{"entity":{"id":"sierra-oncology","kind":"company","name":"Sierra Oncology","aka":["Sierra Oncology, Inc.","Sierra Oncology LLC","ProNAi Therapeutics"],"tldr":"A former California company that developed momelotinib, a pill for myelofibrosis, a bone marrow cancer, especially for patients with anaemia. GSK bought it in 2022.","summary":"Sierra Oncology was a California-based biopharmaceutical company focused on targeted therapies for rare forms of cancer, listed on Nasdaq as SRRA. Its lead asset was momelotinib, which GSK describes as inhibiting ACVR1/ALK2, JAK1 and JAK2, developed for myelofibrosis patients with anaemia; in January 2022 Sierra announced that the Phase 3 MOMENTUM trial (NCT04173494) met its primary and key secondary endpoints. GSK agreed on 13 April 2022 to acquire Sierra for $55 per share in cash, about $1.9 billion in equity value, and announced on 1 July 2022 that the acquisition was complete, after Sierra shareholders approved it on 29 June 2022. SEC records list ProNAi Therapeutics as the company's earlier name until January 2017.","asOf":"2026-11-04","links":[{"label":"GSK press release: agreement to acquire Sierra Oncology, 13 April 2022","url":"https://www.gsk.com/en-gb/media/press-releases/gsk-reaches-agreement-to-acquire-late-stage-biopharmaceutical-company-sierra-oncology-for-19bn/"},{"label":"GSK completes acquisition of Sierra Oncology (SEC Form 6-K, 1 July 2022)","url":"https://www.sec.gov/Archives/edgar/data/1131399/000165495422009090/a0772r.htm"},{"label":"SEC EDGAR filings","url":"https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001290149"},{"label":"RA Capital portfolio entry","url":"https://www.racap.com/portfolio/sierra-oncology"}],"tags":[],"related":[],"cancers":["primary-myelofibrosis"],"sections":["targeted-therapy"],"technologies":["kinase-inhibitors"],"targets":[],"drugs":["momelotinib"],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":["momentum"],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["The company website is gone; the acquirer's releases are the sources.","Founding year not read from a primary source.","Many earlier momelotinib, SRA737 and PNT2258 trials now list 'Sierra Oncology LLC - a GSK company' as sponsor on ClinicalTrials.gov; only MOMENTUM is a trial record in OnCo."],"hq":"San Mateo, CA","country":"US","companyType":"biotech","stage":"acquired","investors":["ra-capital"],"funding":[],"acquiredBy":"gsk"},"route":"/companies/sierra-oncology/","neighbours":{"cancer":[{"id":"primary-myelofibrosis","kind":"cancer","name":"Primary myelofibrosis","route":"/cancers/primary-myelofibrosis/"}],"section":[{"id":"targeted-therapy","kind":"section","name":"Targeted Therapy","route":"/fronts/targeted-therapy/"}],"technology":[{"id":"kinase-inhibitors","kind":"technology","name":"Small-molecule kinase inhibitors","route":"/technologies/kinase-inhibitors/"}],"drug":[{"id":"momelotinib","kind":"drug","name":"Momelotinib","route":"/drugs/momelotinib/"}],"trial":[{"id":"momentum","kind":"trial","name":"MOMENTUM","route":"/trials/momentum/"}],"company":[{"id":"gsk","kind":"company","name":"GSK","route":"/companies/gsk/"},{"id":"ra-capital","kind":"company","name":"RA Capital Management","route":"/companies/ra-capital/"}]}}