Zamtocabtagene Autoleucel in Relapsed/refractory B-NHL: 5-year Follow Up of a CD20/19 tandem CAR T Cell Phase 1 Trial

Emerging long-term data indicates relapse rates of over 50% after CD19 redirected chimeric antigen receptor (CAR) T cell therapy in relapsed or refractory (r/r) B-cell non-Hodgkin lymphoma (B-NHL). To reduce selective pressure on the CD19 antigen we conducted a first-in-human phase I clinical trial of zamtocabtagene autoleucel (zamto-cel) - a non-cryopreserved tandem CD20-CD19-directed CAR-T cell therapy. Two predefined dose levels (DL1=1x106 and DL2=2.5x106 CAR+ T cells/kg body) were applied. The primary endpoint (EP) was the maximum tolerated dose (MTD). Secondary EPs included adverse events (AEs), best overall response (BOR) and biomarker assessments. A total of 12 patients, 6 per dose level were treated. No DLT and no cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS) grade ≥3 were observed. Thus, MTD was not reached. The BOR by investigator assessment was 75% with 5/12 patients (42%) achieving complete remission (CR) until month 12 with no relapse in clinical evaluation up to 5 years after infusion. CR was associated with higher mean Cmax and detection of zamto-cel beyond month 6. Additional product characterization revealed increased expression of CD27 and CD127 along with increased expansion of CAR+ TCM cells in patients with CR, thus facilitating persistence and improved outcomes in r/r B-NHL treated with zamto-cel. Based on the promising risk-to-benefit ratio, evaluation of zamto-cel at DL2 is ongoing in pivotal Phase II clinical trials for patients with r/r aggressive B-NHL. This trial was registered at www.clinicaltrials.gov as #NCT03870945.