Study of Safety and Efficacy of an Oral Contraceptive


This is a comparative study. The primary objective of the study is to assess the efficacy of a low dose oral contraceptive in the prevention of pregnancy. The secondary objectives are to assess the incidence of intracyclic bleeding of norethindrone acetate/ethinyl estradiol (NETA/EE) administered for 24 days and NETA/EE administered for 21 days; and to assess the safety and tolerability of the product.

Full Title of Study: “Open Label, Randomized, Comparator-Controlled Study of the Contraceptive Efficacy of Norethindrone Acetate (NA) and Ethinyl Estradiol (EE)”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: None (Open Label)
  • Study Primary Completion Date: November 2004


  • Drug: Norethindrone Acetate/Ethinyl Estradiol 24 Days
    • One tablet per day for 24 days of each 28 day cycle followed by 4 placebo tablets
  • Drug: Norethindrone Acetate /Ethinyl Estradiol 21 Days
    • One tablet per day for 21 days of each 28 day cycle followed by 7 placebo tablets

Arms, Groups and Cohorts

  • Experimental: 24 Day NA/EE
    • Norethindrone acetate 1 mg /ethinyl estradiol 20 mcg for 24 days of each 28 day cycle
  • Active Comparator: 21 Day NA/EE
    • Norethindrone acetate 1 mg/ethinyl estradiol 20 mcg for 21 days of each 28 day cycle

Clinical Trial Outcome Measures

Primary Measures

  • Pregnancy Rate (Expressed as Pearl Index) for Women 18 to 45 Years Old, MITT Population
    • Time Frame: 5.6 months (6 – 28 day cycles)
    • Pearl Index = 1300 * number of pregnancies/number of women-cycles of treatment

Secondary Measures

  • Mean Number of Intracyclic Bleeding (IB)/Spotting Days in Cycles 2-6, MITT Population
    • Time Frame: 5.6 months (6 – 28 day cycles)
    • Self-reported via patient completed diary (none – no vaginal bleeding, light – less than normal menstruation, normal – like normal menstruation, heavy – more than normal menstruation) along with daily use of sanitary protection (other than panty liners). Light bleeding requiring no more than single pad or tampon will be spotting.

Participating in This Clinical Trial

Inclusion Criteria

  • Healthy Women – Age 18-45 – At risk for pregnancy – History of regular cycles Exclusion Criteria:

  • Contraindications for use of hormonal contraception – Conditions which affect the absorption or metabolism of steroid hormones – BMI > 35

Gender Eligibility: Female

Minimum Age: 18 Years

Maximum Age: 45 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Warner Chilcott
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Herman Ellman, MD, Study Director, Sponsor GmbH

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