{"entity":{"id":"lerociclib","kind":"drug","name":"Lerociclib","aka":["G1T38"],"tldr":"Lerociclib is a CDK4/6 inhibitor from G1 Therapeutics developed in China by Genor Biopharma, in a phase 3 trial with letrozole for hormone receptor-positive breast cancer.","summary":"G1 Therapeutics designed lerociclib (G1T38) as a CDK4/6 inhibitor that could be taken continuously without a break; it licensed Chinese rights to Genor Biopharma, which runs the phase 3 LEONARDA trials with letrozole or fulvestrant in HR-positive, HER2-negative advanced breast cancer. EQRx briefly held Western rights before returning them.","status":"phase-3","asOf":"2026-09-16","links":[{"label":"ClinicalTrials.gov: trials of Lerociclib","url":"https://clinicaltrials.gov/search?intr=GB491"}],"tags":["pipeline","ctgov-ingest"],"related":[],"cancers":["breast-hr-positive"],"sections":[],"technologies":["kinase-inhibitors"],"targets":["cdk4-6"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":["nct05851014"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"notes":[],"provenance":{"editedBy":"OnCo ingestion (ClinicalTrials.gov v2, curated)","editedOn":"2026-09-16"},"code":"GB491","modality":"Oral CDK4/6 inhibitor","mechanism":"Inhibits cyclin-dependent kinases 4 and 6, arresting hormone receptor-positive breast cancer cells in G1, the class of palbociclib, ribociclib and abemaciclib.","approvals":[],"mechanismSteps":[],"toxicity":[],"access":[],"regulatoryEvents":[]},"route":"/drugs/lerociclib/","neighbours":{"cancer":[{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"}],"technology":[{"id":"kinase-inhibitors","kind":"technology","name":"Small-molecule kinase inhibitors","route":"/technologies/kinase-inhibitors/"}],"target":[{"id":"cdk4-6","kind":"target","name":"CDK4/6","route":"/targets/cdk4-6/"}],"trial":[{"id":"nct05851014","kind":"trial","name":"A Study of GB491 in Combination With Letrozole in Patients With HR Positive and HER2 Negative Advanced Breast Cancer","route":"/trials/nct05851014/"}]}}