US NIH: preclinical research needs more female animals

Research is skewed towards using male animals and cells, obscuring sex differences that could be vital to clinical studies, NIH directors Janine Clayton and Francis Collins wrote in Nature​​.

After research is completed, publications often neglect sex-based analyses, they said, which could be a factor behind the “troubling​” rise of irreproducibility of preclinical research. Additionally, as women experience higher rates of adverse drug reactions to men, distorted preclinical work could be obscuring patient risks.

“Looking for differences between male and females is like a blind spot in biomedical research, so it isn’t often included in analyses, or published in journals,​” Clayton told this publication. “We want scientists to think about sex when designing studies.​”

Irreproducibility ​

“Inadequate inclusion of female cells and animals, and failure to specify sex used in experiments affects our ability to verify and duplicate results,​” Clayton told us. “We need researchers to specify their methods, including stating the sex of cells and animals used, and we want researchers to incorporate these considerations in experiment design, analysis, and reporting. ​

“And we need scientific journals to play a role by also asking for this to be included in methodology and to report sex-specific results and analyses.​”

While the new policy only applies to NIH-funded research, Clayton said the Institution’s leadership role could influence other researchers:

“We know that sex matters and NIH is taking action on multiple fronts. But we need all players to be a part of the solution. We all have a stake in the game. ​NIH is interested in building the strongest foundation of preclinical research results that are reviewed and used by the private sector in designing studies for specific therapeutics in women and men.​”

When we asked, NIH did not elaborate on what accommodations preclinical CROs (contract research organisations) would have to make to start performing more female research, such as extra training in experiment design, or running separate male and female experiments in tandem for the same drug candidate.

Clayton did tell us that the Institute is “developing policies to have applicants report cell and animal inclusion plans, and training modules to assist researchers in conducting their studies​” and advised we watch for announcements in October this year.