Background

Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy has been shown to have activity in patients with relapsed or refractory multiple myeloma. Reports have suggested that a small subgroup of less differentiated myeloma clones express CD19 and anti-CD19 CAR T-cell therapy has shown activity in some of these patients. We aimed to assess the activity and safety of a combination of humanised anti-CD19 and anti-BCMA CAR T cells in patients with relapsed or refractory multiple myeloma.

Methods

We did a single-centre, single-arm, phase 2 trial at the Affiliated Hospital of Xuzhou Medical University in China. Patients were eligible if they were aged 18–69 years, had histologically confirmed multiple myeloma, a Karnofsky Performance Score of 50 points or more, and met the International Myeloma Working Group diagnostic criteria for relapsed or refractory disease. Fludarabine (three daily doses of 30mg/m²) and cyclophosphamide (one daily dose of 750 mg/m²) were used to deplete lymphocytes before infusion of humanised anti-CD19 CAR T cells (1 × 10⁶ cells per kg) and murine anti-BCMA CAR T cells (1 × 10⁶ cells per kg). The primary outcome was the proportion of patients who achieved an overall response. Responses were assessed according to the International Myeloma Working Group criteria. This study is registered with the Chinese Clinical Trial Registration Center, number ChiCTR-OIC-17011272.

Findings

From May 1, 2017, to Jan 20, 2019, 22 patients were enrolled and 21 received an infusion of CAR T cells and were evaluable for safety and activity analyses. At a median follow-up of 179 days (IQR 72–295), 20 (95%) of 21 patients had an overall response, including nine (43%) stringent complete responses, three (14%) complete responses, five (24%) very good partial responses, and three (14%) partial responses. The most common adverse events included cytokine release syndrome (19 [90%] of 21), including 18 patients (86%) with grade 1–2 cytokine release syndrome. The most common serious adverse events were haematological toxicities, which occurred in 20 (95%) of 21 patients. Common grade 3 or higher adverse events included neutropenia (18 [86%]), anaemia (13 [62%]), and thrombocytopenia (13 [62%]). One patient died due to cerebral hemorrhage, which was considered related to sustained thrombocytopenia. No deaths were judged to be treatment-related.

Interpretation

Our results confirm that combined infusion of humanised anti-CD19 and anti-BCMA CAR T cells is feasible in patients with relapsed or refractory multiple myeloma, and the preliminary activity observed warrants further investigation in randomised trials. This dual CAR-T cell combinations might be a promising treatment option for relapsed or refractory multiple myeloma.

Funding

National Natural Science Foundation of China, Natural Science Foundation, Key Research and Development Plan of Jiangsu.