A Phase III trial of epaminurad, a selective oral uricosuric agent for gout, has met its primary endpoint and demonstrated statistical superiority over an active comparator at its lead dose, putting South Korea-based JW Pharmaceutical (KRX: 001060) on track for a domestic new drug application (NDA) submission targeting approval in 2027.
The confirmatory Phase III study enrolled 612 gout patients across 52 centers in South Korea, Taiwan, Thailand, Malaysia, and Singapore. At the primary endpoint — the proportion of patients achieving serum uric acid (sUA) below 6 mg/dL across the final three measurements of the treatment period — the epaminurad 6 mg arm reached 50.0% (76/152 patients) versus 38.3% (59/154 patients) in the febuxostat 40 mg control arm. The response rate difference of 12.0 percentage points (95% CI: 1.26–22.6) satisfied non-inferiority criteria and crossed the threshold for statistical superiority. Treatment-emergent adverse events, adverse drug reactions, serious adverse events, and adverse events of special interest were comparable between the two arms, with no drug-related deaths reported.
Epaminurad selectively inhibits the human uric acid transporter-1 (hURAT1), blocking renal reabsorption of uric acid and promoting its excretion — a mechanistic approach that differs from the xanthine oxidase inhibition used by febuxostat and allopurinol, which reduce uric acid production rather than increase its clearance.
The 9 mg dose did not meet non-inferiority criteria against febuxostat 80 mg, with response rates of 59.6% versus 63.3% and a roughly 4 percentage point gap. JW Pharmaceutical said it plans subgroup analyses and will explore a separate regulatory strategy for the higher dose.
Epaminurad is an internally developed JW Pharmaceutical asset with a partially partnered global rights structure. JW licensed development and commercialization rights in China, Hong Kong and Macau to Simcere Pharmaceutical in 2019, while retaining rights elsewhere. The company is now seeking additional out-licensing agreements covering major markets including the US and Europe, making the Phase III dataset potentially important to both its South Korean NDA and international partnering strategy.