乌鸦传媒

ORLANDO -- An investigational nitric oxide-releasing topical gel appeared to be safe and effective for the treatment of genital or perianal warts, researchers said here.

Complete clearance of baseline warts in the intention-to-treat analysis was achieved in 33.3% of 30 patients treated with topical application of the high dose of the agent (12% SB206) compared with 4.3% of 27 patients who used a vehicle gel (P=0.0099), according to of the University of Texas Health Science Center in Houston, and colleagues.

Complete clearance of baseline warts in the per protocol analysis was achieved in 42.1% of patients treated with the high dose of 12% SB206 compared with 6.7% of patients who used a vehicle gel (P=0.02), he reported in a presentation at the American Academy of Dermatology (AAD) annual meeting.

In the dose-ranging phase II trial conducted at 15 U.S. centers, researchers found that the twice daily dosing of SB206 was too toxic and was discontinued after recruiting 12 patients for that dose. In the intention-to-treat analysis, a 4% gel dose of SB206 reduced warts 20.8% among the 23 patients who received that dose, but that difference from the vehicle gel was not significant.

Tyring said 14.3% of the 14 patients who received the 8% gel dose of SB206 were free of warts by week 12 of the trial, but that difference also was not significant when compared with the vehicle gel.

AAD session moderator, of Oregon Medical Research Center in Portland, called the results "compelling. This is a novel mechanism of action. I think that nitric oxide has promise for a number of dermatologic conditions."

Tyring explained that the experimental agent contains NVN1000, a macromolecule that raises nitric oxide, which is an endogenous anti-viral agent. In preclinical trials, the use of SB206 inhibited formation of warts in animal models.

About 70% of the 108 study participants were men, and were in their 30s. Eligible patients had two to 20 external genital/perianal warts at baseline.

Of the 12 patients given the twice daily formula, 35% quit the study due to adverse events.

The researchers also analyzed treatment by sex. Tyring said that among the patients treated with once daily doses of SB206, 25% of males and 23% of females achieved complete clearance of baseline warts. About 6% of men, but no women achieved complete clearance of warts when they were treated with vehicle gel.

Overall, in the per protocol population of patients who received once daily SB206, there was a 60% reduction in baseline wart counts compared with about a 32% decline for patients who were given the vehicle gel at week 12.

In considering just the 12% formulation of SB206, Tyring reported that use of the gel was associated with a decline of both baseline and recurrent warts when compared with the vehicle gel at week 12 (P<0.05). In addition, the higher dose appeared to be safe with a 16.7% rate of application site adverse events and a low 3% rate of discontinuation.