Circle Pharma Closes $92.5 Million Series E to Take Oral Macrocyclic Cyclin D1 Inhibitor CID-165 Into the Clinic for ER-Positive Breast Cancer
Circle Pharma announced on Wednesday, September 16, 2026 an oversubscribed $92.5 million Series E financing led by The Column Group, with participation from Nextech Invest, RA Capital Management, Euclidean Capital, and Eli Lilly and Company. The South San Francisco company said the money will take CID-165, which it describes as a first-in-class oral macrocyclic cyclin D1 RxL inhibitor, through early clinical development in ER-positive breast cancer and support its broader pipeline of cyclin-targeted macrocycles. Circle expects CID-165 to enter clinical development in the first quarter of 2027.