OXTR and premature ejaculation: However, in spite of the above preclinical studies, which support a role of spinal oxytocin in ejaculation, recent studies failed to demonstrate a meliorative effect of cligosiban, an orally administered oxytocin receptor antagonist being developed to treat premature ejaculation in men with lifelong premature ejaculation in a randomized, double-blind, placebo-controlled phase IIb trial [230] against the results of another randomized, double-blind, placebo-controlled proof-of-concept trial study [231].