AstraZeneca gets some good news for its late-stage gout therapy

AstraZeneca's ($AZN) gout drug lesinurad hit its primary endpoint in a Phase III trial, the company said, a welcome turn for one of the drugmaker's top prospects amid a thin slate of late-stage therapies.

Lesinurad is a selective uric acid re-absorption inhibitor that blocks the URAT1 transporter, treating the painful condition by normalizing acid excretion and reducing serum levels. In top-line results from a study on gout patients who get no benefit from standard treatments allopurinol and febuxostat, lesinurad alone significantly reduced serum levels of uric acid, AstraZeneca said.

However, on the safety side, the drug increased patients' risks of kidney trouble and led to a few serious adverse events, the company said. AstraZeneca is saving specifics for a later date, but an ugly toxicity profile could spike lesinurad's long-term hopes, and analysts will surely keep an eye on the drug's renal effects as more data come to light. Other common side effects were diarrhea, nausea and constipation, according to the company.

Furthermore, that 214-patient study focused on a small subset of gout sufferers, and it's just one facet of lesinurad's four-pronged Phase III program. The drug's success or failure will likely come down to two trials testing it in combination with allopurinol or febuxostat. AstraZeneca expects results from those NDA-supporting studies by mid-year, and if a lesinurad cocktail can meaningfully improve the lives of gout patients, the company could have a winner on its hands.

AstraZeneca has endured year after year of Phase III malaise, watching failures for the likes of fostamatinib and Onglyza weed its pipeline and sour investors. And while the company's strategy hasn't evolved much, lesinurad's promise makes for three near-term prospects that could help slow its dive off the patent cliff. Dapagliflozin--a once-rejected diabetes drug co-developed with Bristol-Myers Squibb ($BMY)--picked up an FDA panel recommendation this week, and Epanova--the cardio drug picked up in a $437 million deal for Omthera--is working its way through the agency.

Lesinurad was the center of AstraZeneca's $1.3 billion acquisition of Ardea Biosciences last year, and while the company hasn't discussed potential sales figures for the therapy, management is confident a gout-treating cocktail starring its drug can carve out some space on the market.

"We believe that combination therapy, addressing both production and excretion of uric acid, may be an effective way to treat gout patients who do not achieve treatment goals on xanthine oxidase inhibitors alone," Chief Medical Officer Briggs Morrison said in a statement.

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