Population Council Projects

PROJECT
CDB-2914 Ring

Data from studies conducted in Population Council laboratories indicate that the potent progesterone receptor modulator CDB-2914 can cross the vaginal mucosa in rabbits. This molecule is being investigated for its potential as a continuous, bleed-free contraceptive for women when delivered through a sustained-release system such as a vaginal ring. In vitro tests of CDB-2914 indicate that it diffuses through the silastic of the ring.

A Phase 1 clinical study of a ring releasing CDB-2914 was completed at two International Committee for Contraception Research (ICCR) clinics, showing that the compound has some activity, but the dose delivered had to be increased. A ring was developed that releases a significantly higher dose, and a clinical trial of this reformulated ring was conducted. Three ICCR clinics in Los Angeles, Santiago, and Santo Domingo each enrolled 13 women who were followed for an initial control cycle, three treatment cycles, and a post-removal follow-up cycle. The study was designed to evaluate the effect of the CDB-2914 ring on pharmacokinetics (the amount of CDB-2914 taken up into the bloodstream), inhibition of ovulation, and bleeding patterns. Follicular function and ovulation inhibition were assessed by ultrasound, and endometrial biopsies were taken prior to and following treatment to assess the effect of this method on the endometrium.

Preliminary findings indicate that the ring had an effect on ovulation, with follicular rupture decreasing in treatment cycles versus the pretreatment control cycle. Subjects were judged to have fairly regular bleeding patterns, though some had long cycles with fewer bleeding and spotting episodes.

Location

Chile, Dominican Republic, United States

Duration

March 2004–May 2005

Population Council researchers

Régine Sitruk-Ware, Patricia Morris, Frederick Schmidt, Yun-yen Tsong

Non-Council collaborators

Indrani Bagchi (University of Illinois at Urbana-Champaign)

Donors

The Lita Annenberg Hazen Foundation

The George J. Hecht Fund

The William and Flora Hewlett Foundation

US National Institutes of Health