The FDA has approved Eli Lilly's pirtobrutinib (Jaypirca) as a first-line treatment for adults with previously untreated chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) without a 17p deletion. Based on the phase 3 BRUIN CLL-313 trial, pirtobrutinib reduced the risk of disease progression or death by 80% compared to standard chemoimmunotherapy, achieving a 94% overall response rate. While the drug offers a highly effective targeted option early in therapy, clinicians must weigh its continuous-treatment model and safety warnings, including cytopenias and cardiac risks.
FDA approval and regulatory history
- ▪The FDA's expanded frontline indication for pirtobrutinib follows a December 2023 accelerated approval and a December 2025 traditional approval for adults with relapsed or refractory chronic lymphocytic leukemia or small lymphocytic lymphoma
- ▪The FDA approved Eli Lilly's pirtobrutinib on October 2, 2026, as a first-line treatment for adults with previously untreated chronic lymphocytic leukemia or small lymphocytic lymphoma without a known 17p deletion
Patient population and recommendations
- ▪Eli Lilly and Company estimated that approximately 92% to 95% of patients diagnosed with chronic lymphocytic leukemia do not have a 17p deletion
- ▪The National Comprehensive Cancer Network lists pirtobrutinib as a category 2A recommendation for treatment-naive adults with chronic lymphocytic leukemia or small lymphocytic lymphoma without a 17p deletion
BRUIN CLL-313 trial efficacy
- ▪In the BRUIN CLL-313 trial, 52.9% of patients with progressive disease on bendamustine plus rituximab crossed over to pirtobrutinib, which could complicate overall survival comparisons
- ▪In the phase 3 BRUIN CLL-313 trial, pirtobrutinib reduced the risk of disease progression or death by 80% compared to bendamustine plus rituximab (hazard ratio 0.20), with median progression-free survival not estimable versus 33.5 months
- ▪The overall response rate in the BRUIN CLL-313 trial was 94% with pirtobrutinib compared to 81% with bendamustine plus rituximab, though complete responses were higher with chemoimmunotherapy at 21% versus 13%
Trial design and limitations
- ▪The BRUIN CLL-313 trial excluded patients with significant cardiovascular disease, meaning the observed 1.4% rate of atrial fibrillation or flutter may not generalize to patients with cardiac comorbidities
- ▪The phase 3 BRUIN CLL-313 trial was an open-label study that evaluated 282 adults with previously untreated chronic lymphocytic leukemia or small lymphocytic lymphoma
Safety and adverse reactions
- ▪The prescribing information for pirtobrutinib includes warnings for infections, hemorrhage, cytopenias, cardiac arrhythmias, second primary malignancies, hepatotoxicity, and embryo-fetal toxicity
- ▪The most common nonlaboratory adverse reactions for pirtobrutinib in trials were upper respiratory tract infections at 27%, rash at 22%, and COVID-19 at 21%
- ▪Serious adverse reactions occurred in 28% of patients receiving pirtobrutinib, and the most common grade 3 or 4 laboratory abnormality was a decreased neutrophil count
Pirtobrutinib dosing and administration
- ▪Because pirtobrutinib is administered continuously until disease progression or unacceptable toxicity, the duration of treatment may factor into payer and formulary assessments
- ▪In the BRUIN CLL-313 trial, patients randomized to the pirtobrutinib arm received 200 mg of the drug orally once daily
Debatable claims
- ▪The BRUIN CLL-313 trial safety data fail to reflect real-world risks for typical CLL/SLL patients
- ▪Pirtobrutinib should replace chemoimmunotherapy as the standard first-line treatment for CLL/SLL
- ▪The continuous administration of pirtobrutinib does more harm than good
- ▪Progression-free survival is an insufficient metric for approving first-line leukemia treatments
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