ANACOR CLINICAL STUDY OF AN2728, A NOVEL ANTI-INFLAMMATORY COMPOUND, SHOWS EFFICACY IN PSORIASIS

-- Topical Therapy Reduces TNF-alpha Production Through Inhibition of PDE-4 Enzyme --

Palo Alto, Calif. - June 6, 2007 - Anacor Pharmaceuticals, a privately held pharmaceutical company, announced today the results from its placebo-controlled Phase 1 trial of AN2728, a first-in-class topical therapy under investigation for the treatment of psoriasis. The trial showed AN2728 to be well-tolerated, with activity comparable to existing topical treatments for psoriasis.

AN2728 is the product of a focused medicinal chemistry effort to create small molecules that inhibit TNF-alpha, the inflammatory cytokine that is the target of the powerful monoclonal antibodies now marketed for the treatment of psoriasis. Company researchers have shown that AN2728 suppresses the phosphodiesterase 4 (PDE4) enzyme, leading to TNF-alpha inhibition.

"This early-stage trial demonstrated definitive anti-inflammatory activity in humans. We are encouraged that the compound decreases TNF-alpha, a cytokine known to be important in psoriasis, by the inhibition of PDE4, a well-validated anti-inflammatory target," said Karl Beutner, Anacor's chief medical officer. "A topical compound that effectively targets TNF-alpha would have great promise, and we intend to initiate further clinical trials to characterize the clinical utility of this drug in psoriasis and other inflammatory skin diseases."

Psoriatic plaques on each of the 12 patients enrolled in the trial were divided into six sections, and each of those sections was treated with a different therapy: AN2728 ointment, AN2728 cream, betamethasone, tacrolimus (Protopic) and vehicle cream and ointment. Using ultrasound, researchers measured the thickness of the inflammatory infiltrate in the psoriatic plaques and also recorded the clinical response based on an investigator global evaluation of disease severity.

As measured by decreases in the thickness of the infiltrate and clinical scores, AN2728-treated plaques improved significantly compared with vehicle treatment (p<0.001), and efficacy was comparable to that seen with betamethasone and tacrolimus. AN2728 treatment was well-tolerated in all patients.

About Psoriasis
Psoriasis is an inflammatory skin disorder that affects approximately 14 million individuals worldwide. The disorder ranges from a single, small, localized lesion in some patients to a severe, disfiguring skin condition that may be associated with disabling arthritis.

About Anacor Pharmaceuticals
Anacor, a privately held, clinical-stage pharmaceutical company, is developing novel product candidates for inflammatory, fungal and bacterial diseases based on its proprietary, small-molecule, boron-based chemistry. The company's lead product is AN2690, which is in Phase 2 trials for onychomycosis, a fungal infection of the nail and nailbed. Anacor has entered into an exclusive, worldwide agreement with Schering-Plough Corporation to develop and commercialize the drug. The company is also conducting clinical trials with two anti-inflammatory product candidates, AN2728 and AN0128.