Circle Pharma raises $93 million to push cancer drug toward the clinic
What's the deal? Circle Pharma, a South San Francisco clinical-stage biopharmaceutical company, has raised $92.5 million in an oversubscribed Series E round. The Column GroupDealroom has a profile for this one. Try Dealroom → led the financing, with participation from Nextech InvestDealroom has a profile for this one. Try Dealroom →, RA Capital Management, Euclidean CapitalDealroom has a profile for this one. Try Dealroom →, and a strategic investment from Eli Lilly and CompanyDealroom has a profile for this one. Try Dealroom →.
What's the endgame? Proceeds will advance CID-165, a first-in-class oral macrocyclic cyclin D1 RxL inhibitor, through early clinical development for ER-positive breast cancer. The drug is expected to enter clinical trials in the first quarter of 2027.
Why now? Cyclin D1 is a well-established driver of cancer, especially in ER-positive breast cancer, but directly targeting it has long been a challenge. CID-165 is designed to selectively disrupt the interaction between cyclin D1 and retinoblastoma protein, offering a novel way to hit that driver.
The company reports the drug has shown robust anti-tumor activity in preclinical models, both alone and in combination with CDK4/6-dual inhibitors, CDK4-selective inhibitors, and endocrine therapies.
What they're saying: "We believe CID-165 has the potential to become a new backbone therapy for ER-positive breast cancer and this financing provides us with the resources to generate meaningful clinical data to validate that potential," said David J. Earp, president and chief executive officer.
The funding also supports Circle Pharma's broader pipeline of cyclin-targeted macrocycles, which the company frames as first-in-class compounds against a previously undrugged family of proteins that regulate the cell cycle.
The signal: The round sits in the upper range for its category, and Eli LillyDealroom has a profile for this one. Try Dealroom →'s strategic backing signals large-pharma interest in Circle Pharma's macrocycle platform. It underscores continued investor appetite for oncology startups pursuing targets long considered undruggable.
Image credit: Circle Pharma
