CONRAD Head of drug delivery, Meredith Clark, PhD, today presented preclinical data on the new intravaginal ring that provides contraception in addition to HIV-1 and HSV-2 prevention at the 2013 American Association of Pharmaceutical Scientists (AAPS) Annual Meeting and Exposition in San Antonio, Texas. This multipurpose prevention technology (MPT) usually stays within the vagina for approximately 90 days and releases the contraceptive levonorgestrel (LNG) and tenofovir (TFV), an antiretroviral that inhibits HIV and HSV replication in susceptible cells.
The CONRAD product team, together with Dr. Patrick Kiser at Northwestern University, performed in vitro release testing and 3-month pharmacokinetic (PK) studies of the ring in rabbits and sheep, and compared drug levels to those seen with utilization of tenofovir gel. The PK studies discovered that levels of tenofovir within the target tissue delivered in the ring are similar or higher compared to those obtained after TFV 1% gel application, a product that has proven to work in preventing HIV and HSV infections in females. Additionally, discharge of the contraceptive agent seemed to be in line with previous levels tested to become efficacious in females. Stability studies will continue and result in Phase I numerous studies in females in 2014, which will test the combination ring, in addition to a tenofovir-only ring.
Tenofovir may be the first microbicide shown to be efficacious in humans, with the CAPRISA 004 clinical trial showing that ladies using the gel pre and post sex reduced their chance of HIV infection by 39-54%. CAPRISA 004 also showed the gel to become 51% good at lowering the transmission of HSV-2, making this combination ring potentially triple protective.
“The TFV/LNG ring may be the first device to become tested in women that will offer contraception in addition to HIV and herpes prevention,” said Dr. Clark. “And so far, tenofovir may be the only microbicide that\’s been proven to be effective in reducing HIV infections when used topically. It’s vital that you develop a number of delivery mechanisms for tenofovir to be able to serve different women’s needs.”
CONRAD’s product director David Friend Ph.D added, “Products only work when they\’re used. By having a ring that may remain in your body for approximately 3 months, our hope is this fact ring will offer you a strategy to increase adherence, and for that reason provide greater protection against HIV whilst preventing pregnancy.”
CONRAD’s deputy director of clinical research, Marianne Callahan, will also present information on MPTs later this week in the International Conference on Family Planning in Addis Ababa, Ethiopia. The CONRAD sponsored panel, “Development of Multipurpose Prevention Technologies (MPTs): Pathway from Product Development to the Customers,” will talk about the way the development of MPTs are associated with the regulatory approval process, the significance of acceptability research within target populations, and the need for going for a “systems approach” when it comes to feasibility of future introduction of the new technology.
In addition to the TFV/LNG intravaginal ring, CONRAD is testing the one-size-fits-most SILCS diaphragm with tenofovir gel. Used together, the diaphragm plus the gel can offer contraception as well as the possibility to reduce HIV and HSV-2 infections being an on-demand system providing immediate protection.
According to the World Health Organization, there are 35.3 million people coping with HIV around the world and approximately 87 million unintended pregnancies occur every year. Ms. Callahan says, “An unintended pregnancy is more tangible than a hidden virus so MPTs can lead to increased product use by offering an important mixture of protection that can have a major impact in developing countries.”
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