13-cycle, 1-year contraceptive vaginal system proves effective in phase 3 trials

  • Lancet Public Health

  • de Emily Willingham, PhD
  • Clinical Essentials
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Takeaway

  • A contraceptive vaginal system using segesterone acetate and ethinyl estradiol (Annovera) is effective for 13 cycles of use, according to findings from 2 pivotal phase 3 trials . 
  • The FDA approved the system in 2018, but these studies included non-US sites as well.

Why this matters

  • The ring-shaped system does not require refrigeration when not being used, requires only annual refills.

Key results

  • Pearl index: 2.98 per woman-years (95% CI, 2.13-4.06), which authors say is well within the range indicating efficacy.
  • Index was worst among youngest women, black women, and those who removed the system longer than 2 hours during the active 21-day time frame.
  • System was 97.5% effective. 
  • Return to menses or desired conception after cessation occurred among all 290 follow-up participants within 6 months.
  • Adverse events included headache, fatigue, nausea, vaginal discharge, abdominal pain. 

Study design

  • Identically designed, multicenter, open-label phase 3 trials at US sites (15; December 19, 2006 to October 9, 2009) and at US and international sites (12; November 1, 2006 to July 2, 2009); enrolled 2278 healthy, sexually active, nonpregnant people ages 18-40 years.
  • Funding: NIH, WHO, others.

Limitations

  • Exclusion of women with BMI >29.0 kg/m2 might limit generalizability.