A Study of BI-1206 in Combination With Rituximab With or Without Acalabrutinib in Subjects With Indolent B-Cell NHL

This is a Phase 1/2a, multicenter, dose escalation, consecutive-cohort, open-label trial of BI-1206 in combination with rituximab with or without acalabrutinib in subjects with indolent relapsed or refractory B-cell NHL, sub-types FL (except FL grade 3B), MZL, and MCL. Phase 2a, consists of signal seeking cohorts followed by a randomized, parallel, two-arm dose optimization. The trial consists of 2 main parts: Phase 1 \- Dose Escalation, with two different Arms assessing IV or SC dosing of BI-1206 in combination with rituximab, with dose escalation cohorts and selection of the IV and SC doses of BI-1206 for Phase 2a Phase 2a * Dose Expansion, with one expansion cohort evaluating the selected IV dose of BI-1206 in combination with rituximab * Signal Seeking, assessing IV and SC dosing of BI-1206 in combination with rituximab and acalabrutinib. The Signal Seeking will consist of a Safety Run-in and an Expansion * Dose Optimization to select the recommended dose of BI-1206 in combination with rituximab and acalabrutinib