This is the definition adopted be both the National Institute for Health and Care Excellence ( and the European Association of Urology. 1 2

The degree to which men are affected is measured by the International Index of Erectile Function (IIEF) - a 15 -point patient questionnaire which was developed in conjunction with clinical trials for sildenafil.

Within IIEF, there are six specific questions (1 -5 and 15), known as the Erectile Function Domain (IIEF IIEF-EF Domain):

• How often do you get an erection?
• How often are erections hard enough to penetrate?
• How often are you able to penetrate?
• How often were you able to maintain erection after penetration?
• How difficult is it to maintain erection to complete intercourse?
• How do you rate your confidence to get and keep an erection?

These questions are used to classify whether a man is experiencing ED and, if so, how severe it is. Using this measure 3, a score of 26 -30 is classified as ‘no ED ’; 17 -25 is ‘mild ED ’; 11 -16 is ‘moderate ED’ and 6-10 signals ‘severe ED’. 4

In order to assess the efficacy of Eroxon ® Stimgel, and identify whether it was effective in men with varying degrees of ED the gold -standard IIEF Erectile Function domain (IIEF EF) , and two iterations of the more recently developed Sexual Encounter Profile (SEP2 and SEP3), were used in the FM57 trial. IIEF EF was used in the Eroxon ® Stimgel trial. 5

Response to an ED therapy is measured on the basis of achieving a minimal clinically important difference( which is defined as a meaningful change for the patient. 6