Not enough women are being included in European clinical drug trials, despite the acknowledged gender differences in the effectiveness of treatments, say public health researchers in the Journal of Epidemiology and Community Health.

The European Medicines Agency (EMEA), the body responsible for licensing drugs and approving drug trials in Europe, has failed to develop any gender specific guidelines or strategies, they say.

Although the agency acknowledges potential sex differences in the actions of drugs, it has argued against providing separate guidelines, but without providing the evidence on which this decision is based, say the authors. “The lack of sound fundaments of these convictions is worrisome,” they say.

It is unusual for clinical trial reports to include “the minimum gender information,” they write.

For example, too few women have been included in HIV drug trials to allow for sufficient analysis of the gender difference and its potential impact. Only one of the 117 trials in the register for the period 1990 to 2002 included any gender analysis.

And the proportions of women included do not reflect the proportions who are HIV positive, they say.

Europe needs to take its lead from the USA, where the law requires sufficient numbers of women, including those of childbearing age, to be included in clinical trials, and for gender differences in drug reactions and effectiveness to be evaluated, they say.

The EMEA accepts that women’s participation in trials in their early stages, where safety, dosing, and side effects are determined, is lower than is preferable, but “the agency does not consider this inadequate representation to be relevant,” write the authors.

“…when women are excluded, any specific dosing requirements for them will remain undiscovered until much later in the drug development process, if ever,” they continue.

The authors contend that the expense of mounting large research trials is likely to put the squeeze on bumping up the numbers of women in trials. But they say that the EMEA should use its muscle to ensure that sufficient work is done to protect the women who will eventually be using those drugs.