NEW YORK (Reuters Health) – Rates of clearance of high-grade anal canal intraepithelial neoplasia in men with HIV are improved considerably by topical application of imiquimod cream, a UK team reports in an August 19 online issue of AIDS.
Dr. Paul A. Fox with the Chelsea and Westminster Hospital NHS Trust, London, and colleagues note that anal cancer is a growing problem in HIV-positive men, making it urgent to define optimum treatment for pre-cancerous anal intraepithelial neoplasia (AIN).
The researchers tested the effects of 4 months of treatment with imiquimod cream versus placebo applied into the anal canal in 53 patients with HIV and high-grade AIN. All were on HAART for at least 3 months and had a CD4 cell count of at least 100.
Because imiquimod can be absorbed systemically and cause side effects if applied too high in the anus, the patients “were instructed on how to self-apply the cream three times a week by inserting a finger no further than 2 cm into the anal canal.”
Among the 28 patients on active drug, AIN either resolved or downgraded in 12. Among the 25 patients given placebo, 1 patient resolved. “Imiquimod was significantly associated with a positive outcome (p=0.003),” the team found.
That blinded trial was followed by an open-label phase of treatment for a further 4 months, entered by 21 patients who had not had a clearance of AIN. The condition resolved or downgraded in 9 of them.
“The total number of patients who have exhibited prolonged absence of HSIL (high grade squamous intraepithelial lesions) following treatment with imiquimod is 29 out of 47 patients (61%),” Dr. Fox and colleagues report.
They conclude with a call for more screening for AIN in all HIV-positive patients, now that the efficacy of intra-anal topical imiquimod has been demonstrated. “This is certainly not going to prevent all anal cancers, but it would be a grave error to await the outcome of long-term natural history studies. Although much more research is needed, the time has come for all HIV centres to begin screening for and treating AIN.”
