Reproductive toxicity testing of pharmaceutical compounds to support the inclusion of women in clinical trials.

1. The potential for toxicity to reproduction and the developing fetus is an important concern requiring attention during the development of new medicines. However, there are differences in the opinions of the regulatory authorities in Europe, Japan and the USA regarding the nature and amount of data from reproductive toxicity tests that should be available at the various stages of clinical development. 2. Forty-one companies or their subsidiaries from Europe, Japan and the USA provided data for a questionnaire-based study, carried out in 1994, to ascertain the practices of pharmaceutical companies and their views on an ideal approach to the timing of reproduction and development toxicity studies in relation to clinical investigation. 3. Differences were identified in the stage of drug development at which animal studies were completed, the sequence of completion of specific studies, and the extent of reproduction testing completed to support the inclusion of women in clinical trials. 4. A harmonised, but flexible, guidelines, encompassing the timing of reproductive toxicity studies in relation to clinical trials, would permit better integration between clinical and non-clinical studies in an international drug development programme.