This is a double-blind, randomized, placebo-controlled Phase I/II study to assess the safety of a silicone elastomer vaginal ring containing 25mg dapivirine.

Inclusion Criteria:

• Women between 18 and 40 years of age inclusive who can provide informed consent
• Available for all visits and consent to follow all procedures scheduled for the study
• Healthy and self-reported sexually active
• HIV-negative
• On a stable form of contraception and willing to continue OR have undergone surgical sterilization at least 3 months prior to enrollment
• In the absence of the use of exogenous hormone(s), have a self-reported regular menstrual cycle defined as having a minimum of 21 days and a maximum of 35 days between menses
• Upon pelvic/speculum examination and colposcopy at the time of enrolment, the cervix and vagina appear normal as determined by the investigator
• Asymptomatic for genital infections at the time of enrolment
• Willing to refrain from use of vaginal products or objects within 14 days from enrollment and for the duration of the study
• Willing to answer to acceptability, adherence and behavioural assessments throughout the study
• Willing to refrain from participation in any other research study for the duration of their participation
• Willing to provide adequate locator information for study retention purposes and be reachable per local standard procedures

Exclusion Criteria:

• Currently pregnant or last pregnancy within 3 months prior to enrolment
• Currently breast-feeding
• Participated in any other research study within 60 days prior to screening
• Previously participated in any HIV vaccine study
• Untreated urogenital infections within 2 weeks prior to enrolment
• Presence of any abnormal physical finding on the vulva, vaginal walls or cervix during pelvic/speculum examination and/or colposcopy
• History of significant urogenital or uterine prolapse, undiagnosed vaginal bleeding, or urethral obstruction, incontinence or urge incontinence
• Pap smear result at screening that requires cryotherapy, biopsy, treatment or further evaluation
• Any Grade 2, 3 or 4 baseline (screening) haematology, chemistry or urinalysis laboratory abnormality according to the DAIDS Table for Grading Adverse Events
• Any abnormal bleeding per vagina, bleeding per vagina during or following vaginal intercourse, or gynaecologic surgery within 90 days prior to enrolment
• Any history of anaphylaxis or severe allergy resulting in angioedema; or a history of sensitivity/allergy to latex or silicone elastomer
• Any serious acute, chronic or progressive disease
• Any condition(s) that, in the opinion of the investigator, might interfere with adherence to study requirements or evaluation of the study objectives