Mifepristone treatment improves length and quality of survival of mice with spontaneous leukemia.

Background: Mifepristone was found to suppress expression of the progesterone-induced blocking factor (PIBF). Progesterone-induced blocking factor suppresses natural killer cell activity. The objective of the present study was to determine if treatment of mice with spontaneous murine lymphocyte leukemia with the progesterone receptor antagonist mifepristone could improve length and quality of life.

Materials And Methods: Sixty-one mice were gavaged with mifepristone and 33 controls with olive oil. Quality of life was determined by body conditioning score (BCS). Treatment was initiated when the mice were 6 months old.

Results: Within 2 weeks of therapy only 11.4% of the mifepristone treated mice died vs. about 50% of controls. The BCS was 5 (highest quality) in 82% of treated mice vs. 11% of controls after 2 weeks of therapy.

Conclusion: Mifepristone therapy should be further evaluated for treating leukemia and lymphoma.