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Dapivirine vaginal ring eyed for HIV prevention
Two sister studies have been launched in Africa to evaluate the ability of a new monthly vaginal ring containing the antiretroviral drug dapivirine to safely prevent new HIV infections in women.
The Ring Study, under the aegis of the Silver Springs, MD-based International Partnership for Microbicides (IPM), plans to enroll a total of 1,650 women at four sites in South Africa. Researchers look to start enrollment at additional sites in Rwanda and Malawi, pending regulatory and ethics approvals. The second study, known as ASPIRE (A Study to Prevent Infection with a Ring for Extended Use) is being led by the Microbicide Trials Network, based at Magee — Womens Research Institute and the University of Pittsburgh (PA). Investigators plan to conduct the study at 17 sites in Malawi, Uganda, South Africa, Zambia, and Zimbabwe. The ASPIRE trial is designed to enroll approximately 3,476 women.
Both trials will look at women ages 18 to 45, all who will be randomly assigned to use the dapivirine ring or a placebo device. Participants will be instructed how to insert and remove the ring, which they will replace every four weeks. All participants will receive ongoing HIV risk reduction counseling, condoms, and diagnosis and treatment of sexually transmitted infections.
The two studies are the first effectiveness trials of a vaginal ring for HIV prevention, say study officials. The two studies also represent the first large-scale prevention trials involving an antiretroviral other than tenofovir or a tenofovir combination.
Ring offers benefits
The ring, developed by IPM, uses an innovative delivery method to slowly release the drug over one month. Dapivirine is in the class of antiretroviral drugs known as non-nucleoside reverse transcriptase inhibitors, all which have long been used to successfully treat HIV-1 and prevent mother-to-child transmission.
The ring has a number of attractive features for HIV prevention, both for its usability and for its potential HIV protective effects, observes Jared Baeten, MD, PhD, associate professor in the Departments of Global Health and Medicine at the University of Washington in Seattle. He, along with Thesla Palanee, PhD, of the Wits Reproductive Health and HIV Institute in Johannesburg, South Africa, are leading the ASPIRE trial.
The ring offers ease of use, says Baeten. It is a method that women will not have to remember to use on a daily basis, and it is discreet, representing a method that can be used privately and under a woman's control. With drug delivery administered at the site of HIV exposure, the ring can be a "quite powerful" tool in HIV prevention, Baeten observes.
The sister trials are being run as part of a comprehensive licensure program that will involve thousands of women in its approximate three-year span. In addition to the Ring Study and the ASPIRE study, the program also will include studies to examine the ring's safety in adolescents and peri- and postmenopausal women, condom compatibility, and drug-drug interactions. If the study results show the ring to be safe and effective, IPM will seek regulatory approval for product licensure and work with other partners to see that the ring is made available at low cost to women in developing countries as soon as possible.
Zeda Rosenberg, ScD, chief executive officer at IPM, explains, "Regulatory approval for products by the Food and Drug Administration, European Medicines Agency, and especially African national regulatory agencies requires adequate and well-controlled trials to determine safety and efficacy of a product, and [the agencies'] strong preference is to have two trials that are run in parallel to determine the efficacy."
IPM has agreement with Janssen R&D
IPM is developing dapivirine for use as a microbicide through a royalty-free licensing agreement with Janssen R&D Ireland (formerly Tibotec Pharmaceuticals), one of the Janssen pharmaceutical companies of Johnson & Johnson. It also is developing multipurpose technologies, including a 60-day dapivirine-contraceptive ring under a grant from USAID.
The combination contraceptive/HIV prevention ring is now in pre-clinical studies, says Rosenberg. If the dapivirine ring does receive approval for HIV prevention, proponents hope to move forward quickly with development of the combination device, she notes.
HIV/AIDS is the leading cause of death globally in women ages 15-44.1 It exacts a high toll in sub-Saharan Africa, where young women are at least twice as likely to become infected as young men.2
In a statement accompanying The Ring Study announcement, Annalene Nel, MD, PhD, chief medical officer at IPM, said, "We are very excited that this program is now underway and that the ring has the potential to be groundbreaking for women in Africa. This product could expand the menu of HIV prevention options and give women a very practical way to protect their own health."