Developing a Novel Anti-CD19/CD20 Bi-Specific Chimeric Antigen Receptor T (CAR-T) Cell Therapy for Relapsed/Refractory (r/r) B-Cell NHL

Background:

Aiming to improve both the response rate and durability of response while limiting antigen escape of CD-19 following anti-CD-19 CAR-T therapy, C-CAR039 has been developed as a 2nd generation 4-1BB novel bi-specific chimeric antigen receptor T (CAR-T) therapy targeting both CD19 and CD20 antigens.

Methods:

NCT04317885 is a single arm, single-center, non-randomized phase I clinical trial designed to evaluate the safety and efficacy of C-CAR039 in treatment of relapsed or refractory NHL (r/r NHL) patients. The primary objective of the study is to evaluate incidence and severity of treatment emergent adverse events. The secondary objectives include determining overall response rate (ORR), progression-free survival, and overall survival.

Results:

In preclinical studies, human T cells transduced with the lentiviral vector encoding C-CAR039in vitroshowed CAR-T proliferation, cytokine production, cytotoxicity to CD19, and CD20 single positive and double positive tumor cells. C-CAR039 can eradicate CD19/CD20 positive tumor cellsin vivobased on our animal model study.

A Phase 1 trial was conducted in Shanghai Tongji Hospital in patients with r/r NHL to assess the safety and efficacy of C-CAR039 (NCT04317885). Following apheresis to harvest T cells, C-CAR039 was manufactured and infused as a single intravenous dose after a standard 3-day cyclophosphamide/fludarabine conditioning regimen. C-CAR039 was manufactured in a serum free, semi-automated, and digitally closed system with median vein to vein time of 18 days. The manufacturing success rate was 100%. As of Aug 3, 2020, 16 patients were infused with C-CAR039 with a dose range of 1.0 x 10⁶ to 5.0 x 10⁶ CAR-T cells/kg. 14 patients had at least one-month evaluable safety data and 13 patients (11 DLBCL, 2 FL patients) had one-month or longer efficacy data. C-CAR039 treatment was well tolerated with no grade 3 or higher cytokine release syndrome(CRS) and no neurotoxicity event. Reversible grade 1~2 CRS was observed in 12 (86%) of patients. Cytopenias due to the conditioning regimen were common and reversible. At the one-month evaluation, 12/13 patients showed clinical improvement (ORR=92%) and 11/11 of DLBCL patients responded to the treatment (ORR=100%). Median follow-up was 70 days (range: 35-257 days). The best overall response (BOR) includes 10 complete responses (CRs) and 2 partial responses (PRs). Furthermore, C-CAR039 proliferation and expansion in the peripheral blood positively correlated with tumor regression.

Conclusion:

C-CAR039 shows promising efficacy and a favorable safety profile in the early clinical trial in patients with r/r NHL. The early clinical efficacy signal is encouraging and compares favorably to anti-CD19 CAR-T therapies. These findings need to be evaluated in more patients with longer follow-up to confirm safety, efficacy and duration of response.