The price of shares in German pharmaceutical group Schering fell by 10.13 percent in early trading Monday in response to a delay by the group in launching a colon cancer drug in the United States. The share prices fell to 52.63 euros ($69.38) after the company said that it would seek approval in the United States for the treatment, called PTK/ZK, at the beginning of 2007. Until now it had counted on obtaining approval this year. The company said that clinical trials, now in stage three of the development process, were not satisfactory. The announcement means that the launch of the treatment has been delayed until 2008 at the earliest. The company had expected to market the drug in 2006. Brokerage house equinet commented that even if the treatment were marketed in 2008, it might have difficulty in winning substantial market share because competing products would have gained a lead.