Magrolimab Plus Rituximab With/without Chemotherapy in Patients with Relapsed/Refractory Diffuse Large B-Cell Lymphoma

Patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) ineligible for available salvage therapies have limited options for long-term disease control, necessitating novel treatments. Previously, magrolimab (anti-cluster-of-differentiation-47 antibody) plus rituximab (M+R) demonstrated ability to induce complete responses (CR) in R/R DLBCL. Here we report 3-year follow-up data from this phase 1b/2 study (NCT02953509) assessing long-term safety and efficacy of M+R, and initial safety and efficacy of M+R plus gemcitabine-oxaliplatin (M+R-GemOx), in R/R DLBCL. After magrolimab priming, 4 M+R patient groups received 10-45 mg/kg magrolimab with 375 mg/m2 rituximab; M+R-GemOx patients received 30 or 45 mg/kg magrolimab with 375 mg/m2 rituximab, 1000 mg/m2 gemcitabine, and 100 mg/m2 oxaliplatin. Primary endpoints were treatment-emergent adverse events (TEAEs) and objective response rate (ORR). Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Of 132 patients treated, 99 received M+R and 33 received M+R-GemOx. Most common any-grade TEAEs were fatigue (M+R, 40%; M+R-GemOx, 70%), infusion-related reactions (M+R, 39%), or anemia (M+R-GemOx, 70%). Treatment-related TEAEs led to magrolimab discontinuation in 7% (M+R) and 6% (M+R-GemOx). One death was considered treatment related (M+R-GemOx, colitis). M+R ORR was 24% (CR, 12%), and median DOR was 9.3 months. Median PFS and OS were 1.8 and 9.2 months, respectively. M+R-GemOx ORR was 52% (CR, 39%); 12-month DOR rate was 66.6% (95% CI, 33.1-86.1%). Median PFS and OS were 3.9 months and not reached, respectively. These results demonstrate that M+R with/without GemOx is well tolerated, and M+R-GemOx has clinical activity in patients with R/R DLBCL.