Infectious complications among CD19 CAR-T cell therapy recipients: A single-center experience

BACKGROUND

CD19 chimeric antigen receptor (CAR)-T cell therapy has emerged as an effective treatment in those with refractory or relapsed lymphoma. CD19 CAR-T cell therapy can cause direct and indirect toxic adverse effects and increased risk for infection. Infectious complications and optimal antimicrobial prophylaxis strategies are an ongoing area of investigation.

METHODS

A single-center retrospective cohort study was conducted to review recipients of CD19 CAR-T cell therapy between April 2018 and December 2020. Patient characteristics and clinical outcomes were extracted from the electronic health records.

RESULTS

Infectious complications were identified in 18/50 (36%) recipients with 31 episodes of infection. The median time to infection was 225 days (range 0-614). Bacterial infections were most common with bloodstream infection followed by sinusitis and skin and soft tissue infection. Eight viral infections were identified, most being respiratory viral illnesses. Two fungal infections were identified: Pneumocystis jirovecii pneumonia (PJP) and disseminated fusariosis. Seventeen infections (54.8%) were classified as severe: leading to death, requiring hospitalization, need for empiric intravenous antibiotics, or significant alteration in hospital course. No characteristics were found to be statistically significant risks for infection, although a trend toward significance was seen in prior autologous stem cell transplant recipients (p = .12) and those with recurrent neutropenia (p = .14). Three patients (6%) died from infection.

CONCLUSION

Infections were common after CD19 CAR-T cell therapy and occurred beyond the first year. Further multicenter studies are needed to define infectious risks and optimize antimicrobial prophylaxis recommendations in recipients of CD19 CAR-T cell therapy.

A comprehensive analysis of the fatal toxic effects associated with CD19 CAR-T cell therapy

To determine the incidence, spectrum, timing, and clinical features of CD19 Chimeric antigen receptor (CAR-T) cell therapy-associated fatal toxic effects. We initiated a comprehensive analysis. First, we retrospectively queried the real-world data from a World Health Organization (WHO) pharmacovigilance database (Vigilyze). Furthermore, we performed a meta-analysis of published trials of CD19 CAR-T cell therapy. From screening the WHO database, we identified 1200 patients: 499 received Kymriah therapy, and 701 received Yescarta therapy. We compared the adverse reactions of the two drugs. We evaluated all published clinical trials, comprising 19 trials and 890 patients. Our meta-analysis showed that the incidence of fatal toxic effects associated with death was 5.4%. Infections and infestations appeared to present the highest risk of death. The toxic effect specific median time to death was 30, 30, and 68 days for total, cytokine release syndrome (CRS), and nervous system disorders (NSD), respectively. We observed a high mortality rate for some toxic effects and an early onset of death with varied causes, indicating the need for clinicians to pay more attention to the monitoring and treatment of these fatal toxic effects when using CD19 CAR-T cell therapy, especially for infections and infestations.

Chimeric antigen receptor T cell therapy can be administered safely under the real-time monitoring of Th1/Th2 cytokine pattern using the cytometric bead array technology for relapsed and refractory acute lymphoblastic leukemia in children

CD19 chimeric antigen receptor T (CD19CAR-T) cell therapy has shown striking response in treating relapsed and refractory B-lineage acute lymphoblastic leukemia (r/r B-ALL). However, side-effects including cytokine release syndrome (CRS) and neurotoxicity can be fatal to patients. In this report, five patients with r/r B-ALL were treated with CD19CAR-T cells. Cytokine release syndrome experienced by four patients who achieved complete remission (CR) with minimal residual disease (MRD) negative. One patient who did not response to the treatment had no CRS. Acute toxicities including fever, hypotension and other neurological toxicities occurred in responding patients within 2 weeks post infusion and managed properly with tocilizumab and/or steroids according to the "real-time" monitoring of a simple 6 Th1/Th2 cytokine pattern. In conclusion, our study demonstrates that CD19CAR-T cell therapy can be safely administered for patients with relapsed and refractory leukemia under the "real-time" monitoring of a simple 6-cytokine pattern.

Treatment of Testicular Relapse of B-cell Acute Lymphoblastic Leukemia With CD19-specific Chimeric Antigen Receptor T Cells

BACKGROUND

Irradiation has been a standard treatment for testicular relapse but is associated with severe hypogonadism. Because CD19-specific chimeric antigen receptor T (CAR-T) cells can eradicate leukemic blasts in cerebrospinal fluid, a pharmacologic sanctuary site, we tested the efficacy of this therapy in 7 boys with isolated testicular relapse of B-cell acute lymphoblastic leukemia.

PATIENTS AND METHODS

CD19-specific CAR-T cells were generated with the use of autologous T cells transduced with a lentiviral vector to express a CAR molecule containing anti-CD19 scFv derived from the HI19α murine monoclonal antibody, human CD8α hinge, and human 4-1BB (CD137) and CD3ζ costimulatory signaling transmembrane domains. After the conditioning regimen, which consisted of intravenous fludarabine and intravenous cyclophosphamide, 7 patients with a median age of 9 years (range, 2-10 years) with isolated testicular relapse received a single infusion of CD19 CAR-T cells at a total dose of 5 × 10⁶ all T cells per kilogram.

RESULTS

All 7 patients achieved complete remission with normal testes. Six patients remained in second remission for 5 to 23 months (median, 14 months), and 1 patient subsequently relapsed in the bone marrow. The probability of event-free survival for all patients at 12 months of follow-up was 83.3% ± 15.2% (standard error). The treatment was well-tolerated, with grade 1 cytokine-release syndrome developing in 5 patients.

CONCLUSION

These results suggest that CAR-T cell therapy is a treatment option for patients with testicular relapse.