Too few women are enrolled in drug clinical trials in Europe, and those who do take part are unprotected because of European Medicines Agency (EMEA) policy, Spanish public health researchers have claimed.
While the EMEA has agreed that certain factors which influence a drug’s effect “may be important when considering potential differences in response between men and women” and that “gender-specific influences” can have significant roles in drug effects, it does not believe that separate guidelines are needed for women, say researchers Maria Teresa Ruiz Cantero and Maria Angeles Pardo, who add that it is “worrisome” that the agency has not provided evidence for this decision.
Moreover, the EMEA is aware that fewer women participate in the early stages of clinical trials - when the new drug’s safety, side effects and safe dosage range are determined - but it does not consider this inadequate representation to be relevant, the researchers add. However, “when women are excluded, any specific dosing requirements for them will remain undiscovered until much later in the drug development process, if ever,” they warn.
For example, just 14.43% of adults taking part in a total of 117 trials for HIV treatments during 1990-2002 were female, even though the percentage of women living with HIV/AIDS in western Europe in 2002 was 25%, and 49% worldwide.
And, while 74% of people taking part in the clinical trials done with Merck & Co’s arthritis drug Vioxx were women, 80% of the trials did not describe efficacy results by sex - just one reported side effects by sex. 60% and 88.9% of the trials, respectively, did not specify the influence of oral contraceptives or oestrogen treatments, and just 50% considered pregnancy as an exclusion criterion.
The study calls on Europe to follow the example of the USA, where the inclusion of women in clinical research was recommended as far back as 1986. Obstacles to getting more women into trials include costs but, to avoid future problems, the EMEA needs to use its regulatory clout to ensure that drugs are safe and effective for the women who will eventually use them, the researchers conclude.
This paper is published in the Journal of Epidemiology and Community Health (2006: 60: 911-13).