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Mantle Cell LymphomaAugust 2023

What the BRUIN Trial Found — Pirtobrutinib After Other BTK Inhibitors for Mantle Cell Lymphoma

BRUIN tested pirtobrutinib, a different kind of BTK inhibitor pill, in mantle cell lymphoma patients whose cancer had already come back after the standard BTK drugs (ibrutinib, acalabrutinib, or zanubrutinib). Across 166 patients, more than half saw their tumors shrink, and responses lasted nearly two years on average.

What the trial was testing

The BRUIN enrolled 166 patients with mantle cell lymphoma. The study was sponsored by Loxo Oncology and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was an early-stage trial — researchers are still confirming safety and getting an early look at how well the treatment works. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

58% of patients responded after their previous BTK inhibitor stopped working.

Journal of Clinical Oncology · 2023 · NCT03740529

These findings — that saw their mantle cell lymphoma respond to pirtobrutinib after other BTK inhibitors stopped working — were published in the Journal of Clinical Oncology and represent the headline result of the study.

Researchers tracked outcomes across 166 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with mantle cell lymphoma, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Pirtobrutinib (Jaypirca) received FDA accelerated approval in January 2023 for relapsed or refractory mantle cell lymphoma after at least two prior therapies, including a BTK inhibitor. It's a daily pill taken at home — a meaningful option when standard BTK drugs stop working, and when CAR-T therapy isn't right for you. Ask your oncologist whether you qualify.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.