Pirtobrutinib and Mosunetuzumab for the Treatment of Relapsed/Refractory Grades 1-3A Follicular Lymphoma, PROMOTE-FL Trial

OUTLINE: Patients receive pirtobrutinib orally (PO) once daily (QD) on 7 days prior to the start of mosunetuzumab (day -7) and continue it until up to 52 weeks. Patients receive mosunetuzumab subcutaneously (SC) or intravenously (IV) on days 1, 8, and 15 of cycle 1 then on day 1 of remaining cycles. Cycles of mosunetuzumab repeat every 21 days for up to 17 cycles in the absence of disease progression or unacceptable toxicity. Patients with a CR after cycle 8 discontinue mosunetuzumab. Patients also undergo blood sample and oral swab and/or rectal swab collection, tissue biopsy (optional), computed tomography (CT), and positron emission tomography (PET)/CT throughout the study. Additionally, patients may undergo bone marrow aspiration and biopsy at screening and after cycle 8. After completion of study treatment, patients are followed up at 30 days then at standard of care intervals for up to 4 years.