AU4-53

AU4-53 is an orally bioavailable small molecule dual inhibitor of cyclin-dependent kinase 9 (CDK9) and tropomyosin receptor kinase (TRK), currently in late-stage preclinical development by Aucentra Therapeutics. It exhibits picomolar potency and high selectivity. The mechanism of action involves the inhibition of CDK9, which suppresses the transcription of key oncogenes such as MYC, MCL1, and BCL-2, thereby inducing apoptosis in cancer cells. Simultaneously, its inhibition of TRK kinases targets oncogenic signaling driven by NTRK gene fusions or mutations. This dual-targeting approach is designed to provide broad-spectrum anticancer activity and overcome resistance mechanisms associated with single-target TRK inhibitors. AU4-53 has demonstrated efficacy in various preclinical models, including hematological malignancies and solid tumors like breast, lung, and ovarian cancers, as well as NTRK-fusion-driven sarcomas.