NCI Drug Dictionary

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The NCI Drug Dictionary contains technical definitions and synonyms for drugs/agents used to treat patients with cancer or conditions related to cancer. Each drug entry includes links to check for clinical trials listed in NCI's List of Cancer Clinical Trials.

immediate-release onapristone
An immediate-release (IR) formulation of onapristone, an orally bioavailable progesterone receptor (PR) antagonist, with antineoplastic activity. Onapristone binds to the PR and inhibits both PR activation and the associated expression of PR-responsive genes. This may inhibit PR-mediated proliferative effects in cancer cells overexpressing PR. PR is expressed in certain cancer cell types and plays a key role in proliferation and survival. Check for active clinical trials or closed clinical trials using this agent. (NCI Thesaurus)
Synonyms:IR onapristone
onapristone, immediate-release formulation