Shares in ProStrakan, the Borders-based speciality pharmaceutical group, plunged almost 5% yesterday after it emerged US health regulators delayed approval of its cure-all for the male menopause. The company, which has its headquarters in Galashiels, yesterday said its US partner Endo Pharmaceuticals had “received a complete response letter from the US Food and Drug Administration” in relation to Fortesta, known as Tostran in Europe. ProStrakan shares yesterday fell 4.9%, or 6.25p, to 121p. However, Endo, which bought the US licensing and distribution rights for the product from ProStrakan for up to $50m, said it expects to file a “complete response” by mid-2010. The product is a testosterone replacement gel for 40-plus males with a condition known as hypogonadism, the symptoms include baldness, weight gain, lethargy, irritability, reduced libido and erectile dysfunction. Wilson Totten, the chief executive of ProStrakan, said: “We remain confident that we will be able to reassure the FDA that Fortesta should be approved.” The US testosterone market in 2007 was worth £660m. An estimated 13.8 million American men are estimated to have testosterone levels characterised as below normal, the company said. Totten also commented: “Male hypogonadism remains a problem for many men and our experience across Europe, where this product is already on the market, shows that Fortesta has a role to play in tackling this condition.” CONFIDENT: Wilson Totten thinks Fortesta will be backed.