Pirtobrutinib is the first and only noncovalent Bruton’s tyrosine kinase inhibitor approved for use in this MCL setting, manufacturer Eli Lilly noted in a press release.
“The approval of Jaypirca represents an important advance for patients with relapsed or refractory MCL, who currently have limited options and historically have had a poor prognosis following discontinuation of treatment with a covalent Bruton’s tyrosine kinase inhibitor,” senior author Michael Wang, MD, University of Texas MD Anderson Cancer Center, Houston, said in the release.
The approval was based on efficacy demonstrated in the open-label, single-arm, phase 1/2 BRUIN trial – a multicenter study assessing 200 mg once-daily oral pirtobrutinib monotherapy in 120 patients with MCL who had previously received a Bruton’s tyrosine kinase inhibitor, most often ibrutinib (Imbruvica, 67%) acalabrutinib (Calquence, 30%) and zanubrutinib (Brukinsa, 8%). Pirtobrutinib was continued until disease progression or unacceptable toxicity.
Study participants had a median of three prior lines of therapy, and 83% discontinued their last Bruton’s tyrosine kinase inhibitor because of refractory or progressive disease.
The overall response rate in pirtobrutinib-treated patients was 50% with a complete response rate of 13%. Estimated median duration of response was 8.3 months, and the estimated duration of response at 6 months occurred in nearly two-thirds of patients.
Adverse reactions that occurred in at least 15% of patients included fatigue, musculoskeletal pain, diarrhea, edema, dyspnea, pneumonia, and bruising. Grade 3 or 4 laboratory abnormalities occurring in at least 10% of patients included decreased neutrophil counts, lymphocyte counts, and platelet counts.
Prescribing information for pirtobrutinib includes warnings and precautions for infections, hemorrhage, cytopenias, atrial fibrillation and flutter, and second primary malignancies, noted the FDA, which granted priority review, fast track designation, and orphan drug designation for the application submitted by Eli Lilly.
“Jaypirca can reestablish Bruton’s tyrosine kinase inhibition in MCL patients previously treated with a covalent Bruton’s tyrosine kinase inhibitor (ibrutinib, acalabrutinib, or zanubrutinib) and extend the benefit of targeting the Bruton’s tyrosine kinase pathway,” according to Eli Lilly’s release.
Dr. Wang added that the agent “has the potential to meaningfully impact the treatment paradigm for relapsed and refractory MCL patients.”
Meghan Gutierrez, CEO at the Lymphoma Research Foundation, also noted that “the approval of Jaypirca brings a new treatment option and, along with that, new hope for people with relapsed or refractory MCL.”
The drug is expected to be available in the United States in the coming weeks, and the confirmatory phase 3 BRUIN trial is currently enrolling patients, Eli Lilly announced. The company also indicated the list price would be $21,000 for a 30-day supply of the 200-mg dose.
Serious adverse events believed to be associated with the use of pirtobrutinib or any medicine or device should be reported to the FDA’s MedWatch Reporting System or by calling 1-800-FDA-1088.
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