Camrelizumab Plus Gemcitabine, Vinorelbine, and Pegylated Liposomal Doxorubicin in Relapsed/Refractory Primary Mediastinal B-Cell Lymphoma: A Single-Arm, Open-Label, Phase II Trial

Purpose: Patients with relapsed/refractory primary mediastinal B-cell lymphoma (rrPMBCL) represent a particularly challenging population to treat, with few life-saving treatment options in the context of a dismal prognosis.

Patients and Methods: In this open-label, single-arm, phase II study, the safety and efficacy of combined regimen of chemotherapy consisting of gemcitabine, vinorelbine, and pegylated liposomal doxorubicin (GVD) plus anti-PD-1 antibody camrelizumab was assessed in rrPMBCL. Patients received chemo-immunotherapy every 3 weeks until the second confirmed complete response (CR) or up to 12 cycles, followed by camrelizumab monotherapy for up to 1 year. The primary endpoints were objective response rate (ORR) and safety.

Results: Twenty-seven response evaluable patients were enrolled, who received a median of three first-line therapies, 59% with bulky disease. The ORR was 74%, including 56% with a CR. A median time of 1.7 months to response was observed, with 78% exhibiting tumor shrinkage at the first evaluation. After 24.8 months median follow-up, the median duration of response was not reached, with a 65% 2-year estimated response rate. Thirteen responders remained in sustained complete remission. Estimated 24-month progression-free survival and overall survival rates were 48.2% and 81.5%, respectively. Any grade and grade 3 treatment-related adverse events (AE) occurred in 93% and 33% of patients, respectively; with no grade 4 or 5 AEs. Baseline levels of IL10, IFNγ, and soluble Fas were associated with objective response.

Conclusions: Camrelizumab plus GVD chemotherapy offers a potent option as life-saving chemo-immunotherapy with promising efficacy and a manageable safety profile for patients with rrPMBCL, especially with bulky aggressive disease.