ANACOR ANNOUNCES PHASE 2B TOP-LINE RESULTS FOR AN2728 IN PSORIASIS

Palo Alto, CA—June 15, 2010—Anacor Pharmaceuticals today announced positive clinical trial results for its lead phosphodiesterase-4 (PDE4) inhibitor, AN2728, a novel topical anti-inflammatory compound derived from Anacor’s boron chemistry platform. These results were obtained from a multi-center, Phase 2b, randomized, double-blind, dose-ranging, bilateral trial comparing AN2728 ointment, 0.5% and 2.0%, applied once or twice daily, to vehicle in 145 patients with mild-to-moderate plaque-type psoriasis. Compared to those treated with vehicle, psoriasis plaques treated with AN2728 achieved greater improvement in the Overall Target Plaque Severity Score (OTPSS) in a significantly higher proportion of patients after six weeks in the 2.0% AN2728 twice daily dosing group (P <0.001), which was the primary endpoint of the trial. A doseresponse was also observed across the four dosing groups for this outcome. Additionally, of those plaques treated for 12 weeks with 2.0% AN2728 twice daily, 54 percent achieved complete or near complete clearance with at least a two-grade improvement from their baseline severity score.

"This is the third Phase 2 trial that we have completed with AN2728 and we are pleased that the results are consistent with the statistically significant efficacy that we’ve seen in each of the previous trials," said David Perry, Chief Executive Officer of Anacor. "We believe that the safety and efficacy results observed in all three trials allow us to differentiate AN2728 from the topical corticosteroids and vitamin D analogs which are limited by their long-term safety and/or their tolerability profile. We look forward to initiating a Phase 3 study for AN2728 in mid-2011."

The randomized, double-blind, vehicle-controlled, multicenter, dose-ranging trial evaluated the safety and efficacy of AN2728 ointment, 0.5% and 2.0%, applied once or twice daily for 12 weeks for the treatment of mild-to-moderate plaque-type psoriasis. Taking advantage of the characteristically symmetric location of psoriasis plaques on the body, the trial was designed to have each of the 145 patients randomly assigned to apply AN2728 ointment, 0.5% or 2.0%, once or twice daily to one target plaque and the vehicle ointment to a similar target plaque usually on the opposite side of the body. Treatments were generally well tolerated with no serious adverse events reported. Anacor intends to present full results from this Phase 2b trial at an appropriate future scientific meeting.

About Psoriasis
Affecting approximately 10 million people worldwide, psoriasis is an inflammatory skin condition characterized by thickened red scaly plaques typically found on the elbows, knees, trunk and scalp.

About Anacor Pharmaceuticals
Anacor is a biopharmaceutical company focused on discovering, developing and commercializing novel small-molecule therapeutics derived from its boron chemistry platform. Anacor has discovered and is developing five clinical compounds, including its three lead programs: AN2690, a topical antifungal for the treatment of onychomycosis; AN2728, a topical anti-inflammatory for the treatment of psoriasis and AN3365, a systemic antibiotic for the treatment of infections caused by Gram-negative bacteria. The Company is developing AN3365 and other systemic antibacterial therapeutics under a research and development agreement with GlaxoSmithKline. For more information visit www.anacor.com.

Forward-Looking Statements
This press release may contain forward-looking statements that relate to future events and involve known and unknown risks, uncertainties and other factors that could cause actual levels of activity, performance or achievement to differ materially from those expressed or implied by these forward-looking statements. These statements reflect the views of Anacor as of the date of this press release with respect to future events and, except as required by law, it undertakes no obligation to update or revise publicly any forwardlooking statements, whether as a result of new information, future events or otherwise after the date of this press release.

Contact:
Anne Bowdidge
Investor Relations
650-543-7575