RecruitingProcedureTesting the Safety of Anti-Cancer Drug, CX-5461 (Pidnarulex), in Treating Lymphoma With Specific Changes in the MYC GeneThis phase Ib/II trial tests the safety, side effects, best dose and how well giving CX-5461 works for the treatment of patients with B-cell non-Hodgkin lymphoma. CX-5461 may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Giving CX-5461 may be safe, tolerable and/or effective in treating patients with B-cell non-Hodgkin lymphoma.