SUD-003 : erectile dysfunction

SUD-003 (DuroMist™) is a first-in-class oral spray formulation of sildenafil (marketed in tablet form by Pfizer under the brand name Viagra®), sprayed directly in the mouth over the tongue for the treatment of erectile dysfunction (ED). The Duromist™ dosage form is a metered spray that offers the potential for increased patient convenience, reduced food effect and lower dose.

Sildenafil is the largest selling drug globally for ED and is also approved to treat pulmonary arterial hypertension (see SUD-004). Sildenafil acts by inhibiting phosphodiesterase type 5 (PDE5), an enzyme that promotes degradation of cyclic guanosine monophosphate (cGMP), which regulates blood flow in the penis.

DuroMist™ has been evaluated in a pilot pharmacokinetic (PK) clinical trial comparing the lingual spray to oral sildenafil (Viagra®). The trial was designed to assess the relative bioavailability and safety of one, two and three sprays of 10mg/0.12ml of DuroMist™, compared to a 25mg Viagra® tablet. It was a single-centre, open-label, single-dose, randomised, four-period, four-treatment, crossover study under fasting conditions. There were 24 healthy adult male subjects enrolled in the study.

The results from the trial successfully demonstrated that the 20mg dose (two sprays) of DuroMist™ was bioequivalent to the 25mg Viagra® tablet with respect to systemic exposure. The mean systemic exposure with the 10mg dose (one spray) was approximately 40% of the 25mg Viagra tablet, as expected; and the 30mg dose (three sprays) was approximately 40% higher than the 25mg Viagra® tablet, which was about 20% higher than expected.

These data suggest that DuroMist™, as compared to the Viagra® tablet, provides effective absorption of sildenafil via the oral transmucosal route. Furthermore, DuroMist™ demonstrated an excellent safety profile and was well tolerated in the PK study at all dose levels.

The US FDA accepted an Investigational New Drug (IND) application following a successful pre-IND meeting to discuss the clinical plan for registration. In 2014, SUDA commenced formulation work on a second-generation version of DuroMist™, which has vanilla and peppermint flavouring, together with absorption enhancers to quicken the onset of action. Stability studies on the new formulation are underway, prior to further dialogue with the FDA.

Treatment of erectile dysfunction was a multi-billion dollar global market in 2012. In the USA alone, more than 18 million individuals suffer from ED. The risk of developing ED increases with age. Primary market research conducted in the USA suggests that over two thirds of physicians would prescribe DuroMist™ to their patients if the oral spray achieved a quicker onset of action or reduced the side-effects associated with Viagra®.

If you are interested to learn more about DuroMist™ please email This email address is being protected from spambots. You need JavaScript enabled to view it. (Chief Business Officer).