Pembrolizumab and Combination Chemotherapy in Treating Patients With Previously Untreated Diffuse Large B-cell Lymphoma or Grade 3b Follicular Lymphoma

This pilot phase I trial studies the side effects of pembrolizumab and combination chemotherapy in treating patients with previously untreated diffuse large B-cell lymphoma or grade 3b follicular lymphoma. Monoclonal antibodies, such as pembrolizumab and rituximab, may interfere with the ability of cancer cells to grow and spread. Drugs used in chemotherapy, such as cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone, work in different ways to stop the growth of cancer cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving pembrolizumab together with combination chemotherapy may be with a better treatment for diffuse large B-cell lymphoma or follicular lymphoma.