Loxo@Lilly of Eli Lilly and Company announced that the U.S. Food and Drug Administration approved Jaypirca™ (pirtobrutinib, 100 mg & 50 mg tablets) for the treatment of adult patients with relapsed or refractory mantle cell lymphoma (MCL) after at least two lines of systemic therapy, including a Bruton's tyrosine kinase (BTK) inhibitor. Jaypirca was approved under the FDA's Accelerated Approval pathway based on response rate from the open-label, single-arm, international, Phase 1/2 study, called the BRUIN trial.1 Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial. Jaypirca, a highly selective kinase inhibitor, utilizes a novel binding mechanism and is the first and only FDA approved non-covalent (reversible) BTK inhibitor.

Jaypirca can reestablish BTK inhibition in MCL patients previously treated with a covalent BTK inhibitor (ibrutinib, acalabrutinib, or zanubrutinib) and extend the benefit of targeting the BTK pathway. The labeling for Jaypirca contains warnings and precautions for infections, hemorrhage, cytopenias, atrial fibrillation and flutter, second primary malignancies, and embryo-fetal toxicity. See Important Safety Information below and full Prescribing Information for additional information, including dosing modifications.

The FDA approval is based on data from a subset of patients in the BRUIN Phase 1/2 trial. The assessment of efficacy was based on 120 patients with MCL treated with Jaypirca 200 mg once daily until disease progression or unacceptable toxicity. Patients with active central nervous system lymphoma or allogeneic hematopoietic stem cell transplantation or CAR T-cell therapy within 60 days were excluded.

Patients had received a median of three prior lines of therapy (range: 1 to 9), with 93% having two or more prior lines; all patients received one or more prior lines of therapy containing a covalent BTK inhibitor. Eighty-three percent (83%) of patients discontinued their last BTK inhibitor due to refractory or progressive disease. Efficacy was based on overall response rate (ORR) and duration of response (DOR) as assessed by an independent review committee (IRC) using 2014 Lugano criteria.

The pooled safety analysis of the full BRUIN study population evaluated 583 patients with hematologic malignancies administered Jaypirca 200 mg daily as a single agent. In this pooled safety population, the most common adverse reactions (ARs) to Jaypirca therapy, occurring in 20% of patients or more, were decreased neutrophil count, decreased hemoglobin, decreased platelet count, fatigue, musculoskeletal pain, decreased lymphocyte count, bruising, and diarrhea. The safety of Jaypirca was evaluated in 128 patients with MCL, 36% of whom were exposed for six months or longer and 10% of whom were exposed for at least one year.

ARs led to dosage reductions in 4.7%, treatment interruption in 32%, and permanent discontinuation of Jaypirca in 9% of patients. ARs that resulted in permanent discontinuation of Jaypirca in more than 1% of patients included pneumonia. Serious ARs occurred in 38% of patients who received Jaypirca.

Serious ARs occurring in greater than or equal to 2% of patients were pneumonia (14%), COVID-19 (4.7%), musculoskeletal pain (3.9%), hemorrhage (2.3%), pleural effusion (2.3%), and sepsis (2.3%). Jaypirca is expected to be available in the United States in the coming weeks. The confirmatory Phase 3 trial (NCT04662255; BRUIN MCL-321) is currently enrolling patients.

The BRUIN Phase 1/2 clinical trial is the ongoing first-in-human, global, multi-center evaluation of Jaypirca in patients with hematologic malignancies, including mantle cell lymphoma (MCL). The trial includes a Phase 1 dose-escalation phase, a Phase 1b combination arm, and a Phase 2 dose-expansion phase. The primary endpoint of the Phase 1 study is maximum tolerated dose (MTD)/recommended Phase 2 dose (RP2D).

Secondary endpoints include safety, pharmacokinetics (PK), and preliminary efficacy measured by overall response rate (ORR) for monotherapy. The primary endpoint of the Phase 1b study is safety of the drug combinations. The secondary endpoints are PK and preliminary efficacy measured by ORR for the drug combinations.

The primary endpoint for the Phase 2 study is ORR as determined by an independent review committee (IRC). Secondary endpoints include ORR as determined by investigator, best overall response (BOR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), safety, and PK. Jaypirca (pirtobrutinib, formerly known as LOXO-305) (pronounced jay-pihr-kaa) is a highly selective (300 times more selective for BTK versus 98% of other kinases tested in preclinical studies), non-covalent (reversible) inhibitor of the enzyme BTK.2 BTK is a validated molecular target found across numerous B-cell leukemias and lymphomas including mantle cell lymphoma.3,4 Jaypirca is a U.S. FDA-approved oral prescription medicine, 100 mg or 50 mg tablets taken as a once-daily 200 mg dose with or without food until disease progression or unacceptable toxicity.