Efficacy of Daratumumab in 34 Patients with Newly Diagnosed Multiple Myeloma in Real World Study

Objective: To observe the efficacy and safety of daratumumab (Dara) for newly diagnosed multiple myeloma (NDMM) in the real world.

Methods: The clinical data of 34 patients with NDMM treated with Dara in 3 medical centers in Shandong Province was collected.Treatment options included 15 Dara-Vd, 5 Dara-d, 4 Dara-Rd, 4 Dara-RVd, 3 Dara-ICd, 2 Dara-VCd and 1 Dara-Id. The efficacy was evaluated and the classification of M protein expression, cytogenetics, creatinine clearance and minimal residual disease (MRD) were gathered. NGF MRD-negative was used as the intermediate endpoint of survival prediction to evaluate the related influencing factors.

Results: There were 19 male among the 34 NDMM patients and 21 cases were <65 years. 9 cases completed 2 treatment cycles, 11 completed 4 treatment cycles and 14 completed 6 treatment cycles. The univariate association between efficacy (sCR, CR,VGPR, PR, SD and PD) and the clinical feature showed a statistically significant association between ECOG score and efficacy ( P=0.002).The best response for CR is 38.2% (13/34)) with 0 score, 8.8% (3/34) with 1 score, 5.9% (2/34) with 2 score ,while none with 3 score. As the efficacy was divided into 2 groups (CR and other effects), the CR rate after 2,4, and 6 cycles showed a linear trend (Fisher test P=0.025, linear trend test=7.062, P=0.008). COX multivariate analysis showed the achievement of NGF MRD-negative was associated with increased cycle number, in which 8.8% (3/34) after 2 cycles, 24% (6/25) after 4 cycles and 35.7% (5/14) after 6 cycles, while no association with other factors as gender, ISS stage and cytogenetics. We observed that the incidence of hematological adverse reactions above grade 3 was 20.5%(7/34), mainly neutropenia and thrombocytopenia. Other non-haematological adverse reactions were infection (44.1%) and peripheral edema (41.2%).

Conclusion: Although efficacy was limited in high ECOG scores, Dara based regimen regardless of gender, age, disease stage was a good choice for NDMM in our observation. With the increase of treatment cycles, deep remission was more outstanding with tolerable side effects.