Early Clinical Results Show Pre-Exposure Prophylaxis Products Prevent HIV, But Methods Lack Worldwide Adoption

As pre-exposure prophylaxis (PrEP) remains at the forefront of HIV prevention research, clinical trial investigators provided an update on recent oral and topical PrEP efficacy studies at the second plenary session of the 7th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2013), held June 30 to July 3 in Kuala Lumpur, Malaysia.

Javier R. Lama, director of HIV prevention interventions studies in the clinical trials unit of the Asociación Civil Impacta Salud y Educación in Peru, said recent studies proved the efficacy of vaginally applied and daily oral tenofovir-based antiretroviral PrEP in preventing HIV-1 infection in various at-risk populations. However, Lama noted other PrEP clinical trials failed to show efficacy, which has resulted in numerous questions about PrEP’s applicability in diverse groups, optimal dosing, delivery method, and adherence promotion and monitoring. For example, “it is still unknown which PrEP strategies such as oral or rectal, if efficacious, would work best to prevent HIV infection in populations at risk via unprotected receptive anal intercourse, as well as to whom each strategy would be targeted and the specifics of usage,” Lama said in a news release from IAS and the Malaysia-based Centre of Excellence for Research in AIDS (CERiA).

To address those queries, Lama said follow-up studies are currently being conducted or planned. In case those trials deem oral and topical antiretroviral PrEP effective and the products get launched commercially, Lama considered issues that could potentially arise in the near future surrounding the translation of those updated clinical findings into public health policies to prevent HIV infection in at-risk populations.

“Regulatory approvals and guidelines for PrEP vary widely, and policymakers — with advocacy from populations at risk — are considering the implications of translating positive PrEP findings into programmatic priorities,” Lama said in the press release. “In addition to advocacy from populations at risk and governmental support of public health rollout, two key aspects of a successful prevention program include a high-risk population willing to use such a method and providers willing to deliver it.”

Barbara de Zalduondo, senior advisor to the deputy executive director for program of UNAIDS, the Joint United Nations Program on HIV/AIDS, said socio-cultural, economic, and political barriers that include stigma and punitive laws play a significant role in the insufficient coverage of rights-based and evidence-informed HIV prevention services. Though Zalduondo acknowledged 15 structural intervention approaches are available to support those programs, she noted there’s still a lack of investment to appropriately evaluate and implement those methods to provide more effective HIV responses through PrEP and other clinically supported techniques.

“At a time when groups such as men who have sex with men and female sex workers are bearing the brunt of the (HIV) epidemic in South East Asia, new prevention tools are needed to ensure these vulnerable groups are protected,” IAS 2013 International Chair and International AIDS Society President Françoise Barré-Sinoussi said in the news release. IAS 2013 Local Co-Chair and CERiA Director Adeeba Kamarulzaman added “those governments who are not basing their policies on scientific evidence are facing a stark choice — either accept the harm-reduction evidence to bring down HIV infections, or ignore it at a huge economic and human cost.”