NCIt definition : An orally bioavailable pentafluoroethyl derivative of a mifepristone-related steroid
with antiprogestagenic activity. Lonaprisan is a pure, highly receptor-selective progesterone
receptor (PR) antagonist; binding of this agent to PRs inhibits PR activation and
the associated proliferative effects. Unlike many other antiprogestins such as mifepristone,
this agent does not appear to convert to an agonist in the presence of protein kinase
A (PKA) activators and shows high antiprogestagenic activity on both progesterone
receptor (PR) isoforms PR-A and PR-B.;