A Study of PRT2527 in Participants With Relapsed/Refractory Hematologic Malignancies

This is a Phase 1 dose-escalation study of PRT2527, a potent and highly selective cyclin-dependent kinase (CDK) 9 inhibitor, in participants with select relapsed or refractory (R/R) hematologic malignancies. The purpose of this study is to evaluate the safety, tolerability, recommended phase 2 dose (PR2D), and preliminary efficacy of PRT2527.

Inclusion Criteria:Willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study proceduresHistologically or cytologically confirmed diagnosis of aggressive B-cell lymphoma subtypes, MCL or CLL/SLL, including Richter's syndrome, based on local testing that have relapsed or become refractory to or be ineligible for standard-of-care therapyMust provide either an archival or fresh tumor tissue sample from a core or excisional/surgical biopsyEastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1Adequate organ function (hematology, renal, and hepatic)Echocardiogram (or multigated acquisition [MUGA] scan) indicating a left ventricular ejection fraction of ≥ 50%Exclusion Criteria:Have active central nervous system involvement by malignancy, uncontrolled intercurrent illnesses, and active infections requiring systemic therapyHave undergone HSCT within the last 90 days or have graft versus host disease (GvHD) Grade > 1 at study entryMean corrected QT interval of > 470 msec following triplicate ECG measurements or a history of long QT SyndromeHave severe pulmonary disease with hypoxemiaHistory of another malignancy except for adequately treated non-melanoma skin cancer or lentigo maligna, superficial bladder cancer, and carcinoma in situ of the cervix without evidence of disease, and asymptomatic prostate cancer without known metastatic disease and no requirement for therapyConcurrent treatment with strong CYP3A4 inhibitors or inducersPrior exposure to a CDK9 inhibitorWait at least 5 half-lives of the agent or 14 days after their investigational or approved therapies before start of study treatment, whichever is shorter