{"entity":{"id":"tersolisib","kind":"drug","name":"Tersolisib","aka":[],"tldr":"Tersolisib is an experimental small-molecule drug from Eli Lilly and in phase 3 trials for HR-positive / HER2-negative breast cancer, aimed at PIK3CA / PI3K-alpha.","summary":"Tersolisib (STX-478, LY4064809) is a small-molecule drug developed by Eli Lilly and. Its target is PIK3CA / PI3K-alpha (the sponsor names mutant-selective PI3Kalpha (PIK3CA)). The sponsor states: Tersolisib (STX-478/LY4064809) is a mutant-selective PI3Kalpha inhibitor studied as monotherapy and in combination with fulvestrant, with or without CDK4/6-targeted endocrine therapy, in PIK3CA-mutated advanced solid tumours and HR-positive breast cancer. ClinicalTrials.gov describes the intervention as: STX-478 is a mutant-selective PI3Kα inhibitor. It is the investigational product in 2 recruiting or active industry-led phase 2 and phase 3 interventional cancer trials, including the phase 3 study NCT07174336 (A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Advanced Breast Cancer With a Genetic Change (PIK3CA)), in HR-positive / HER2-negative breast cancer. The largest, NCT05768139, plans to enrol 880 participants with primary completion expected 2030-07. Status reflects the highest phase registered on ClinicalTrials.gov; no efficacy results are recorded here.","status":"phase-3","asOf":"2026-09-11","links":[{"label":"ClinicalTrials.gov: trials of Tersolisib","url":"https://clinicaltrials.gov/search?intr=STX-478"}],"tags":["pipeline","ctgov-ingest"],"related":[],"cancers":["breast-hr-positive"],"sections":[],"technologies":[],"targets":["pik3ca"],"drugs":[],"companies":["eli-lilly"],"institutions":[],"pathways":[],"terms":[],"trials":["pik3ca-2"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"provenance":{"editedBy":"OnCo ingestion (ClinicalTrials.gov v2 + sponsor pipeline pages)","editedOn":"2026-09-11"},"code":"STX-478, LY4064809","modality":"small molecule","mechanism":"Tersolisib (STX-478/LY4064809) is a mutant-selective PI3Kalpha inhibitor studied as monotherapy and in combination with fulvestrant, with or without CDK4/6-targeted endocrine therapy, in PIK3CA-mutated advanced solid tumours and HR-positive breast cancer.","approvals":[],"mechanismSteps":[],"toxicity":[],"access":[],"regulatoryEvents":[]},"route":"/drugs/tersolisib/","neighbours":{"cancer":[{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"hr-positive-metastatic-post-cdk46","kind":"cancer","name":"HR-positive metastatic breast cancer after CDK4/6 inhibitors","route":"/cancers/hr-positive-metastatic-post-cdk46/"}],"target":[{"id":"pik3ca","kind":"target","name":"PIK3CA / PI3K-alpha","route":"/targets/pik3ca/"}],"company":[{"id":"eli-lilly","kind":"company","name":"Eli Lilly (incl. Loxo)","route":"/companies/eli-lilly/"}],"trial":[{"id":"pik3ca-2","kind":"trial","name":"A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Advanced Breast Cancer With a Genetic Change (PIK3CA)","route":"/trials/pik3ca-2/"}]}}