The impact of fitness and dose intensity on clinical outcomes with venetoclax-obinutuzumab in CLL.

Venetoclax-obinutuzumab (Ven-Obi) is a standard first-line therapy for chronic lymphocytic leukemia (CLL). The impact of age, fitness, and dose reductions remains unclear. We analyzed patients treated with Ven-Obi in the CLL13 and CLL14 trials, excluding patients with TP53 aberrations. Fitness was assessed using the cumulative illness rating scale (CIRS, >6) and creatinine clearance (≤70 mL/min). Among 410 patients (median age, 67 years), 55.7% were unfit (median age, 72 years) and 44.3% were fit (median age, 58 years). Overall response rate (ORR) was 89.5% in unfit and 96.1% in fit patients. Rates of undetectable minimal residual disease (uMRD) at <10-4 were 80.3% in unfit and 85.1% in fit patients. Progression-free survival (PFS) at 3 years was 86.4% vs 87.5% (hazard ratio, [HR], 1.12; 95% confidence interval [CI], 0.70-1.81; P = .63). Overall survival at 3 years was 91.8% vs 96.9% (HR, 2.02; 95% CI, 0.90-4.55; P = .088). Adverse events included neutropenia (62.7% unfit, 56.9% fit), infusion-related-reactions (44.3% unfit, 56.9% fit), fatigue (15.8% unfit, 35.9% fit), and infections (57.5% unfit, 69.6% fit). Venetoclax dose reductions of <80% occurred in 39.6% of unfit and 17.6% of fit patients, with lower ORR (83.3% vs 98.2%) and uMRD rates (74.2% vs 87.9%) in those with reduced dose intensities, but similar PFS. Dose reductions of <70% were associated with shorter PFS. Overall, this study shows comparable efficacy and toxicity of Ven-Obi in fit and unfit patients with CLL.