A Study to Assess Contraceptive Efficacy and Safety of Etonogestrel (ENG) Implant Beyond 3 Years of Use (MK-8415-060)

The primary purpose of this study is to assess the efficacy and safety of the etonogestrel (ENG) contraceptive implant during participants' fourth and fifth years of use when used as the only method of contraception. The ENG implant is currently approved for a 3-year duration, and this study aims to confirm available evidence suggesting that the ENG implant remains highly effective when used up to 5 years.


Eligibility Criteria:
Inclusion Criteria:

* Not diagnosed with perimenopause or menopause.
* Heterosexually active with a partner who is not known to be subfertile, sterilized, or infertile, and is seeking contraception for pregnancy.
* Palpable intact ENG implant in the upper inner-arm for 36 months from the date of insertion at the time of enrollment, and has documentation of the insertion date (for example, Nexplanon user card or medical record completed on the date of insertion).
* Does not desire a pregnancy within the 24 months after enrollment, is willing to continue use of the implant for an additional 24 months, and is not intending to use any other form of contraception (eg, condoms) from enrollment until after implant removal at 24 months post enrollment.
* Good physical and mental health in the medical judgment of the investigator.
* History of regular menstrual cycles of 21 to 35 days before the insertion of the ENG implant or before hormonal contraceptive use (which may have preceded the current implant use).
* Able and willing to adhere to all required study procedures, including study visits and eDiary entries, and not planning to relocate during the study.

Exclusion Criteria:

* Conceived a pregnancy during use of the current implant or a past contraceptive implant.
* Known or suspected pregnancy at the time of screening or enrollment visit.
* History of subfertility or infertility.
* Breastfeeding.
* Untreated gonorrhea, chlamydia, or trichomonas or symptomatic vaginitis/cervicitis.
* Significantly abnormal cervical cytology (Pap) or pathology results either at screening or documented in the 36-month period prior to enrollment.
* Current use of an intrauterine device/intrauterine system (IUD/IUS).
* Presence of more than one ENG implant.
* Use of daily/monthly hormonal contraceptives, sex steroids, or GnRH agonist/antagonist within 3 months prior to enrollment.
* Use of injectable hormonal contraceptive with 3-month duration within 9 months prior to enrollment.
* Use of injectable GnRH agonist with 3-month duration within 10 months prior to enrollment .
* Use of medications that induce liver enzymes within 2 months prior to enrollment.
* Untreated or unresolved vaginal bleeding or spotting attributable to underlying pathology in the 12 months before screening.
* Frequent, prolonged, or excessive vaginal bleeding/spotting in the 12 months prior to screening which has not been evaluated to detect underlying pathology.
* History of venous thromboembolism or arterial thromboembolism, transient ischemic attack, angina pectoris, or claudication.
* Any condition associated with an increased risk of venous thromboembolism.
* Uncontrolled or severe hypertension at screening visit.
* Clinically significant liver disease, including active viral hepatitis or cirrhosis.
* History of malignancy within 5 years before screening, except treated skin cancer.
* History of sex steroid-influenced malignancies (eg, genital organs, breasts).
* History or presence of liver tumors (benign or malignant).
* Known allergy/sensitivity or contraindication to the ENG implant or lidocaine with epinephrine.
* History of drug or alcohol abuse or dependence within 24 months prior to enrollment. Routine use of alcohol or marijuana that is not considered abuse or dependence is not exclusionary.
* Use of an investigational drug within 2 months prior to enrollment. Long-term follow up of an investigational compound for COVID-19 is allowed 2 months after the last administered dose.
* Staff or immediate family members of the investigational site or Sponsor directly involved with this study.