This phase II / III trial tests whether it is possible to decrease the chance of high-grade B-cell lymphomas returning or getting worse by adding a new drug, venetoclax to the usual combination of drugs used for treatment. Venetoclax may stop the growth of cancer cells by blocking a protein called Bcl-2. Drugs used in usual chemotherapy, such as rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide, 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 venetoclax together with usual chemotherapy may work better than usual chemotherapy alone in treating patients with high-grade B-cell lymphomas, and may increase the chance of cancer going into remission and not returning. eligibility includes being at least 18 years old and:
•Pathologic diagnosis of diffuse large B-cell lymphoma (DLBCL) or high grade B-cell lymphoma (HGBCL).
•High grade B-cell lymphoma with translocations of MYC and BCL2 (double hit lymphoma, DHL), or DLBCL or high grade B-cell lymphoma not otherwise specified (NOS) with protein expression