Bayer has linked up with fellow German firm Evotec AG have entered into a five-year collaboration to develop drugs for endometriosis.

The firms say they are hoping to develop three clinical candidates for the disease, a frequent and painful condition in which endometrial cells grow outside of the uterine cavity. Cashwise, Evotec may receive milestones of up to 580 million euros, plus up to low double-digit royalties, "depending on which party brought the compound to the collaboration".

Evotec chief executive Werner Lanthaler said that because endometriosis affects women in childbearing age, "there is an incredible need for new, non-surgical treatments that will preserve fertility and alleviate pain". Andreas Busch, head of global drug discovery, noted the importance of women's health to the firm's business, adding that this is one of the company's "strategic research indications".

Endometriosis affects 176 million women worldwide or 10% of women of reproductive age. There is no known cure and "most available drug treatments have certain limitations", Bayer said.