A phase 1 single-arm, open-label study of emavusertib (CA-4948) in combination with azacitidine and venetoclax in patients (pts) with acute myeloid leukemia (AML) in complete response (CR) with measurable residual disease (MRD).

TPS6587 Background: Emavusertib is a novel potent oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4) with additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4). Inhibition of these 3 onco-proteins by emavusertib may address the unmet need for novel therapies in AML. Clinical studies with emavusertib monotherapy have demonstrated a significant reduction in AML blasts with clinical and molecular responses in pts with relapsed or refractory AML (Metzeler 2022). Azacitidine + venetoclax (aza+ven) is an approved therapy for newly diagnosed pts with AML, unfit for intensive chemotherapy. Pre-clinical studies have demonstrated that emavusertib in combination with aza+ven has synergistic and antileukemic effects. In the VIALE-A study, composite CR (CRc) (CR, CRh, or CRi) in the absence of MRD of <1 residual blast/1000 leukocytes (MRD negative MRD−) resulted in longer duration of response (DOR), event-free survival, and overall survival (OS) compared with AML pts who achieved CRc but were MRD+ (Pratz, 2022). Therefore, adding emavusertib to aza+ven in CR or CRh, MRD+ pts may convert MRD status without significant toxicity and become a potential new regimen in front-line therapy. Methods: This is a single-arm, open-label Phase 1 study of emavusertib in combination with first line aza+ven in AML pts ≥60 years of age who achieved CR or CRh with MRD+ status based on local testing. The primary objective is to determine a safe and tolerable dosing schedule for the triple combination. Secondary objectives include determining the MRD conversion rate, pharmacokinetics, DOR, and OS. The study will enroll approximately 24 pts at 5 to 10 sites globally. Pts will have received aza+ven as first line therapy and achieved CR or CRh after 1-6 cycles of aza+ven. If MRD status remains positive, emavusertib will be added to the existing aza+ven regimen. Key exclusion criteria include residual toxicities and significant comorbidities. In the first cohort, the starting emavusertib dose is 200 mg BID for 7 days per cycle of 28 days. The duration of emavusertib treatment will extend to 14 and 21 days, in subsequent cohorts. The pts will continue triple treatment (emavusertib+aza+ven) until consent withdrawal, disease progression, intolerable toxicity, or not achieving MRD- after 6 cycles of treatment. Enrollment to cohort 1 began in December 2023. (EU CT Number 2023-505828-58). Clinical trial information: 2023-505828-58.