This is an open-label, multi-center, dose-escalation, Phase 1 study of PRT2527, a CDK9 inhibitor, evaluating participants with select R/R hematologic malignancies including aggressive B-cell lymphoma subtypes, mantle cell lymphoma (MCL), and chronic lymphocytic lymphoma (CLL)/small lymphocytic lymphoma (SLL), including Richter’s syndrome. The study will be conducted in two parts, the dose escalation phase and the dose confirmation phase. The dose escalation phase will evaluate escalating doses of PRT2527 until MTD is identified or when the RP2D is determined. The dose confirmation phase will evaluate indication-specific cohorts at the RP2D to confirm the dose. Approximately 51 participants will be enrolled in the dose escalation and indication-specific, dose confirmation cohorts.

This is a multicenter, open-label, dose-escalation, Phase 1 study of PRT1419, a MCL-1 inhibitor, evaluating participants with acute myeloid leukemia (AML), chronic myelomonocytic leukemia (CMML), myelodysplastic syndrome (MDS), MDS/myeloproliferative neoplasm (MPN) overlap syndrome, chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), and B-cell non-hodgkin lymphoma (NHL) including marginal zone lymphoma, follicular lymphoma or mantle cell lymphoma. Participants in study will receive PRT1419 as monotherapy or in combination with either Azacitidine (AZA) or Venetoclax (VEN). The study includes multiple dose escalations and expansion cohorts for RP2D confirmation.