Schering AG lost value on Berlin’s stock exchange this morning as the company said it would stop dosing patients with its investigational drug, asoprisnil, for uterine fibroids after seeing endometrial changes in some participants.

Following Phase III trials, patients could elect to be included in extension studies that would extend their total time on therapy for up to four years. Although the endometrial changes observed were reversible in “most patients,” they did result in additional invasive procedures, leading the company to amend the extended investigation and to discontinue dosing. Patient will be followed up as part of these extension studies.

But both Schering and North American partner TAP Pharmaceuticals continue to believe in the benefits of asoprisnil and say they will discuss submission plans with drug regulators in the USA and Europe. Schering has previously highlighted asoprisnil as part of its drive towards improving profitability [[26/04/05a]].