High rate of durable responses with undetectable minimal residual disease with frontline venetoclax and rituximab in young and fit patients with chronic lymphocytic leukemia and an adverse biologic profile: results of the GIMEMA phase II LLC1518 - 'Veritas' study.

ABSTRACT

The GIMEMA phase II LLC1518 VERITAS trial investigated the efficacy and safety of frontline, fixed-duration venetoclax and rituximab (VenR) combination in young (≤65 years) and fit patients with chronic lymphocytic leukemia (CLL) and unmutated IGHV and/or TP53 disruption. Treatment consisted of the Ven ramp-up, six-monthly courses of the VenR combination, followed by six monthly courses of Ven single agent. A centralized assessment of measurable minimal residual disease (MRD) was performed on the peripheral blood (PB) and bone marrow (BM) by ASO-PCR at the end of treatment (EOT) and during the follow-up. The primary endpoint was the complete remission (CR) rate at the EOT. Seventy-five patients were enrolled; the median age was 54 years (range 38-65), 96% had unmutated IGHV, 9 (12%) had TP53 disruption, and 4% were IGHV mutated with TP53 disruption. The overall response rate (ORR) at the EOT was 94.7%, with a CR rate of 76%. An undetectable (u) MRD was recorded in 69.3% of patients in the PB and 58.7% in the BM. The 12-month MRD-free survival in the 52 patients with uMRD in the PB at the EOT was 73.1%. After a median follow-up of 20.8 months, no disease progressions were observed. Three patients have died, two due to Covid-19 and 1 to tumor lysis syndrome. The first report of the VERITAS study shows that frontline VenR was associated with a high rate of CRs and durable responses with uMRD in young patients with CLL and unfavorable genetic characteristics.