The efficacy of CAVERJECT IMPULSE was based upon clinical studies of CAVERJECT.

The efficacy of CAVERJECT was investigated in men with a diagnosis of erectile dysfunction due to psychogenic, vasculogenic, neurogenic, and/or mixed etiology in two double-blind placebo-controlled studies (Study 1 and Study 2) and in one 6-month open-label study (Study 3). In clinical studies (Study 1 and Study 3), over 80% of patients experienced an erection sufficient for sexual intercourse after intracavernosal injection of CAVERJECT.

Study 1: A total of 153 men with ED with a mean age of 53 years (range 23–69 years) were enrolled. The study had three phases: a 2.5 week, randomized, double-blind, placebo-controlled crossover phase in which each man received in-office injections of placebo or 2.5 mcg, 5 mcg, 7.5 mcg, or 10 mcg of CAVERJECT; a 2 week, open-label, in-office dose-titration phase to identify the optimum home-use dose (the latter dose was defined as a dose inducing an erection sufficient for intercourse and lasting ≤ 60 minutes); and a 4-week open-label, at-home phase. In the double-blind placebo-controlled, crossover phase, each dose of CAVERJECT was significantly more effective than placebo by clinical evaluation ("full penile rigidity") and by RigiScan criteria (≥ 70% rigidity for at least 10 minutes); there was no response to placebo. The percentage of responders increased with increasing doses of CAVERJECT. The overall response rates in the crossover and dose-titration phases were 76% (117/153) by clinical evaluation and 51% (78/152) by RigiScan criteria. Seventy-three percent of the injections in 102 men who used CAVERJECT in the at-home phase resulted in satisfactory intercourse. Seventy-five percent of the men who used CAVERJECT in the at-home phase remained on the dose identified as optimum for them during the dose-titration phase; 17% and 8% of the men decreased or increased their dose, respectively. The mean duration of erection per injection was 70.8 minutes.

Study 2: A total of 296 men with ED with a mean age of 54 years (range 21–74 years) were enrolled in this double-blind, placebo controlled, parallel-arm design study. The men were randomly assigned to one of five groups and received either a single dose of placebo, 2.5 mcg, 5 mcg, 10 mcg, or 20 mcg of CAVERJECT. No patient responded to placebo. The differences in the response rates in both the clinical and the RigiScan evaluations between each of the doses of CAVERJECT and placebo were statistically significant. There was also a statistically significant dose-response relationship with higher clinical response rates and higher RigiScan response rates with increasing doses of CAVERJECT (with exception of the 10-mcg dose). The mean duration of erection after injection ranged from 12 minutes after the 2.5-mcg dose to 44 minutes after the 20-mcg dose and the relationship was linear (p = .025, linear regression analysis).

Study 3: The efficacy of CAVERJECT was further evaluated in a 6-month, open-label, at-home study in 683 men with ED with a mean age of 58 years (range 20–79 years). The optimum dose of CAVERJECT was established by titration in 89% of men (606/683). A total of 471/683 men (69%) completed the 6-month study. Eighty-seven percent of the 13,762 injections of CAVERJECT administered resulted in satisfactory sexual activity. The mean duration of erection was 67.5 minutes.

The formulation of alprostadil contained in CAVERJECT IMPULSE was compared to CAVERJECT in 87 men with ED in a single-blind, crossover study. The doses used by the patients in the study ranged from 2.5 mcg to 20 mcg and were the same for both formulations. The efficacy of the two formulations was shown to be comparable, as assessed by the 30-point erectile function (EF) domain score from the International Index of Erectile Function (IIEF) and by a physician-assessment score for erectile response. The mean EF domain scores for CAVERJECT and CAVERJECT IMPULSE were 26.6 (SD=5.3) and 27.6 (SD=3.8), respectively. The mean physician's assessment scores for CAVERJECT and CAVERJECT IMPULSE were 2.6 (SD=0.6) and 2.7 (SD=0.5), respectively, based on a scale of 0 (no tumescence) to 3 (full rigidity).