Condom ceases to be the only common method of HIV prevention. As far as ‘dream’ about anti-HIV vaccination is out of range of modern medicine, scientists are looking for new kinds of pre-exposure prophylaxis. A new development of this group is intravaginal ring containing experimental drug – Dapivirine, which is supposed to prevent viral infection. Currently, a large trial is running in five African countries in order to test effectiveness an extended safety of this contraceptive. Results are expected in early 2015.
In Africa, as quoted by WHO (2008), 50 percent of HIV-infected adults are women. They are the main group for whom the new contraceptive is designed. It is supposed to be discreet and, in contrast to condoms, independent of sexual partner option of contraception and HIV prevention for women. National Institutes of Health, which are funding the trial, indicates relatively prolonged protection from infection and ease of using as the main strong points of this contraceptive.
Intravaginal ring used in tests is made out of silicone and contains experimental antiretroviral drug- Dapivirine. The drug is continuously released in vagina during four weeks, hence every month the ring has to be replaced by new one.
Dapivirine was registered in 2004 as a NNRTI drug. It prevents HIV-1 from replicating its genetic material after the virus enters a healthy cell. Also partial effectiveness considering HIV-2 was noticed. One-use dose in ring is 25 mg. Substance was tested several times to show lack of teratogenic, mutagenic activity and very rare adverse effects. The strongest point of the drug was effectiveness of transvaginal application – tests in vivo showed 70 to 100 percent of effectiveness, depending on the group. Additionally, low cost of production is one of the most important reason to use Dapivirine in this research. In conducted trial 60 percent of effectiveness of substance using in intravaginal ring is expected.
Research ‘A Study to Prevention Infection with a Ring for Extended Use’ (ASPIRE) enrolls about 3500 women in age 18-45 from five African countries- Malawi, South Africa, Uganda, Zambia and Zimbabwe. Half of the participants is given contraceptive with Dapivirine, while rest of them use placebo. During twelve-month-project women are under obligation to make a control visit every 4 weeks. Then they will be tested for pregnancy and HIV, receive condoms and counseling on how to reduce their risk of becoming infected with HIV and other sexually transmitted pathogens. Those of women who become infected with virus during study will be immediately subjected to professional medical care.
It is worth saying that holding research are the next try of American scientists who are looking for effective methods of HIV-infection prevention. Previous projects involved microbiocide gel containing AVR-drugs. Results of the most current research – The VOICE study (November 2011), in which as a antiviral drug was Tenofovir, indicated lack of increased effectiveness of this meth in comparison to placebo. Hopefully, this time the results of studies will be more optimistic. We are looking forward to their publication in the first quarter of 2015.
Written by: Monika Walankiewicz
Source:
1. http://www.nih.gov/news/health/jul2012/niaid-24.htm
2. http://www.ncbi.nlm.nih.gov/pubmed/18681822
3. http://www.ipmglobal.org/our-work/ipm-product-pipeline/dapivirine-tmc120
4. http://www.aidsmeds.com/articles/hiv_microbicide_ring_1667_22823.shtml
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New option of HIV prevention?
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