Patients suffering from erectile dysfunction prefer rival drugs over the pioneering treatment, Pfizer’s Viagra, two studies to be presented at a meeting of sexual medicine researchers showed.
Cialis, a drug marketed by Lilly-ICOS, a joint venture between Eli Lilly and ICOS Corp., emerged as the top option in one trial, and Levitra, sold by Bayer and GlaxoSmithKline led its rivals in the other.
The studies are to be presented at the sixth congress of the European Society for Sexual Medicine in Istanbul on Monday.
The results are likely to give the companies ammunition in their fierce battle for market share with Pfizer’s Viagra, the first drug of its kind on the market that revolutionized the treatment of erectile dysfunction, or impotence.
Excerpts from a study of 150 patients carried out by Hamburg urologist Hartmut Porst showed that 45 percent of patients preferred Cialis, 30 percent Levitra and 13 percent Viagra.
Twelve percent had no preference.
“The overwhelming majority of the patients prefer the two new drugs with tadalafil being ahead due to its long duration of action,” the study said.
Tadalafil is the name of the active chemical in Cialis.
Another study, led by Frank Sommer at the University Medical Centre in Cologne, showed that 43 percent of men in a high dose, three-way preference trial preferred Levitra.
Forty percent of the patients preferred Cialis and 17 percent preferred Viagra.
Levitra was also found to be the preferred option at a lower, initial dose, with Viagra second and Cialis third.
Currently 86 men have completed the maximum dose trial and 47 the lower dose trial.
Viagra, Levitra and Cialis all work by blocking an enzyme called PDE-5, which affects blood flow and is important in treating erectile dysfunction.
Their relative merits with respect to speed of action and duration of effect are disputed, but analysts say the two new drugs have widened the market for anti-impotence treatments.