KEY TAKEAWAYS
- The study presented clinical safety data from the Phase I/II BRUIN trial focusing on pts who have been on pirtobrutinib for at least 12 months.
- Extended pirtobrutinib treatment showed a consistent and favorable safety profile, aligning well with earlier safety data from the broader study cohort.
Continuous treatment is essential for maintaining the therapeutic benefits of Bruton tyrosine kinase inhibitors (BTKis), making long-term safety and tolerability vital for patient compliance, dosage maintenance, and maximal effectiveness.
Pirtobrutinib, a reversible and highly selective BTKi, received FDA clearance in January 2023 to treat relapsed/refractory mantle cell lymphoma following two earlier lines of therapy that included a BTKi. It has shown notable effectiveness along with low rates of treatment discontinuation and dosage reduction across various relapsed/refractory B-cell malignancies.
This study measured key metrics like time to onset of adverse events, treatment discontinuation rates, and dose adjustments, particularly for treatment-emergent adverse events (TEAEs) observed in 20% or more patients (pts).
As of the data cutoff on July 29, 2022, the study enrolled 773 pts, of whom 326 (42%) had been treated for 12 months or more. The median duration of treatment for this subgroup was 19 months, with an interquartile range between 16 and 25 months. A significant majority, 231 (71%), continued to receive pirtobrutinib.
The most frequent treatment-emergent adverse events (TEAEs) among these long-term participants were fatigue (32%), diarrhea (31%), COVID-19 (29%), contusion (26%), cough (25%), and back pain (21%). Only 23 (7%) had dosage reductions due to TEAEs, while 11 (3%) discontinued treatment for the same reason. A total of four (1%) pts stopped the therapy because of a treatment-related adverse event (TRAE), and there was one fatal case attributed to TRAE (COVID-19 pneumonia).
The extended use of pirtobrutinib maintained a favorable safety profile suitable for long-term dosing, with no new or escalating safety concerns. The safety metrics for pts treated for at least 12 months aligned well with previous safety data from the general study population.
Source: https://clml-soho2023.elsevierdigitaledition.com/520/index.html
Clinical Trial: https://www.clinicaltrials.gov/study/NCT03740529
Muehlenbein, C.E., Coombs, C.C., Shah, N.N., Jurczak, W., Woyach, J., Cheah, C.Y., Patel, K., Maddocks, K., Wang, Y., Wang, C., Abhyankar, S., Tsai, D.E., Eyre, T.A. Long‑Term Safety With ≥12 Months of Pirtobrutinib in Relapsed/Refractory B‑Cell Malignancies.
