PURPOSE A combination of anti–B-cell maturation antigen (BCMA) and anti-CD19 chimeric antigen receptor (CAR) T cells induced high response rates in patients with relapsed or refractory (R/R) multiple myeloma (MM), but long-term outcomes have not been assessed yet. PATIENTS AND METHODS In this single-arm, phase II trial, patients with R/R MM received a combination of anti-BCMA CAR T cells and anti-CD19 CAR T cells at a dose of 1 × 106 cells/kg, after receiving a conditioning chemotherapy consisting of cyclophosphamide and fludarabine. The overall response, long-term outcomes, and safety were assessed, as were their associations with clinical and disease characteristics. RESULTS Of 69 enrolled patients, 62 received the combined infusion of anti-BCMA and anti-CD19 CAR T cells with a median follow-up of 21.3 months. The overall response rate was 92% (57/62), and complete response or better was observed in 37 patients (60%). Minimal residual disease–negativity was confirmed in 77% (43/56) of the patients with available minimal residual disease detection. The estimated median duration of response was 20.3 months (95% CI, 9.1 to 31.5). The median progression-free survival was 18.3 months (95% CI, 9.9 to 26.7), and the median overall survival was not reached. Patients with extramedullary disease had significantly inferior survival. Fifty-nine patients (95%) had cytokine release syndrome, with 10% grade 3 or higher. Neurotoxic events occurred in seven patients (11%), including 3% grade 3 or higher. Late adverse effects were rare, except for B-cell aplasia, hypogammaglobulinemia, and infections. CONCLUSION The combination of anti-BCMA and anti-CD19 CAR T cells induced durable response in patients with R/R MM, with a median progression-free survival of 18.3 months and a manageable long-term safety profile.

Systematic and dynamic humoral immune reconstitution is little known for relapse/refractory (R/R) multiple myeloma (MM) patients who received anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR)-T cell therapy. We investigated the kinetics of B cell, normal plasma cell and immunoglobulin recovery in 40 patients who achieved ongoing response after anti-BCMA CAR-T cell therapy. All patients developed B-cell aplasia and the median duration of B-cell aplasia was 70 days (23-270). B cell count reached nadir on a median of day 7 and returned to baseline level on a median of day 97. BCMA positive cells in bone marrow turned undetectable on a median time of day 28 (13-159) in 94.87% (37/39) patients. Normal plasma cells in bone marrow were first re-detectable on a median of day 212. All patients developed a significant decrease in serum IgG, IgA, and IgM on a median of day 60. Recovery of serum IgG, IgM and IgA was observed in 53.33% (8/15) patients (non- IgG MM), 73.08% (19/26) patients (non- IgM MM) and 23.81% (5/21) patients (non- IgA MM) at 1-year, respectively. Median times to IgG, IgM and IgA recovery were on day 386, 254 and not reached during follow-up, respectively. Virus-specific IgG levels decreased with loss of protection. Twenty-three of 40 (57.5%) patients developed a total of 44 infection events. No infection-related deaths. These results reveal a 7-month aplasia of bone marrow normal plasma cells and a longer hypogammaglobulinemia, suggesting a profound and lasting humoral immune deficiency after anti-BCMA CAR-T cell therapy, especially for IgA.

Few studies have described chimeric antigen receptor (CAR) T-cell therapy for B-cell acute lymphoblastic leukemia (B-ALL) patients with central nervous system leukemia (CNSL) due to concerns for poor response and treatment-related neurotoxicity. Our study included 48 relapsed/refractory B-ALL (R/R B-ALL) patients with CNSL to evaluate the efficacy and safety of CD19-specific CAR T-cell-based therapy. The infusion resulted in overall response rate of 87.5% (95% confidence interval [CI], 75.3-94.1) in bone marrow (BM) disease and remission rate of 85.4% (95% CI, 72.8-92.8) in CNSL. With a median follow-up of 11.5 months (range, 1.3-33.3), the median event-free survival (EFS) was 8.7 months (95% CI, 3.7-18.8), and the median overall survival (OS) was 16.0 months (95% CI, 13.5-20.1). The cumulative incidences of relapse (CIR) in BM and CNS diseases were 31.1% and 11.3%, respectively, at 12 months (p=0.040). The treatment was generally well tolerated with 9 patients (18.8%) experiencing grade ≥3 cytokine release syndrome. Grade 3-4 neurotoxic events (NEs), which developed in 11 patients (22.9%), were associated with a higher pre-infusion disease burden in CNS and were effectively controlled under intensive management. Our results suggested that CD19-specific CAR T-cell-based therapy could induce similar high response rate in both BM and CNS diseases. The duration of remission in CNSL was longer than that in BM disease. CD19 CAR T-cell therapy may provide a potential treatment option for those previously excluded CNSL patients with manageable neurotoxicity. Clinical trials were registered at www.clinicaltrials.gov as # NCT02782351 and www.chictr.org.cn as # ChiCTR-OPN-16008526.

Clinical trials have confirmed that chimeric antigen receptor (CAR) T cell therapies are revolutionizing approaches for treating several relapsed or refractory hematological tumors. Cytokine release syndrome (CRS) is an adverse event with high incidence during CAR-T treatment. A further understanding of the characteristics and related risk factors of CRS is important for effective management. A total of 142 patients with relapsed or refractory acute lymphocyte leukemia (ALL), lymphoma, or multiple myeloma (MM) received lymphodepletion chemotherapy followed by infusion of CAR-T cells. The characteristics of CRS at different time points after treatment were monitored and risk factors were analyzed. The incidence of CRS for ALL, lymphoma, and multiple myeloma were 82%, 90%, and 90% respectively. Fever was observed on a median of day 3 for ALL, day 1 for lymphoma, and day 8.5 for MM after CAR-T cell infusion, and the duration was different between grade 1–2 CRS and grade 3–5 CRS. Disease types, peak concentration of IL-6, and CRP were associated with CRS. For patients with ALL, numbers of lymphoblast in bone marrow before lymphodepletion, peak concentration of IL-6, and CRP were independent risk factors of CRS. Clinical stage of lymphoma patients and high tumor burden in marrow of MM patients were independent risk factors of CRS. In conclusion, the characteristics and risk factors of CRS in different B-cell hematological tumors are different and should be managed individually during CAR-T cell therapy.

Our study suggests that NLR not PLR can be acted as an independent prognostic factor for analyzing the clinical outcome of MM patients.