{"entity":{"id":"circle-pharma","kind":"company","name":"Circle Pharma","aka":[],"tldr":"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.","summary":"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.","asOf":"2026-09-04","links":[{"label":"AACR 2026 presentations","url":"https://circlepharma.com/circle-pharma-to-present-new-clinical-and-preclinical-data-at-aacr-2026"}],"tags":[],"related":[],"cancers":["sclc","tnbc","breast-hr-positive"],"sections":["targeted-therapy"],"technologies":[],"targets":["cdk4-6"],"drugs":[],"companies":[],"institutions":[],"pathways":["p53-cell-cycle"],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hq":"South San Francisco, CA","country":"US","companyType":"biotech","website":"https://circlepharma.com","investors":[],"funding":[]},"route":"/companies/circle-pharma/","neighbours":{"cancer":[{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"sclc","kind":"cancer","name":"Small-cell lung cancer","route":"/cancers/sclc/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"section":[{"id":"targeted-therapy","kind":"section","name":"Targeted Therapy","route":"/fronts/targeted-therapy/"}],"target":[{"id":"cdk4-6","kind":"target","name":"CDK4/6","route":"/targets/cdk4-6/"}],"pathway":[{"id":"p53-cell-cycle","kind":"pathway","name":"p53 / RB / cell-cycle checkpoint","route":"/pathways/p53-cell-cycle/"}],"idea":[{"id":"idea-bio1-macrocycle-ppi-campaign","kind":"idea","name":"Macrocyclic peptides to cover protein surfaces that pills cannot","route":"/ideas/idea-bio1-macrocycle-ppi-campaign/"}]}}