Adding the immunomodulator mycophenolate mofetil (MMF) to therapy with pegloticase (Krystexxa) may improve outcomes in patients with refractory gout, results of the proof-of-concept RECIPE trial suggest.
In the phase 2 trial, 19 of 22 patients randomized to received pegloticase and MMF achieved the primary outcome of serum uric acid levels below 6 mg/dL at week 12, compared with 4 of 10 patients assigned to pegloticase and placebo, reported Puja Khanna MD, MPH, of the University of Michigan, Ann Arbor, and colleagues.
“The use of MMF was associated with statistically significant and clinically meaningful impact on the proportion of subjects who achieved and maintained a serum urate of less than 6 mg/dL. Short-term concomitant use of MMF with pegloticase was generally well tolerated, and the estimated rates of adverse events were comparable between the groups,” she said during the virtual annual meeting of the American College of Rheumatology.
Pegloticase is a pegylated recombinant form of porcine uricase that has been shown to be effective in the treatment of gout in patients for whom other therapies have failed.
The drug’s use is limited, however, by immunogenicity, with high antipegloticase antibody titers associated with a loss of response.
“The PEG portion of the molecule, the polyethylene glycol component, can initiate an immune response that would cause significant infusion reactions and preclude further use of the medication for our patients,” explained Suleman Bhana, MD, a rheumatologist with Crystal Run Healthcare in New York’s Hudson Valley, who was not involved in the study.
“By trying to attenuate that immune response by whatever means one can, that could reduce the risk of these infusion reactions and lead to longevity and continuing efficacy of the medication,” he said.
Study details
The RECIPE trial was designed to test whether concomitant immunomodulation could prolong the efficacy of pegloticase therapy by dampening immune reactions.
Investigators enrolled patients 18 years and older who met 2015 ACR/European League Against Rheumatism gout classification criteria and had chronic refractory disease, defined as having symptoms inadequately controlled with oral urate-lowering therapy or a contraindication to ULT.
A total of 42 patients from five rheumatology practices were screened, and 35 were randomized on a 3:1 basis. In the intention-to-treat analysis of the results, the investigators included 32 patients: 22 in the MMF/pegloticase group and 10 placebo-treated controls who had received at least one dose of pegloticase.
Men comprised approximately 90% of the patients in each study arm, with the mean patient age around 55 years. In both groups, patients had a median of one gout flare in the prior year, and a mean duration of gout of 13 years plus a few months.
The patients’ prior urate-lowering agents included allopurinol and febuxostat, and patients had received colchicine, NSAIDs, and corticosteroids for acute gout.
The mean serum urate levels at baseline were 8.9 mg/dL in the MMF group, and 9.8 mg/dL in the placebo group.
Patients were given either MMF 1 g twice daily or a placebo during a 2-week run-in, with the assigned medications continuing for the first 12 weeks concomitantly with pegloticase. The uricase was given intravenously at a dose of 8 mg every 2 weeks for a total of 12 infusions.
As noted before, 86% of patients in the MMF arm (19 of 22) reached the primary outcome of serum uric acid levels below 6 mg/dL by week 12, compared with 40% (4 of 10) in the placebo arm (P = .01).
Week 24 serum uric acid response, a secondary endpoint, was sustained in 68% of patients in the MMF arm, compared with 30% in the placebo arm (P = .03).
“We found no significant differences between the groups in the absolute change in serum urate from baseline to week 24, or from week 12 to 24. We also did not find any differences between the treatment arms for the PROMIS [Patient Reported Outcomes Measurement Information System] or for the Gout Impact Scale,” Dr. Khanna said.
The most commonly reported adverse events included gout flares in 13% of patients in the MMF group and 3% in the placebo group, cardiac disorders in 3% versus 2%, respectively, and gastrointestinal disorders in 9% versus 2%.
Adverse events that occurred only in the MMF group included infections (3%), musculoskeletal and connective tissue disorders (18%), and respiratory events.
Three patients in the placebo arm had infusion reactions, two of which occurred during the first infusion, and one during the second. One of the reactions was considered serious and required hospitalization, but all infusion reactions resolved and none were fatal. There were no infusion reactions in the MMF arm.