FDA expands pirtobrutinib use to second-line CLL after covalent BTKi failure, broadening treatment options

The BRUIN CLL-321 phase 3 trial provided the data that led the FDA to approve pirtobrutinib for patients whose chronic lymphocytic leukemia has progressed after a covalent BTK inhibitor. This marks the first approval that does not require prior exposure to a BCL‑2 inhibitor.

The study enrolled individuals who had previously received a covalent BTKi, reflecting a typical real‑world population. Participants were randomly assigned to receive pirtobrutinib or the investigator's choice of therapy, allowing a direct comparison of outcomes.

Clinicians can now consider pirtobrutinib as a second‑line option without mandating a BCL‑2 inhibitor beforehand, giving patients more flexibility in treatment sequencing. The trial also highlighted the importance of comprehensive relapse workup, including PET‑CT, biopsy for suspected Richter transformation, and resistance or TP53 testing to guide therapy decisions.