Maintenance of consistent ovulation inhibition with the 75 mcg
desogestrel-only contraceptive pill Cerazette® after scheduled 12-hour delays
in tablet-intake
T. Korver (1), C. Klipping (2), I. Heger-Mahn (3), I. Duijkers (2), G.
van Osta (4)
Clinical Development Department, NV Organon, Oss, The Netherlands (1);
Dinox Medical Investigations, Nijmegen, The Netherlands (2); Dinox GmBH, Berlin,
Germany (3); Biometrics Department, NV Organon, Oss, The Netherlands (4)
Introduction: Cerazette® is an estrogen-free, desogestrel-only
contraceptive pill which differs from existing progestagen-only pills (POPs) in
providing consistent ovulation inhibition. Traditional POPs primarily rely on
the induction of a viscous cervical mucus, which hampers the penetration of
sperm into the female genital tract. This contraceptive action is considered to
last for maximally 27 hours after intake and therefore delays in tablet intake
of only 3 hours may jeopardize contraceptive efficacy. This study was performed
to demonstrate that Cerazette® is more failure-proof than traditional POPs due
to its ovulation-inhibitory properties. To this end, the incidence of ovulation
during 2 treatment cycles during which three tablets were to be taken 36 hours
after the previous one (i.e. 12 hours late) was determined, as well as the time
required for ovulation to return after intake of the last tablet.
Design and methods: A total of 103 women aged between 19 and 40 years
with confirmed ovulation were admitted to this openlabel pharmacodynamic study.
They were treated with Cerazette® for 56 days with three tablets to be taken 12
hours late, randomised to a regimen with scheduled late tablets on Days 39, 42,
49 (Group A) or on Days 11, 14 and 21 (Group B). Ovulation was assessed by
measuring progesterone P serum levels every other day. P levels >16 nmol/L,
sustained for at least 5 days were taken to indicate ovulation. P sampling was
continued until return of ovulation was observed after stopping treatment.
Results: One of the 103 treated subjects ovulated twice during
treatment. The ovulation incidence thus amounts to 1.0% (twosided 95% confidence
interval 0.02–5.29%). There was no apparent relationship between these
ovulations and scheduled late tablets. The minimum time to first post-treatment
ovulation was 7 days, while it took 17.2 days on average from last tabletintake
until ovulation. Conclusion: The estrogen-free pill Cerazette® provides
consistent ovulation inhibition, even when tablets are incidentally taken 12
hours late. In fact, return of ovulation takes at least 7 days. With these
properties, Cerazette® appears to be as effective as combined OCs in preventing
ovulation.
