Incidence of second primary malignancies (SPMs) in patients with multiple myeloma (MM) receiving anti-CD38 monoclonal antibodies (mAbs): A systematic review and meta-analysis.

e24078 Background: The addition of anti-CD38 mAbs, daratumumab and isatuximab, to standard anti-myeloma regimens have drawn scrutiny towards long-term safety concerns, including the risk of SPMs. ICARIA-MM study reported SPMs in 3.9% patients (pts.) in the Isatuximab, pomalidomide and dexamethasone (Isa-Pd) arm compared to 0.7% in the Pd arm. We hypothesized that exposure to anti-CD38 mAbs could potentially increase risk of SPMs due to prolonged immunosuppression. An assessment of this association is warranted, given the improved life expectancy and growing prevalence of pts. with MM. Methods: We performed a meta-analysis on data obtained from RCTs published between January 2005 and April 2022 that compared anti-CD38 mAb-based regimens to other standard anti-myeloma regimens (control) in pts. with newly diagnosed or relapsed/refractory (r/r) MM. Total number of SPMs (including categories) were extracted for pts. in both groups. Malignant melanomas were included under solid SPM category. Binary outcome data were analyzed using fixed-effect Peto method. Treatment effect estimates were expressed as odds ratio (OR) and 95% confidence interval (CI). I 2 > 50% indicated substantial heterogeneity. Results: 10 RCTs involving 4980 pts. were included, with 2824 (57%) and 2156 (43%) pts. randomized to the anti-CD38 mAb and control arms, respectively (Table). Overall, 191 and 112 SPMs were reported in the anti-CD38 mAb and control arms, respectively. At a median follow-up of 35.3 months, anti-CD38 mAb exposure was associated with an increased risk of developing SPMs compared to control (6.8% vs. 5.2%; OR: 1.53 [95% CI: 1.20-1.95]; I 2 = 0%). Non-melanoma cutaneous cancers were the most common, and higher in the anti-CD38 mAb vs. control arms (92 versus 47; OR: 1.77 [95% CI: 1.25-2.51]; I 2 = 0%). The increase in solid cancers (including melanoma) (OR: 1.28 [95% CI: 0.85-1.95]) and hematologic SPMs (OR: 1.86; [95% CI: 0.81-4.27] was not significant. On sensitivity analysis, the total number of SPMs were higher in the anti-CD38 mAb arm vs. control arm, regardless of the presence of immunomodulatory drugs in combination regimen. Conclusions: This meta-analysis shows an increased risk of SPMs in pts. with MM exposed to daratumumab or isatuximab, particularly that of non-invasive cutaneous tumors. This association should be further investigated in real-world settings using large databases. [Table: see text]