Germany's Schering AG has started three Phase II studies in Europe of a new drug to treat solid tumours, including non-small cell lung, ovarian and breast cancers.

The epothilone drug, called ZK-EPO, is the only fully synthetic drug in this class in clinical development, accoridng to Schering. Epothilones are a novel class of cytotoxic agents that are said to have the potential to replace the widely used taxane class of chemotherapeutics.

Schering said ZK-EPO is designed to improve efficacy and safety compared to the chemotherapies currently available.

A German study is looking at the efficacy and safety of ZK-EPO as second-line therapy in patients with advanced NSCLC, while a UK study is assessing its effects in recurrent ovarian cancer and a metastatic breast cancer trial is enrolling patients at 24 medical centres in European countries, including France and Austria.

“The Phase I data leads us to believe ZK-EPO has potential to become an important new anticancer therapy to treat people with a variety of solid tumors," said Carlo Montagner, head of oncology at Schering. The company is anticipating ZK-EPO could reach the market in 2010 or later.

Although still in early-stage development, ZK-EPO has assumed greater importance for Schering after a series of product setbacks at the German company.

Last week the US Food and Drug Administration (FDA) declined to approve its vascular imaging agent Vasovist (gadofosveset trisodium), and last month Schering said that it would stop giving its uterine fibroid drug asoprisnil to patients in trials after seeing endometrial changes in some individuals.

Then in September, a trial of leukaemia drug Campath (alemtuzumab) in multiple sclerosis was halted after a patient died of a rare blood disorder, although the drug showed remarkable efficacy.

And in the summer Schering and Novartis said they were reviewing plans for cancer drug PTK/ZK after the drug failed to extend survival in a trial involving patients with advanced colorectal cancer. Finally, in May Berlex Laboratories, the US affiliate of Schering, said it was facing a significant delay in bringing its bone metastasis agent Bonefos (clodronate) to market in the USA.