New Inhaled Impotence Drug Shows Promise
Backers Say PT-141 Is Effective and Safe
GI Problems Seen at Higher Doses
The men in the PT-141 trial who took the highest doses of the drug did have an unacceptably high incidence of gastrointestinal side effects, including nausea. They made up almost all of the roughly 12% of patients who dropped out of the trial, and one researcher says future studies will not include these higher doses.
Those included in the trial had mild to severe erectile dysfunction, and all had taken Viagra prior to enrollment and had responded well to it. The men took PT-141 via nose sprays at least three times, and some took it as many as 10 times before reporting improved erections.
One in 10 men who received placebo treatments reported restoration of normal erectile function, compared with roughly one in three patients treated with the lowest dosage of PT-141 and one in two patients treated with the highest dosage.
Palatin Technologies CEO Carl Spana, PhD, said men taking part in future studies will be started off at the lowest dosage and dosages will be increased gradually, if needed, to minimize side effects.
The company is also planning drug interaction studies evaluating the safety of PT-141 in men using nitrate medications for heart disease. Viagra and similar drugs are not recommended for these patients, and Spana says they account for roughly 10% of men with erectile dysfunction.
"We have no reason to expect that PT-141 will interact with nitrates," he says. "This represents a significant potential advantage."
San Francisco urologist Ira Sharlip, MD, who researches new impotence treatments but was not involved with the PT-141 study, tells WebMD that it is too soon to know whether the new drug will end up being an important new treatment.
"Right now in the United States we have Viagra and Levitra, and I expect that Cialis will soon be available," he says. "These are good drugs, but they aren't perfect. They don't work for everybody, so having a drug that works by a completely different mechanism of action is an attractive prospect."