GlaxoSmithKline has licensed co-development rights to a topical formulation of the widely-used angina drug glyceryl trinitrate that could become the first over-the-counter product to treat erectile dysfunction.

If it proves successful in clinical trials, the gel product, developed by UK firm Futura Medical, could provide an alternative therapy for men who do not respond to treatment with oral phosphodiesterase 5 inhibitors such as Pfizer’s Viagra (sildenafil). It could also shift some of the cost of managing ED from national health systems to patients’ own pockets and, given that just 15% of men with ED seek prescription treatment, could actually increase treatment rates.

The local action of the product could also be an advantage as it avoids systemic exposure to medication, unlike the PE 5 inhibitors, said Futura. And glyceryl trinitrate, which is already available OTC for angina, has its own built-in safety valve to guard against over-dosing: apply too much and the first symptom to develop is a severe headache.

GSK has committed funding of around £2.4 million to the project, which will pay for the lion’s share of Futura’s clinical trial programme for MED2002, expected to cost around £3.65 million. The trials will enroll around 1,500 men and are scheduled for completion in time for regulatory filings for the product in 2008.

Under the terms of the agreement, GSK has global distribution and marketing rights for MED2002. In return, Futura receives a royalty on all MED2002 sales for the lifetime of the MED2002 patents, currently expected to run until around 2024. GSK also gets first refusal rights for two other OTC products in early-stage development at Futura, including a treatment for arousal and desire disorders associated with female sexual dysfunction and a non-prescription treatment for premature ejaculation.