A Proof-of-Concept Study of Ulipristal Acetate for Early Medication Abortion

The current regimen for early medication abortion in many countries is mifepristone and misoprostol, but mifepristone is relatively expensive and limited in many regions. Ulipristal acetate, with a similar chemical profile, might be an alternative. This proof-of-concept study evaluated ulipristal acetate and misoprostol for medication abortion through 63 days of gestation.

We conducted a two-stage clinical study to choose an effective and acceptable ulipristal-misoprostol regimen. First, we undertook a dose-finding study. Sixty-six participants were randomly assigned to either 60 mg or 90 mg of oral ulipristal, followed by 800 μg of buccal misoprostol. Because the two groups had similar efficacy and safety profiles, we opted for the 60-mg ulipristal dose for an open-label study with 100 additional participants, resulting in a total of 133 participants using the same regimen. To evaluate acceptability, we applied a structured questionnaire at the end of the follow-up visit.

Pregnancy termination occurred with the combination of oral ulipristal 60 mg and buccal misoprostol 800 μg in 129 out of 133, or 97.0%, (95% confidence interval [CI], 94.1 to 99.9%), of participants. Among those for whom this regimen did not result in pregnancy termination, one participant had a completion with sharp curettage, two received manual vacuum aspiration, and one underwent a repeat medication abortion with misoprostol alone. Side effects included chills (77.4%; 95% CI, 70.3 to 84.5%), diarrhea (66.9%; 95% CI, 59.0 to 74.8%), and nausea (48.1%; 95% CI, 39.7 to 56.5%). No serious adverse events were reported. The regimen was deemed "acceptable" or "highly acceptable" by 97.7% (95% CI, 95.2 to 100.0%) of participants.

This study suggests that ulipristal acetate followed by misoprostol is an effective and acceptable medication abortion regimen with no reported serious adverse events. (This project is supported by the OPTions Initiative. The study registered as ISRCTN35625202.).