JAMA: A high-dose treatment of sodium nitrite, 6 percent, with citric acid,
9 percent, creams applied twice daily was more effective than placebo
for treating the common sexually transmitted disease of anogenital
warts, according to an article published online by JAMA Dermatology.
The warts are caused by infection with human papillomavirus (HPV)
types 6 and 11 in more than 90 percent of cases. Topical therapies and
surgical removal of the warts are associated with local adverse
reactions that include itching, burning, pain and erosions. Recurrence
with existing therapies is about 30 percent, according to the study
background.
Anthony D. Ormerod, M.D., of the University of Aberdeen, Scotland,
and coauthors looked at the efficacy of a topical application of nitric
oxide delivered using acidified nitrite in a clinical trial conducted in
European genitourinary medicine clinics.
The four-arm trial included 299 individuals from 40 centers who were
assigned to either placebo or three acidified nitrite intervention arms
which ranged in dose. The doses were: sodium nitrite, 3 percent, with
citric acid, 4.5 percent, creams applied twice daily (low dose); sodium
nitrite, 6 percent, with citric acid, 9 percent, creams applied once
daily at night with placebo in the morning (middle dose); and sodium
nitrite, 6 percent, with citric acid, 9 percent, creams applied twice
daily (high dose). The sodium nitrite cream was applied first and then
the citric acid because citric acid reacts with nitrite to form the
active molecule when mixed (NO, nitric oxide). Participants in the
placebo arm applied sodium nitrite placebo with citric acid placebo
twice daily.
The study found complete clinical clearance at 12 weeks in 10 of 74
(14 percent) patients with placebo; 11 of 72 (15 percent) with low-dose
treatment; 17 of 74 (23 percent) with middle-dose treatment; and 22 of
70 (31 percent) with high-dose treatment.
The authors note a dose-related increase in itching, pain, edema
(swelling) and staining of the anogenital skin that was associated with
active treatment.
“Sodium nitrite, 6 percent, with citric acid, 9 percent, twice daily
is more effective than placebo in the treatment of anogenital warts.
Treatment in the present study was associated with local irritant
adverse effects. Lower doses were not more efficacious than placebo. For
the sensitive anogenital application site, this dose probably
represents the optimal one for further evaluation,” the study concludes.
(JAMA Dermatology. Published online April 29, 2015. doi:10.1001/jamadermatol.2014.0381. Available pre-embargo to the media at http://media.jamanetwork.com.)
Editor’s Note: Authors made conflict of interest disclosures.
The study was funded by ProStrakan and support was provided by Origin
Pharmaceuticals. Please see the article for additional information,
including other authors, author contributions and affiliations,
financial disclosures, funding and support, etc.