A Phase 2 Open-Label, Multicenter, Dose Optimization Clinical Study of the Safety, Tolerability, and Pharmacokinetic (PK) and Pharmacodynamic (PD) Profiles of Cfi-400945 As a Single Agent or in Combination with Azacitidine or Decitabine in Patients with Acute Myeloid Leukemia

• Published in: Blood 2020-11, Vol.136 (Supplement 1), p.24-25
• Main Authors: Jonas, Brian A, Bixby, Dale L., Brandwein, Joseph M, Yee, Karen W.L., Murphy, Tracy, Minden, Mark D., Michelson, Glenn C., Bray, Mark R, Roberts-Thomson, Emily Elizabeth, Borthakur, Gautam
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2020-136004

Background: CFI-400945 is a potent, selective, orally administered, first-in-class inhibitor of the serine/threonine kinase, Polo-like kinase 4 (PLK4). PLK4 is a highly conserved master regulator of centriole duplication, and is critical for maintenance of genomic integrity. Aberrant expression of PLK4 results in a number of effects including the centrosome amplification often seen in aneuploid cancers, pointing to a potentially causative role for PLK4 in genome instability and cancer progression. A Phase 1 study has been completed evaluating CFI-400945 as a monotherapy in solid tumors, showing a tolerable safety profile and promising signs of activity. As acute myeloid leukemia (AML) is a disease characterized by genomic instability, it is of significant interest as a potential indication for the clinical evaluation of CFI-400945. pre-clinical studies, CFI-400945 showed potent activity towards leukemia cell lines and primary human samples in vitro, as well as marked efficacy in two subcutaneous models of leukemia, specifically the MV4-11 FLT3-ITD AML. A Phase 1 trial in AML was initiated at the Princess Margaret Cancer Center in 2018, and of six patients evaluable for response, two (33%) achieved complete remission (CR), and 3 patients (50%) had stable disease (with one patient having a 78% reduction in marrow blast count) [re: Murphy et al, ASH 2020]. These promising results have led to a plan for an expanded trial examining CFI-400945 in AML, particularly focused on complex karyotype (CK). Study Design and Methods: The study will have 4 parts, Part 1A (1A): a single agent dose escalation portion, Part 1B (1B): a food effect portion once the MTD of 1A is determined, and combinations with azacitidine (2A), and decitabine (2B). For parts 1A and 1B, patients with relapsed and/or refractory AML, MDS, or CMML after >1 prior therapy will be included. Patients with MDS or CMML must have progressed or had a lack of response after at least 4 cycles of hypomethylating agents. For parts 2A and 2B, patients should have relapsed and/or refractory AML or untreated MDS or CMML. Untreated patients who decline or are ineligible for intensive therapy may be included. The study will use a standard 3 + 3 design. The maximum tolerated dose (MTD) will be defined as the dose level where the number of dose limiting toxicities (DLTs) is