Horizon Therapeutics has started the MIRROR randomised controlled trial (RCT) to increase the duration of therapy for patients with chronic gout refractory to conventional therapies.

The PEGylated uric acid specific enzyme Krystexxa will be evaluated in combination with methotrexate as a strategy to increase the durability of response for patients.

The MIRROR (Methotrexate to Increase Response Rates in Patients With Uncontrolled GOut Receiving Krystexxa) RCT will evaluate methotrexate use as an immunomodulator to reduce immune response to Krystexxa in adult patients with uncontrolled gout.

As part of the trial, it will be assessed whether the combination can enhance the demonstrated response rate of Krystexxa and will confirm the safety and tolerability of the drug.

The primary endpoint of the trial will be the ability of Krystexxa with methotrexate versus the enzyme alone to maintain a serum uric acid <6 mg/dL to month six.

The MIRROR open-label (OL) evaluation, which was initiated at the end of last year, is currently fully enrolled (NCT03635957).

Horizon Therapeutics vice-president and Rheumatology therapeutic area head Paul Peloso said: “We believe in continued evaluation of our therapies to achieve the best possible outcome for every patient.

“We’ve accelerated our plans for this trial based on the response seen in recent real-world case studies and the ongoing open-label evaluation, an approach aligned with our strategy to address the burden of disease from the lens of what’s most important to patients.”

A total of 135 adult patients will be randomised and given methotrexate or placebo for four weeks.

Later on, the subjects will receive treatment with Krystexxa and methotrexate or Krystexxa and placebo for 52 weeks.

The primary endpoint will be measured at month six, followed by a six month follow-up period.