Schering Defends Cyproterone Products

Schering AG of Germany has defended its two cyproterone acetate-based products, Diane-35 and Androcur, saying that there is no evidence that either product causes cancer (Marketletter August 22). The company added that more than 15 million people have used the compound since it came onto the market in the 1970s.

The German Federal Institute for Drugs and Medical Devices has begun an investigation into the alleged tumorigenic effects of the drug, which has emerged from in vitro studies carried out by German and Italian researchers. Schering claims that it has been aware of the supposed link for some time and has carried out numerous studies to test it. While some cases of cell proliferation of liver cells in culture had been observed, the cells were not neoplastic and there was no evidence that they would necessarily become so, said the company. In any event, the occurrence of these changes was so rare that it is unlikely that the risks would outweigh the benefits of the drug.

The German and Italian researchers say that while Schering has tested for proliferative effects of cyproterone, its studies have not looked at whether the drug interacts with the cells' DNA. They note that they have found that cyproterone interacts with DNA in cultured rat and human liver cells, which could pose a risk of mutations when the cells divide.