Pirtobrutinib in Combination With Rituximab in Adults With Untreated Marginal Zone Lymphoma (PIONEER-MZL)

This study is testing a combination of two drugs — pirtobrutinib (a targeted cancer drug that blocks a protein called BTK) and rituximab (an antibody that targets cancer cells) — as a first treatment for a type of blood cancer called marginal zone lymphoma (MZL). **You may be eligible if...** - You are 18 or older - You have been diagnosed with marginal zone lymphoma (any subtype) confirmed by a biopsy - You have not had any systemic (whole-body) treatment for MZL before - Your blood counts, liver, and kidney function are within acceptable ranges **You may NOT be eligible if...** - You have had prior systemic drug treatment for MZL (prior antibiotics for certain infections or antiviral therapy is acceptable) - You have active cancer spreading to the brain or spinal fluid - You are pregnant or breastfeeding - You have a serious autoimmune condition requiring immune-suppressing medications Talk to your doctor to see if this trial is right for you.