AstraZeneca has reported data from a Phase III trial showing that its investigational gout drug lesinurad hit primary targets by reducing a key marker of the condition, but only at the higher dose.

According to findings from the CRYSTAL trial, a combination of lesinurad (400mg) and Takeda's Uloric (febuxostat) lowered serum uric acid (sUA) levels to a significantly greater extent than the latter alone (76.1% versus 46.8%, respectively) by month six. The 200mg dose tested also helped more subjects reach the target sUA, though the difference was not significant.

Unfortunately for AZ, the lower dose is the one under review on both sides of the Atlantic.

Among the key secondary endpoints, the lesinurad/Uloric combo did not result in a significant difference in the proportion of subjects achieving a complete resolution of at least one tophus (deposits of uric acid crystals in joints and skin) by month 12. But both doses of AZ’ drug did result in greater total tophus area reduction compared to Uloric alone, the firm noted.

On the safety side, the most common adverse events observed in the CRYSTAL study with the lesinurad groups compared to Uloric alone were nasopharyngitis, hypertension and headache, and those taking AZ’ drug experienced a higher incidence of predominately reversible serum creatinine elevations.

According to the drugmaker, which acquired lesinurad through its $1.26 billion acquisition of Ardea Biosciences in June 2012, there is high unmet need for patients with gout as around half do not achieve recommended sUA goals with the current standard of care.