KTE-X19 Confers Clinical Benefit for Patients with R/R MCL and Prior BTKi Exposure

KTE-X19, an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, was associated with relatively high responses and survival rates over 12 months in patients with relapsed or refractory (R/R) mantle cell lymphoma (MCL) who had progressed following prior Bruton’s tyrosine kinase inhibitor (BTKi) exposure, according to results of the ZUMA-2 trial.

The study was presented by Michael Wang, MD, of the University of Texas MD Anderson Cancer Center, at the 62nd American Society of Hematology Annual Meeting & Exposition. The researchers explained in their session that patients with MCL who progress following BTKi therapy have a median overall survival of only 5.8 months with salvage therapies, emphasizing the need for more effective approaches for these patients.

In the study, Dr. Wang and colleagues enrolled patients with R/R MCL who had progressed in their disease following receipt of prior ibrutinib (76%), acalabrutinib (15%), or both (9%). Following leukapheresis and conditioning chemotherapy, patients received a single infusion of 2×106 KTE-X19 per kilogram of body weight.

Patients in the study presented with classical MCL (n=40), blastoid MCL (n=17), or pleomorphic MCL (n=4). The overall response rates (ORRs) were 93% in patients with classical MCL, 88% in those with blastoid MCL, and 100% in patients with pleomorphic MCL. The rates of complete response (CR) were 65% in those with classical MCL, 53% in patients with blastoid MCL, and 75% in patients with pleomorphic MCL.

In patients with prior ibrutinib treatment, the ORR rate with KTE-X19 was 94%, and the CR rate was 65%. Patients who previously received acalabrutinib had an ORR rate of 80% and a CR of 40% with KTE-X19. The ORR and CR rates were each 100% in patients who previously received both BTKis.

In addition, the 12-month survival rates in patients with classical, blastoid, or pleomorphic MCL were 86.7%, 67.9%, or 100.0%, respectively. Stratified by prior therapy, the 12-month survival rates were 81% with prior ibrutinib, 80% with prior acalabrutinib, and 100% with both.

Approximately 15% of patients with classical MCL experienced grade ≥3 cytokine release syndrome (CRS), whereas 38% of patients with classical MCL experienced neurologic events. Grade ≥3 CRS was reported in 6% of patients with blastoid MCL and 25% of patients with pleomorphic MCL. Additionally, neurologic events were reported in 8% and 50% of patients with blastoid and pleomorphic MCL, respectively.