{"entity":{"id":"clio-8221","kind":"drug","name":"CLIO-8221","aka":[],"tldr":"CLIO-8221 is an experimental dual-payload antibody-drug conjugate from Callio Therapeutics, in phase 1 trials for HER2-expressing advanced solid tumours and metastatic breast cancer.","summary":"CLIO-8221 is a dual-payload antibody-drug conjugate from Callio Therapeutics, with Hummingbird Bioscience as partner. A HER2-targeted ADC carrying two payloads at once, the topoisomerase 1 inhibitor exatecan and the ATR inhibitor berzosertib, paired to address resistance that emerges on existing HER2 ADCs. Its furthest stage is phase 1, for HER2-expressing advanced solid tumours and metastatic breast cancer. ClinicalTrials.gov registers it in one study linked below. Phase 1/2 recruiting in the US and Australia, China planned (NCT07300943). Whether it works in people has not been established unless a trial below reports it.","status":"phase-1","asOf":"2026-11-03","links":[{"label":"Callio Therapeutics: calliotx.com","url":"https://calliotx.com/"},{"label":"Callio Therapeutics: biospace.com","url":"https://www.biospace.com/press-releases/callio-therapeutics-to-present-phase-1-trial-design-of-clio-8221-novel-dual-payload-adc-at-asco-2026"},{"label":"Callio Therapeutics: biospace.com","url":"https://www.biospace.com/press-releases/callio-therapeutics-to-present-phase-1-trial-design-of-clio-8221-novel-dual-payload-adc-at-asco-2026"},{"label":"Callio Therapeutics: clinicaltrials.gov","url":"https://clinicaltrials.gov/study/NCT07300943"},{"label":"ClinicalTrials.gov: trials of CLIO-8221","url":"https://clinicaltrials.gov/search?intr=CLIO-8221"}],"tags":["pipeline","ctgov-ingest"],"related":[],"cancers":["metastatic-cancer"],"sections":[],"technologies":[],"targets":["her2"],"drugs":[],"companies":["callio-therapeutics"],"institutions":[],"pathways":[],"terms":[],"trials":["nct07300943"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"provenance":{"editedBy":"OnCo gap audit, class 5 (company pipeline pages and ClinicalTrials.gov v2)","editedOn":"2026-11-03"},"code":"CLIO-8221","modality":"Dual-payload antibody-drug conjugate","mechanism":"A HER2-targeted ADC carrying two payloads at once, the topoisomerase 1 inhibitor exatecan and the ATR inhibitor berzosertib, paired to address resistance that emerges on existing HER2 ADCs.","approvals":[],"mechanismSteps":[],"toxicity":[],"access":[],"regulatoryEvents":[]},"route":"/drugs/clio-8221/","neighbours":{"cancer":[{"id":"metastatic-cancer","kind":"cancer","name":"Metastatic cancer (cancer that has spread)","route":"/cancers/metastatic-cancer/"}],"target":[{"id":"her2","kind":"target","name":"HER2","route":"/targets/her2/"}],"company":[{"id":"callio-therapeutics","kind":"company","name":"Callio Therapeutics","route":"/companies/callio-therapeutics/"}],"trial":[{"id":"nct07300943","kind":"trial","name":"Study in Advanced Solid Tumor Patients","route":"/trials/nct07300943/"}]}}