Phase III Sister Studies of a Microbicide Ring to Prevent HIV: The Ring Study & ASPIRE
The Ring Study and ASPIRE are the first large-scale clinical trials to assess whether a vaginal ring containing the antiretroviral (ARV) drug dapivirine can safely and effectively protect against the sexual transmission of HIV when used by women for a month at a time. As sister studies, they represent a major step toward a promising female-controlled HIV prevention method that could potentially provide women with discreet, long-acting protection.
Vaginal rings are flexible products that fit comfortably inside the vagina and provide sustained delivery of drugs over a period of time. Vaginal rings are already used in many countries to deliver hormonal contraception. IPM's dapivirine ring adapts that medical technology as a way to fight HIV .
The Ring Study is being conducted by the International Partnership for Microbicides (IPM), which developed the dapivirine ring. ASPIRE (A Study to Prevent Infection with a Ring for Extended Use) is being conducted by the Microbicide Trials Network (MTN) and is funded by the National Institute of Allergy and Infectious Diseases and the National Institute of Mental Health, which are part of the U.S. National Institutes of Health. More than 5,000 women from southern and East Africa will take part in the two studies, which are being conducted in parallel.
The monthly dapivirine ring is the first long-acting ARV-based HIV prevention product to enter efficacy testing and the first involving an ARV other than tenofovir or a tenofovir combination. As the product developer and regulatory sponsor, IPM will seek regulatory approval for the dapivirine ring based on the results from a package of studies of which The Ring Study and ASPIRE are the centerpiece.
Of the more than 35 million people living with HIV, half are women. Women account for 59 percent of adults with HIV in sub-Saharan Africa, where unprotected heterosexual intercourse is the primary driver of the epidemic. Young women are especially vulnerable. Women ages 15 to 24 in sub-Saharan Africa are twice as likely to become infected with HIV than men the same age. Efforts to promote abstinence, monogamy and the use of male condoms have not been enough to stop the HIV epidemic nor are these feasible methods in many settings. Women lack practical and discreet tools they can use to protect themselves from HIV infection.
How the Studies Are Designed
The Ring Study and ASPIRE are, by design, similar in many ways. Both are Phase III trials designed to evaluate the long-term safety and effectiveness of the dapivirine ring when used for one month at a time.
Both studies will also be assessing women’s adherence to and acceptability of the ring.
Women who enroll in either study will be randomly assigned to use either the dapivirine ring or a placebo ring that looks the same but contains no active drug, throughout the duration of the trial.
Both studies are blinded, so neither the women nor the researchers will know which ring participants are using until after the studies are completed. Studies are blinded to ensure the integrity of results.
Both studies were designed with numerous measures to monitor and protect the safety and well-being of participants. Potential study participants will provide informed consent to be screened and to enroll in the study.
Women who choose to participate will be shown how to insert and remove the ring.
At each monthly visit, women will receive a new ring. Women will receive ongoing HIV risk reduction counseling, male condoms, diagnosis and treatment of sexually transmitted infections (STIs), pregnancy testing and family planning services as well as treatment or referrals for medical conditions.
Women who test positive for HIV during either study will immediately stop using the ring, and be referred to local health facilities for care and treatment with an option to enroll in a follow-up study to assess the ring’s impact, if any, on HIV treatment outcomes.
Additional details of each study are described below:
The Ring Study
The Ring Study will enroll approximately 1,650 HIV-negative women, ages 18-45. Women will be randomly assigned to use either the dapivirine ring or a placebo ring; for every two women using the dapivirine ring, one will be using a placebo ring. Women will use the monthly ring to which they are assigned for two years and will receive a new ring at each monthly study visit.
The Ring Study began enrolling women into the trial in April 2012. The study is ongoing at four research centers in South Africa and one in Uganda. The study is expected to release results in 2016.
The Ring Study is being led by Annalene Nel, M.D., Ph.D., IPM’s chief medical officer, based in Cape Town, South Africa, and Saidi Kapiga, M.D., Sc.D., M.P.H., scientific director, Mwanza Intervention Trials Unit, in Mwanza, Tanzania.
ASPIRE will enroll approximately 3,476 HIV-negative women, ages 18-45, who will be randomly assigned in equal number to use either the dapivirine ring or a placebo ring. Women will use their assigned product for at least one year, some for as long as two years.
ASPIRE started screening potential participants in July 2012 and is currently ongoing at 15 MTN-affiliated research sites in South Africa, Uganda and Zimbabwe. Pending necessary approvals, ASPIRE will also be conducted at additional sites in Malawi and Zambia. The researchers expect to complete the study in 2014, with results available later that year or early 2015.
The study is being led by Jared Baeten, M.D., Ph.D., of the University of Washington in Seattle; and Thesla Palanee, Ph.D., of the Wits Reproductive Health and HIV Institute, in Johannesburg, South Africa.
About the Dapivirine Ring
IPM is developing dapivirine for use as a microbicide through a royalty-free licensing agreement with Janssen R&D Ireland.
Dapivirine, also known as TMC-120, belongs to a class of ARVs called non-nucleoside reverse transcriptase inhibitors (NNRTIs) that bind to and disable HIV’s reverse transcriptase enzyme, a key protein needed for HIV replication.
The dapivirine ring is similar to vaginal rings that are used for contraception and hormone replacement in the U.S. and Europe.
The dapivirine ring, made of a flexible silicone material, allows the drug to be slowly released from the ring over time. Studies have shown that the ring can deliver dapivirine to vaginal tissue for a month or longer, with minimal absorption elsewhere in the body.
Studies to date have also shown that use of the dapivirine ring is safe and well-tolerated by women.
The full dapivirine ring licensure program includes The Ring Study and ASPIRE, as well as several smaller studies that will examine the ring’s safety in adolescents and women over 45, condom compatibility and possible drug interactions.
Should the dapivirine ring be found safe and effective, IPM will seek regulatory approval for product licensure and collaborate with key partners to help ensure the ring is made available to women in developing countries at low cost and as soon as possible.
Vaginal microbicides are HIV prevention products being developed for women to help reduce their risk of HIV infection through vaginal sex. To date, clinical trials have primarily focused on microbicides formulated as vaginal gels, with tenofovir gel being the most studied.
In a trial called CAPRISA 004, tenofovir gel successfully reduced HIV risk by 39 percent among women who used the gel before and after sex compared to women who used a placebo gel.
However, in another study known as VOICE (Vaginal and Oral Interventions to Control the Epidemic), which was designed to evaluate daily use of tenofovir gel, as well as daily use of oral tenofovir and oral Truvada, researchers stopped testing tenofovir gel after an independent interim review of study data determined that while safe it was not effective in protecting against HIV among the women in the trial, likely as a result of low levels of adherence to the study regimen.
A third study, FACTS 001, is an ongoing Phase III trial evaluating tenofovir gel when used before and after sex (same regimen used in CAPRISA 004), with results expected in 2014.
Experience in the area of female contraception has demonstrated that women’s preferences differ, and that a product that best suits a woman’s lifestyle and needs is more likely to be used.
Only if a product is used correctly and consistently does it have a chance of being effective. This is why it is important to investigate different HIV prevention strategies.
Some women may prefer using a vaginal gel around the time of sex or taking a daily ARV tablet, while others may prefer a vaginal ring that they replace monthly.