Venetoclax-Obinutuzumab for previously untreated chronic lymphocytic leukemia: 6-year results of the phase 3 CLL14 study

• One year fixed-duration Ven-Obi produces durable treatment-free remissions, with a 6-year PFS rate of 53% and TTNT rate of 65%, in CLL

• End-of-treatment minimal residual disease status is associated with progression-free and overall survival

Venetoclax-obinutuzumab (Ven-Obi) is a standard-of-care for patients with previously untreated chronic lymphocytic leukemia (CLL). In the CLL14 study, patients with previously untreated CLL and coexisting conditions were randomized to 12 cycles of Ven-Obi (n=216) or chlorambucil-obinutuzumab (Clb-Obi, n=216). Progression-free survival (PFS) was the primary endpoint. Key secondary endpoints included time-to-next-treatment (TTNT), rates of undetectable minimal residual disease (uMRD), overall survival (OS) and rates of adverse events. Patient reported outcomes (PROs) of time until definitive deterioration (TUDD) in quality of life (QoL) were analyzed. At a median observation time of 76.4 months, PFS remained superior for Ven-Obi compared to Clb-Obi (median 76.2 vs 36.4 months; HR 0.40[95%CI 0.31-0.52], p<0.0001). Likewise, TTNT was longer after Ven-Obi (6-year-TTNT 65.2% vs 37.1%; HR 0.44, 95%CI 0.33-0.58, p<0.0001). In the Ven-Obi arm, presence of del(17p), unmutated-IGHV and lymph node size ≥5 cm were independent prognostic factors for shorter PFS. Five years after treatment, 17 patients (7.9% of intention-to-treat-population) in the Ven-Obi arm had uMRD (<10-4 in peripheral blood) compared to 4 (1.9%) in the Clb-Obi arm. 6-year-OS rate was 78.7% in the Ven-Obi and 69.2% in the Clb-Obi arm (HR 0.69[95%CI 0.48-1.01], p=0.052). A significantly longer TUDD in global health status/QoL was observed in the Ven-Obi compared to the Clb-Obi arm (median 82.1 vs 65.1 months; HR 0.70[95%CI 0.51-0.97]). Follow-up adjusted SPM incidence rates were 2.3 and 1.4/1000 patient-months in the Ven-Obi and Clb-Obi arm, respectively. The sustained long-term survival, uMRD and QoL benefits support the use of one-year fixed-duration Ven-Obi in CLL. NCT02242942, EudraCT 2014-001810-24-