Pirtobrutinib Versus Ibrutinib in Treatment-Naïve and Relapsed/Refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma
Menés respectivement sur 662 et 282 patients atteints d'un lymphome à petits lymphocytes ou d'une leucémie lymphoïde chronique réfractaire ou récidivante, ces deux essais randomisés comparent l'efficacité, du point de vue du taux de réponse globale et de la survie sans progression, et la toxicité, d'une part du pirtobrutinib et de l'ibrutinib en traitement de première ligne, et d'autre part du pirtobrutinib et d'un traitement combinant bendamustine et rituximab
Purpose: Pirtobrutinib, a highly selective, noncovalent Bruton tyrosine kinase inhibitor (BTKi), has shown efficacy and safety in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) who received prior covalent BTKi. We report results, to our knowledge, from the first randomized head-to-head comparison of pirtobrutinib versus ibrutinib in BTKi-naïve CLL/SLL in both treatment-naïve (TN) patients and patients with relapsed/refractory (R/R) disease.
Patients and Methods: Patients (N = 662) were randomly assigned 1:1 to receive pirtobrutinib or ibrutinib. All patients were BTKi-naïve. Primary end points were overall response rate (ORR) by independent review committee (IRC) among all randomly assigned patients (intention to treat [ITT]) and in patients with R/R disease.
Results: The study met its primary end points, demonstrating statistically significant noninferiority (NI) of IRC-ORR for pirtobrutinib versus ibrutinib in both the ITT (87.0% [95% CI, 82.9 to 90.4] v 78.5% [95% CI, 73.7 to 82.9]; ORR ratio = 1.11 [95% CI, 1.03 to 1.19]; two-sided P < .0001) and R/R populations (n = 437; 84.0% [95% CI, 78.5 to 88.6] v 74.8% [95% CI, 68.5 to 80.4]; ORR ratio = 1.12 [95% CI, 1.02 to 1.24]; two-sided P < .0001). In TN patients (n = 225), IRC-ORR was 92.9% (95% CI, 86.4 to 96.9) with pirtobrutinib versus 85.8% (95% CI, 78.0 to 91.7) with ibrutinib. Investigator assessed ORR results were consistent. Investigator-assessed progression-free survival (PFS) favored pirtobrutinib in the ITT (hazard ratio [HR], 0.57 [95% CI, 0.39 to 0.83]), R/R (HR, 0.73 [95% CI, 0.47 to 1.13]), and TN (HR, 0.24 [95% CI, 0.10 to 0.59]) populations. Cardiac adverse event rates of atrial fibrillation/flutter and hypertension were lower with pirtobrutinib.
Conclusion: Pirtobrutinib demonstrated NI of ORR versus ibrutinib, with a favorable early PFS trend, particularly in TN patients, and a favorable safety profile including low rates of atrial fibrillation and hypertension
Journal of Clinical Oncology , article en libre accès, 2025