Telapristone is an orally available 21-substituted-19-nor-progestin and selective progesterone receptor modulator (SPRM), with potential anti-progesterone and antineoplastic activities. Its acetate form, the telapristone Acetate is a clinically used and a studied drug.

Onapristone is a type I progesterone receptor (PR) antagonist that prevents PR- mediated DNA transcription and was studied as an antitumor agent. This drug possessed activity in breast cancer and is participating in phase II clinical trials to test any good and bad effect for the treatment of endometrial cancer, ovarian cancer, peritoneal cancer, and prostate cancer.

Toripristone has a high inhibiting activity against the cortisol receptors. Toripristone enhanced the antibacterial activities of the sparfloxacin in combination with ethambutol in the treatment of M. avium complex infections. Also, toripristone is a glucocorticoid type II receptor and progesterone receptor antagonist. Toripristone treatment was estimated to selectively occupy approximately 50% of glucocorticoid receptors in rat brain.

Tanaproget (WAY-166989) is a nonsteroidal progesterone receptor agonist. It has been in Phase-II clinical trials as an oral contraceptive. The compound demonstrated a positive preclinical pharmacological profile in the treatment of endometriosis. The level of progesterone receptors in breast tumours can be used to guide the selection of endocrine therapies for breast cancer patients. Radiolabeled analogues of tanaproget have diagnostic potential as PET imaging agents for breast cancer.

Lonaprisan is an orally bioavailable pentafluoroethyl derivative of a mifepristone-related steroid with antiprogestagenic activity. Lonaprisan is a pure, highly receptor-selective progesterone receptor (PR) antagonist (both PR isoforms PR-A and PR-B); binding of this agent to PRs inhibits PR activation and the associated proliferative effects. Lonaprisan showed limited efficacy as second-line endocrine therapy in postmenopausal women with PR-positive metastatic breast cancer. Lonaprisan had been in phase II clinical trials by Bayer for the treatment of breast cancer and dysmenorrhea. However, this research has been discontinued.

Asoprisnil (J867) is a novel selective steroid receptor modulator that shows unique pharmacodynamic effects in animal models and humans. Asoprisnil, its major metabolite J912, and other structurally related compounds represent a new class of progesterone receptor (PR) ligands that exhibit partial agonist and antagonist activities in vivo. Asoprisnil demonstrates a high degree of receptor and tissue selectivity, with a high-binding affinity for PR, moderate affinity for glucocorticoid receptor (GR), low affinity for androgen receptor (AR), and no binding affinity for estrogen or mineralocorticoid receptors. This compound was recently in clinical trials for the treatment of uterine fibroids and endometriosis, but those studies were discontinued.