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Circle Pharma
Circle Pharma is developing CID-078, the first oral cyclin A/B RxL inhibitor, aimed at cancers with a broken G1/S checkpoint such as small-cell lung and triple-negative breast cancer.
CID-078 is an orally bioavailable macrocyclic peptide that blocks RxL-motif interactions of cyclins A and B, selectively killing E2F-high, RB1-altered tumour cells. Phase 1 (NCT06577987) began in October 2024 in advanced solid tumours including SCLC, TNBC, and ER+ breast cancer after CDK4/6 inhibitors; preclinical work published in Nature; clinical and preclinical updates at AACR 2026.