Tolerability in Patients with Multiple Myeloma Treated with Daratumumab: A Systematic Review and Meta-Analysis of Phase III Randomized Controlled Trials

Introduction:

Multiple myeloma, which accounts for 1% of all cancers, is a hematologic cancer in which clonal plasma-cell proliferation leads to complications and death. Over the recent years, it has shown that the introduction of novel agents, including daratumumab and the incorporation of proteasome inhibitors and immunomodulatory drugs has improved outcomes in patients with multiple myeloma. Daratumumab is a human, CD38-targeting, IgG1κ monoclonal antibody with direct antitumor effects and an immunomodulatory component and has recently shown to improve survival in patients with multiple myeloma. However, there are considerable safety concerns. The purpose of our study is to determine the risk of TD and deaths due to treatment-related adverse events (TRAE) in patients with multiple myeloma treated with daratumumab.

Methods:

We systematically conducted a comprehensive literature search using MEDLINE, EMBASE databases and meeting abstracts from inception through June 2019. Phase III RCTs utilizing daratumumab in patients with multiple myeloma were incorporated in the analysis. Mantel-Haenszel (MH) method was used to calculate the estimated pooled risk ratio (RR), and risk difference (RD) with 95% confidence interval (CI). Heterogeneity was assessed with Cochran's Q- statistic. Random effects model was applied.

Results:

Five phase III RCTs with a total of 3,547 patients with multiple myeloma were eligible. Studies compared daratumumab (D) + bortezomib (V) + melphan (M) + prednisone (P) vs VMP, D + lenalidomide (R) + dexamethasone (d) vs Rd, DVd vs Vd, DVd + thalidomide (T) vs VTd and DRd vs Rd. The randomization ratio was 1:1 in all studies. Daratumumab was utilized in relapsed and refractory multiple myeloma in the POLLUX study (n= 564) and the CASTOR study (n= 480) and as first-line treatment for patients with multiple myeloma in the ALCYONE study (n= 700), the CASSIOPEIA study (n= 1085) and the MAIA study (n= 737). The I² statistic for heterogeneity was 39, suggesting some heterogeneity among RCTs. TD due to TRAE was noted in 120 (6.77%) vs 179 (10.08%) in control group with RR of 0.68 (95% CI: 0.51 -0.91; P = 0.0009) and RD of -0.03 (95% CI: -0.06 to 0.00; P = 0.02). TD due to infection/ pneumonia was reported in 0.95% vs 0.73% in control group (RR, 1.19; 95% CI: 0.42 -3.34; P = 0.75). Treatment-related deaths were 64 (3.61%) in daratumumab arm vs 77 (4.34%) in control arm. The pooled RR was not statistically significant at 0.86 (95% CI: 0.59 -1.25; P = 0.43).

Conclusions:

The rate of discontinuation of trial treatment due to adverse events was significantly lower in the daratumumab group (6.77%) than in the control arm (10.08%) with RR of 0.68, favoring daratumumab combination regimen. Furthermore, there was no significant difference in the treatment discontinuation due to pneumonia or infection and treatment-related deaths due to TRAE in the daratumumab group, compared to control arm.