{"entity":{"id":"callio-therapeutics","kind":"company","name":"Callio Therapeutics","aka":[],"tldr":"Callio Therapeutics makes antibodies that carry two different cancer-killing drugs at once to HER2-positive tumours, to stop cancers escaping treatment. Its first medicine entered human trials in 2026.","summary":"Callio Therapeutics is a clinical-stage biotech headquartered in Seattle and Singapore, launched in March 2025 by Frazier Life Sciences with technology and programmes exclusively licensed from Hummingbird Bioscience. Its platform pairs a modular linker with two rationally selected synergistic payloads on one antibody, aiming to block the dominant resistance mechanisms that limit single-payload ADCs. The lead candidate CLIO-8221 is a HER2-targeted dual-payload ADC co-delivering exatecan (a topoisomerase 1 inhibitor) and an ATR inhibitor; a phase 1/2 study in advanced HER2-expressing solid tumours was presented as a trials-in-progress poster at ASCO 2026 after preclinical data at AACR 2026. A second undisclosed ADC programme is also funded. The USD 187 million Series A was led by Frazier Life Sciences with significant participation from Jeito Capital. Zachary Hornby was appointed CEO in September 2026.","asOf":"2026-09-10","links":[{"label":"Official website","url":"https://calliotx.com/"},{"label":"Series A press release","url":"https://www.prnewswire.com/news-releases/callio-therapeutics-launches-with-us187-million-series-a-to-advance-multi-payload-antibody-drug-conjugate-platform-through-clinical-proof-of-concept-302388161.html"},{"label":"News and publications","url":"https://calliotx.com/news/"}],"tags":[],"related":[],"cancers":["breast-her2-positive"],"sections":["adcs"],"technologies":["dual-payload-adc","adc"],"targets":["her2","atr"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":["nct07300943"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hq":"Seattle, WA","country":"US","companyType":"biotech","website":"https://calliotx.com/","stage":"startup","investors":["frazier-life-sciences","jeito-capital","novo-holdings","omega-funds"],"funding":[{"round":"Series A","year":2025,"amountUsd":187000000,"source":"https://www.prnewswire.com/news-releases/callio-therapeutics-launches-with-us187-million-series-a-to-advance-multi-payload-antibody-drug-conjugate-platform-through-clinical-proof-of-concept-302388161.html"}]},"route":"/companies/callio-therapeutics/","neighbours":{"cancer":[{"id":"breast-her2-positive","kind":"cancer","name":"HER2-positive breast cancer","route":"/cancers/breast-her2-positive/"}],"section":[{"id":"adcs","kind":"section","name":"Antibody-Drug Conjugates","route":"/fronts/adcs/"}],"technology":[{"id":"adc","kind":"technology","name":"Antibody-drug conjugate (ADC)","route":"/technologies/adc/"},{"id":"dual-payload-adc","kind":"technology","name":"Dual-payload ADC","route":"/technologies/dual-payload-adc/"}],"target":[{"id":"atr","kind":"target","name":"ATR","route":"/targets/atr/"},{"id":"her2","kind":"target","name":"HER2","route":"/targets/her2/"}],"trial":[{"id":"nct07300943","kind":"trial","name":"Study in Advanced Solid Tumor Patients","route":"/trials/nct07300943/"}],"company":[{"id":"frazier-life-sciences","kind":"company","name":"Frazier Life Sciences","route":"/companies/frazier-life-sciences/"},{"id":"jeito-capital","kind":"company","name":"Jeito Capital","route":"/companies/jeito-capital/"},{"id":"novo-holdings","kind":"company","name":"Novo Holdings","route":"/companies/novo-holdings/"},{"id":"omega-funds","kind":"company","name":"Omega Funds","route":"/companies/omega-funds/"}]}}