The US Food and Drug Administration (FDA) has granted approval for the supplemental Biologics License Application (sBLA) of Horizon Therapeutics for the Krystexxa (pegloticase) injection, given along with methotrexate, to help uncontrolled gout patients attain a complete response to treatment.

The label expansion for Krystexxa plus methotrexate is based on the data from the randomised, controlled MIRROR clinical trial in adults with the condition.

In the trial, subjects were categorised to receive methotrexate 15mg/week or a placebo for four weeks. They subsequently received a combination treatment of Krystexxa plus methotrexate or Krystexxa along with a placebo for 52 weeks.

The proportion of serum uric acid (sUA) responders during the sixth month was the trial’s primary endpoint.

According to the findings, 71% of subjects in the Krystexxa with methotrexate arm achieved the primary endpoint compared to 39% of subjects who received Krystexxa with placebo.

This indicates a rise exceeding 30 percentage points in patient response rate during month six. 

Furthermore, 60% in the combination treatment arm attained a complete response during month 12 versus 31% of patients who received Krystexxa plus placebo.

During the treatment duration, 4% of subjects in the Krystexxa and methotrexate arm experienced infusion reactions compared to 31% who received Krystexxa with a placebo. 

No new safety signals were reported in the trial.

In March this year, the company received a priority review for the sBLA of the combination treatment. 

Horizon Therapeutics research and development executive vice-president Elizabeth Thompson said: “The approval for Krystexxa with methotrexate is the culmination of more than five years of effort and demonstrates Horizon’s commitment to working together with the gout community to improve the patient experience and outcomes. 

“Immunomodulatory therapies like methotrexate are often used with biologics to reduce the development of anti-drug antibodies and allow more patients to achieve a complete response.”

In May this year, the company received approval from the European Commission for Uplizna (inebilizumab) as monotherapy to treat adults with neuromyelitis optica spectrum disorder.