Relapse following chemeric antigen receptor (CAR) T-cell therapy can arise from progressive loss of the CAR T cells or from loss of the target antigen by tumor cells. Wang et al report that using a mix of CAR T cells targeting CD19 and CD22 reduces relapse with antigen-negative tumor cells. However, a lack of CAR T-cell persistence leads to increased relapse with antigen-positive cells.

B cell maturation antigen- (BCMA) specific chimeric antigen receptor (CAR) T-cell therapies have shown efficacy in relapsed, refractory multiple myeloma (RRMM). Since the non-human originated antigen-targeting domain may limit clinical efficacy, we developed a fully human BCMA-specific CAR, CT103A, and report its safety and efficacy in a phase I trial. Eighteen consecutive RRMM patients, including four patients with prior murine BCMA CAR exposures, were enrolled. CT103A was administered at 1, 3, and 6 × 106 CAR-positive T cells/kg in the dose-escalation phase, and 1 × 106 CAR-positive T cells/kg in the expansion cohort. The overall response rate (ORR) was 100%, with 72.2% of the patients achieving complete response or stringent complete response (sCR). For the four murine BCMA CAR-exposed patients, three achieved sCR, and one achieved a very good partial response. At one year, the progression-free survival rate was 58.3% for all cohorts and 79.1% for the patients without extramedullary myeloma. Hematologic toxicities were the most common adverse events. 70.6% of the patients experienced grade 1 or 2 cytokine release syndromes. No immune effector cell-associated neurotoxicity syndrome was observed. To the cutoff date, CAR transgenes were detectable in 77.8% of the patients. The median CAR transgene persistence was 307.5 days. Only one patient was positive for the anti-drug antibody. Altogether, CT103A is safe and highly active in RRMM patients and can be developed as a promising therapy for RRMM. Patients who relapsed from prior murine BCMA CAR T-cell therapy may still benefit from CT103A. (Chinese Clinical Trial Registry ChiCTR1800018137)

BackgroundChimeric antigen receptor-modified (CAR) T-cell immunotherapy is a novel promising therapy for treatment of B-cell malignancy. Cytokine release syndrome (CRS) and infection are the most common adverse events during CAR T-cell therapy. Similar clinical presentation of concurrent CRS and infection makes it difficult to differentially diagnose and timely treat the condition.MethodsWe analyzed the features of infection events during the first 30 days after CAR T-cell infusion (CTI) in 109 patients from three clinical trials (ChiCTR-OPN-16008526, ChiCTR-OPC-16009113, ChiCTR-OPN-16009847). Based on the dynamic changes of interleukin (IL)-6 and ferritin, we proposed the “double peaks of IL-6” pattern as a feature of life-threatening infection during the first 30 days after CTI. Meanwhile, we screened candidate biomarkers from 70-biomarker panel to establish a prediction model for life-threatening infection.ResultsIn this study, 19 patients (17.4%) experienced a total of 19 infection events during the first 30 days after CAR T-cell infusion. Eleven patients (10.1%) had grade 4–5 infection, which were all bacterial infection and predominantly sepsis (N = 9). “Double peaks of IL-6” appeared in 9 out of 11 patients with life-threatening infection. The prediction model of three-cytokines (IL-8, IL-1β and interferon-γ) could predict life-threatening infection with high sensitivity (training: 100.0%; validation: 100.0%) and specificity (training: 97.6%; validation: 82.8%). On base of the aforementioned methods, we proposed a workflow for quick identification of life-threatening infection during CAR T-cell therapy.ConclusionsIn this study, we worked out two diagnostic methods for life-threatening infection during CAR T-cell therapy by analyzing inflammatory signatures, which contributed to reducing risks of infection-induced death.