Benzoyl Peroxide Not Linked To Tumors In Rats, Mice, CHPA Studies Find
This article was originally published in The Rose Sheet
Executive Summary
Two-year dermal carcinogenicity studies found "no evidence of oncogenicity resulting from daily topical application" of benzoyl peroxide gel on rats and mice, the Consumer Healthcare Products Association says
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Two-year dermal carcinogenicity studies found "no evidence of oncogenicity resulting from daily topical application" of benzoyl peroxide gel on rats and mice, the Consumer Healthcare Products Association says. In both F344 rats and B6C3F1 mice, benzoyl peroxide gel had no effect on survival, body weights or food consumption, and produced no evidence of systemic toxicity. In addition, microscopic evaluation revealed "treatment-related findings confined to the site of application," CHPA says in a Dec. 27 letter submitted to FDA on behalf of the association's Benzoyl Peroxide Study Group. Rats were administered daily topical doses of benzoyl peroxide carbopol gel up to 45 mg for 104 weeks. Mice initially were administered up to 25 mg per day, although the high dose caused treatment-site ulceration, thereby exceeding the maximum tolerated dose (MTD), and was lowered to 15 mg/day at week 57. Because ulceration also occurred in mice receiving 15 mg/day, high-dose treatment was suspended and the vehicle was administered from week 93 until the end of the study with FDA's approval, CHPA says. Specific findings in mice were "dose-dependent induction of acanthosis, hyperkeratosis, sebaceous gland hyperplasia and subepidermal inflammation," CHPA says. "Ulceration...was consistent with the conclusion that the high dose exceeded the MTD." The studies demonstrate benzoyl peroxide "lacks carcinogenic potential," CHPA maintains. "The absence of any skin tumors in F344 rats and B6C3F1 mice is particularly important considering the induction of chronic hyperplasia and other skin effects indicative of reaching" the MTD. CHPA submitted interim, one-year data from the rat and mouse studies, in addition to a 12-month photocarcinogenicity study and various investigative studies, in March 1999. The submissions respond to FDA's August 1991 decision to reclassify the topical acne product from Category I (safe and effective) to Category III (available data insufficient). "Given the clinical and experimental data from humans and animals, benzoyl peroxide acne treatment products warrant no additional labeling warning against theoretical or rodent tumor promotion or phototoxicological concerns," CHPA maintains. |