This clinical trial is for men and women with a diagnosis of chronic lymphocytic leukemia (CLL) and Richter’s transformation. Richter’s transformation occurs when CLL changes into a type of diffuse large B cell lymphoma (DLBCL).
   
The purpose of this study is to evaluate the safety and efficacy of the investigational drug, Polatuzumab vedotinin, in combination with a standard chemoimmunotherapy regimen.

An investigational drug means it has not been approved by the United States Food and Drug Administration (FDA). Polatuzumab vedotin is currently FDA approved in combination with bendamustine and rituximab for the treatment of adult patients with relapsed or refractory diffuse large B cell lymphoma (DLBCL) after at least two prior therapies, but not for Richter’s transformation.
   
Participants will be admitted to the hospital for close monitoring while the study drug is being administered along with the standard chemotherapy. Participants will receive the study drug over the course of Days 1 through 5 and are required to take some concomitant medications to help prevent infection and diminish side effects.
   
Participants will be treated on this study for approximately 5 months with a follow-up period lasting about 6 months after treatment with the investigational drug concludes.