The gender gap in HIV clinical research

Although it seems hard to believe today, prior to 1993, women of childbearing age were often excluded from clinical trials due to concerns of exposing unborn fetuses to experimental drugs. Many HIV positive women were thus not eligible to enter clinical trials for new therapies at a time when there were very few drugs available.  The data defining HIV treatment efficacy and safety came primarily from trials on men. 

This all changed in 1993 when the FDA made participation of women mandatory in clinical trials and required studies to include gender specific analysis of efficacy and safety. Following this, the NIH started the largest and longest running study to investigate the impact of HIV on women: women’s interagency HIV study (WIHS). Advances were made in understanding the specifics of HIV during pregnancy, as well as interactions with contraception, gynecological pathologies and menopause. Today, 20 years later, women comprise 12-23% of participants in HIV clinical trials and up to 37% in more recent key studies defining treatment regimens or new antiretroviral (ARV) drugs.

However, despite enormous progress in narrowing the gender gap, clinical guidelines still contain little gender-specific references for ARV treatment, adherence, toxicity or long term effects. This is about to change. Last month, HIV specialists and health professionals in Spain drafted a document calling for a differentiated approach to HIV clinical management in men and women. This document has been promoted by the Grupo de Estudios de Sida (Gesida) de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica (Seimc) y la Secretaría del Plan Nacional sobre el Sida.

What does this document mean?  It means for example that if CD4 T cell counts are intrinsically different between men and women and vary by stage of life, recommendations on when to start ARV may need to be fine-tuned.  Or, if metabolism and lipid redistribution are different in women and men, ARV toxicity could vary by gender and thus needs to be taken into account. This type of thinking will ensure that clinical management of HIV is no longer simply extrapolated from men to women. According to the document, HIV clinical research and guidelines should take into account biological, psychological and social differences between men and women. HIV specialists support that the need for gender-specific clinical recommendations is urgent in a world where nearly half of the world’s individuals living with HIV are female.