Zileuton disappoints for acne relief, rosacea hopes dashed also ?

Written by David Pascoe on August 4, 2005 in Acne Treatments with 1 Comment

Zileuton has been hyped and hoped as the first real breakthrough drug to treat rosacea in over a decade.

Zyflo (Zileuton) was approved by the U.S. Food and Drug Administration (FDA) in 1996 for the treatment of asthma in patients 12 and older.

Recent clinical trials have tried to measure its effectiveness in treating acne. The rosacea hope was that Zileuton’s affect on inflammatory papules and pustules could be enjoyed by rosacea sufferers. Also some reduction in sebum production seemed hopeful for those suffering with rosacea and acne together.

Zileuton works by blocking the 5-Lipoxygenase (5-LOX or 5-LO) enzyme that produces Leukatriene B4 and several other leukatrienes responsible for vasodiation.

The hype included

“Through the action of an enzyme called 5-lipo-oxygenase multiple vasodilator leukotrienes are produced in the skin to cause blood vessel dilation. This enzyme is activated via many mechanisms including allergies, heat, irritation, dermatitits, etc. This is why zileuton may be one of the first true safe anti-inflammatories for vascular rosacea. The other benefits would be reduced sebum by 65% and reduced papules, pustules and acne by around 75%. There was also a significant reduction in the acne severity index as early as 4 weeks.
Zileuton will have several indications when it is approved by the FDA — it will be approved for treatment of inflammatory papules and pustules.”

Well phase II clinical trials have concluded and the results are disappointing.

“in patients with moderate to severe inflammatory facial acne did not show statistical significance in its primary efficacy endpoint.”

The study counted inflammatory, non-inflammatory and other lesions over a 12 weeks period. Unfortunately those taking Zileuton did not fair significantly better over the placebo participants.

The best news from the study was that moderate to severe acne (a base of more than 30 lesions) showed a marginally significant reduction in lesions when on Zileuton compared to placebo. Rosacea sufferers won’t take much comfort from this though.

When you consider the cost of trials, the fact that Zileuton has disappointed with acne relief, one can only think that similar investigations into rosacea relief are unlikely.

Critical Therapeutics acquired from Abbott Laboratories the worldwide rights to develop and market Zyflo for asthma. Critical Therapeutics also acquired worldwide rights to other formulations of zileuton for multiple disease and conditions including asthma, acne, chronic obstructive pulmonary disease and nasal polyps.