11 January 2022 - - Dublin-based Horizon Therapeutics plc (NASDAQ: HZNP) has submitted a supplemental Biologics License Application to the US Food and Drug Administration to expand the approved indication for Krystexxa plus methotrexate, an immunomodulator commonly prescribed by rheumatologists, the company said.

Krystexxa is currently indicated for the treatment of chronic gout refractory to conventional therapies, also known as uncontrolled gout, in adult patients, and has demonstrated rapid reduction in serum uric acid for people with uncontrolled gout.

As treatment with biologic medicines can, in some people, trigger the body's immune system to develop anti-drug antibodies, immunomodulators such as methotrexate are often used to help improve response rates.

The sBLA submission is based on the Methotrexate to Increase Response Rates in Patients with Uncontrolled Gout Receiving Krystexxa trial (MIRROR randomized controlled trial [RCT]) with supporting evidence from the MIRROR open-label trial, as well as published data from several independent case series showing improved treatment response rates through the use of Krystexxa plus methotrexate.

The MIRROR randomized controlled trial results, announced in October 2021, showed 71.0% (71 of 100 patients) of patients who were randomized to receive Krystexxa plus methotrexate achieved a complete sUA response, defined as sUA