Comparative safety, efficacy, and cycle control of Lunelle™ monthly contraceptive injection (medroxyprogesterone acetate and estradiol cypionate injectable suspension) and Ortho-Novum® 7/7/7 oral contraceptive (norethindrone/ ethinyl estradiol triphasic)

Abstract

An open-label, nonrandomized, parallel, controlled study compared the efficacy, safety, and cycle control of a new monthly injectable contraceptive containing 25 mg of medroxyprogesterone acetate (MPA) and 5 mg of estradiol cypionate (E 2C) (MPA/E 2C) (Lunelle™ Monthly Contraceptive Injection) with that of a norethindrone 0.5, 0.75, 1.0 mg/0.035 mg ethinyl estradiol (NET/EE) triphasic oral contraceptive (Ortho-Novum® 7/7/7). At study enrollment, women chose either the injections or the oral contraceptive. A higher proportion of women in the NET/EE group (65.1%) than in the MPA/E 2C group (43.7%) had used hormonal contraception during the month before the study (p <0.01). Overall, 55.5% (434/782) of MPA/E 2C users and 67.6% (217/321) of NET/EE users completed the 60-week trial. One-year contraceptive efficacy (13 cycles of 28 days) for MPA/E 2C and NET/EE was based on 8008 and 3434 woman-cycles of use, respectively. During the first year, one pregnancy occurred in an NET/EE user for a lifetable rate of 0.3; no pregnancies occurred in users of MPA/E 2C. One additional pregnancy in the NET/EE group occurred during the 15th treatment cycle. After the first treatment cycle, women in both groups experienced regular menses, with an average cycle length of 28 days in MPA/E 2C users and 27 days in NET/EE users. Although MPA/E 2C users were more likely to experience bleeding irregularities, only 2.5% (19/775) cited metrorrhagia as a reason for discontinuing treatment. The adverse events reported in both treatment groups are consistent with those expected with the use of combined hormonal contraceptives. Overall, the results of this first Phase III US clinical trial of MPA/E 2C confirm this method’s high contraceptive efficacy and safety, as shown in previous studies by the World Health Organization. These results suggest that a monthly combination injectable would represent a welcome new contraceptive option for women in the US.