolerance to Daratumumab in Multiple Myeloma: A Single-centre Retrospective Study

Daratumumab(Dara), a monoclonal antibody targeting CD38, has demonstrated significant efficacy in the treatment of multiple myeloma(MM). However, its high cost restricts its use in many low and middle-income region. This study evaluates the real-world patterns of Dara use, treatment outcomes in MM patients in a resource-constrained setting.

Methods:   

A retrospective observational study was conducted at a tertiary care center. The study included all confirmed adult MM patients who received at least one dose of Dara between Jan. 2018 and Dec. 2024 with available data regarding treatment response. Data collected included patient demographics(age, sex), disease characteristics(e.g. newly diagnosed, relapsed/refractory MM), treatment characteristics (regimen,line of therapy,duration,etc), treatment responses (evaluated per IMWG criteria) and reasons for treatment discontinuation. 

Kaplan-Meier survival analysis was performed to estimate PFS and OS, and Cox regression analysis was employed to identify prognostic factors influencing these outcomes like age,monotherapy vs combination therapy, Dara with IMiD vs. PI and ORR. Statistical significance was set at a p-value < 0.05.

Results:   

A total of 98 patients were included in the analysis, with a median age of 61 years(range:26-81 years), of which 68 were male(69.4%) and 30(30.6%) were female. 83(84.7%) patients had relapsed/refractory multiple myeloma(RRMM) and were started on Dara.15(15.3%) patients were NDMM starting Dara as 1st line of therapy (LOT). Of the RRMM patients, Dara was used in 2nd LOT in 33(33.7%) patients and more than equal to 3rd LOT in 50(51%) patients. The Dara regimens used included Dara with immunomodulators in 52%, proteasome inhibitors in 13.3% and alkylating agents in 4.1%. Quadruplet therapy was used in 26.5% patients, while 4.1% patients received monotherapy. The ORR to Daratumumab-based therapies had 52%. Infusion reactions were noted to be the most common adverse events, reported in 30(30.6%), of which it was Grade 1, 2 and 3 in 17.3%, 8.2%, and 5.1%, respectively. 18(18.4%) patients developed neutropenia, 14(14.3%) patients developed thrombocytopenia and 14 (14.3%) patients developed anemia. 

Median follow-up duration was 16.95(95% CI: 15.5–18.4)months, median progression-free survival (PFS) was 10.97(95% CI: 7.8-14.1)months, and median overall survival (OS) was 27.99(95% CI: 16.5-39.4)months, with higher survival rates observed in patients receiving Dara in the earlier LOT. Cox regression showed that patients who received Dara prior to 3rd LOT had significant survival outcomes compared to ones receiving it in 3rd LOT or later. (p value 0.006,hazard ratio 2.9) 

Conclusions:   

Dara demonstrates meaningful efficacy in RRMM, even in resource-limited setting and optimizing access and early-line use may enhance survival outcomes in real-world practice.