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Inactive
Last updated: May 18, 2026

Onapristone

ZK 98 299

  • User: Female
  • Hormonal: Hormonal
  • Delivery type:
    • Undetermined
  • Intended Duration:
    • Undetermined
  • Development Stage: Pre-Clinical
  • Developer(s)/researcher(s): Schering AG
Details
  • API: Onapristone
  • Target: Progesterone Receptor
  • Mechanism of Action:
    • Ovulation Inhibition
    • Cervical Mucus Changes
    • Endometrial Changes
  • Inactive Materials: Benzyl Benzoate, Castor Oil
  • Regimen: Undetermined
  • MPT: Not Potential MPT
Product Status

More recent publications reference negative impact on liver health as a reason for the discontinuation of contraceptive research

History

See linked literature below for information on safety and biocompatibility

Development for contraceptive indication was discontinued in early 2000s. Onapristone was in Phase II trials for prostate cancer and is now in clinical trials for the treatment of breast cancer.

Publications