A Promising Approach for Difficult-to-Treat Cancers
SY-5609 is a highly selective and potent oral inhibitor of the cyclin-dependent kinase 7 (CDK7) in a Phase 1 dose-escalation trial in patients with advanced breast, colorectal, lung, ovarian or pancreatic cancer, or with solid tumors of any histology that harbor Rb pathway alterations.
SY-5609 represents a new approach to treating cancer that we believe has potential in a range of difficult-to-treat cancers. It has shown robust anti-tumor activity, including complete regressions, in preclinical models of breast, colorectal, lung and ovarian cancers at doses below the maximum tolerated dose. In preclinical studies of breast, lung and ovarian cancers, deeper and more sustained responses were associated with the presence of Rb pathway alterations. SY-5609 has also shown substantial anti-tumor activity in combination with fulvestrant in treatment-resistant models of estrogen receptor-positive breast cancer, including those resistant to both fulvestrant and a CDK4/6 inhibitor. Early dose-escalation data demonstrated proof-of-mechanism at tolerable doses.