Gilead Sciences, Inc. and Galapagos NV announced that the randomised, placebo-controlled phase 2 EQUATOR study of filgotinib, an investigational, selective JAK1 inhibitor, in 131 adults with moderate to severe psoriatic arthritis, achieved its primary endpoint of improvement in the signs and symptoms of psoriatic arthritis at Week 16, as assessed by the American College of Rheumatology 20 per cent improvement score (ACR20). There was an ACR20 response of 80 per cent for filgotinib versus 33 per cent for placebo (p<0.001). The ACR50 and ACR70 responses at Week 16 were also significantly higher for filgotinib versus placebo (ACR50: 48 per cent for filgotinib versus 15 per cent, p<0.001; ACR70: 23 per cent versus 6 per cent, p<0.01).

Filgotinib was generally well-tolerated in the EQUATOR trial, with no new safety signals observed and similar laboratory changes compared to those reported in previous trials with filgotinib in rheumatoid arthritis patients. The adverse event rate was similar in both groups with mostly mild or moderate events reported. There was one serious infection in the filgotinib group, a patient who experienced pneumonia with a fatal outcome. One other patient receiving filgotinib developed herpes zoster. There were no cases of opportunistic infection, tuberculosis, thromboembolism, or malignancy.

"The data from the EQUATOR study are very impressive and indicate that filgotinib has the potential to have a significant effect on signs and symptoms of psoriatic arthritis, a condition where there is still a high unmet medical need," said Dr. Philip Mease, Director of Rheumatology Research, Swedish-Providence-St. Joseph Health Systems and Clinical Professor, University of Washington, Seattle, WA.

"We are pleased to report that filgotinib remains consistent in terms of activity and tolerability, now also in psoriatic arthritis," said Dr. Walid Abi-Saab, Chief Medical Officer at Galapagos.
Detailed results from the EQUATOR trial will be submitted for presentation at a future scientific conference.

Separately, Gilead and Galapagos also announced that an independent Data Monitoring Committee (DMC) conducted a planned interim futility analysis of the filgotinib Phase 2b/3 ulcerative colitis study, SELECTION, after 350 patients completed the induction period in the Phase 2b portion of the study. The DMC recommended that the study proceed into Phase 3 as planned at both the 100 mg and 200 mg once daily dose level in biologic-experienced and biologic-naïve patients.

Galapagos is to receive a $15 million payment from Gilead for this progression from phase 2 to phase 3 in the SELECTION trial.

"We continue to see great potential with filgotinib to treat a range of inflammatory diseases," said John McHutchison, MD, chief scientific officer, head of research and development, Gilead. "As such, we are pleased with the continued progress of the development programs, including the EQUATOR results and advancing the SELECTION study into phase 3."

Initiated by Galapagos in April 2017, the EQUATOR Phase 2 trial was a multi-center, randomised, double-blind, placebo-controlled trial to assess the safety and efficacy of the selective JAK1 inhibitor filgotinib in adult patients with moderately to severely active psoriatic arthritis. EQUATOR was conducted in Ukraine, Poland, Estonia, Bulgaria, Spain, Czech Republic, and Belgium. In total 131 patients were randomised in a 1:1 ratio to receive filgotinib 200 mg or placebo once-daily administered for 16 weeks; 85 per cent of the patients were naïve to TNF treatment.

The primary objective of EQUATOR was to evaluate the effect of filgotinib compared to placebo on the signs and symptoms of psoriatic arthritis, as assessed by ACR20 at Week 16. Secondary objectives included ACR50/70 and minimum disease activity (MDA) as well as the effects of filgotinib on psoriasis, dactylitis (whole finger inflammation) and enthesitis (inflammation of the tendons).

Initiated by Gilead in late 2016, the SELECTION Phase 2b/3 trial is a multi-center, randomised, double-blind, placebo-controlled study to assess the safety and efficacy of the selective JAK1 inhibitor filgotinib in adult patients with moderately to severely active ulcerative colitis. A total of 1,300 patients are targeted to be randomised to receive filgotinib 100 mg, 200 mg, or placebo once-daily administered for 58 weeks. The primary objective of SELECTION is to evaluate the efficacy of filgotinib as compared to placebo in establishing EBS (endoscopy, bleeding, stool) remission at Week 10.

Galapagos and Gilead entered into a global collaboration for the development and commercialisation of filgotinib in inflammatory indications. The phase 2 EQUATOR trial in psoriatic arthritis is one of several Phase 2 trials in inflammatory diseases that were initiated in 2017 in addition to the ongoing FINCH phase 3 programme in rheumatoid arthritis, the DIVERSITY Phase 3 trial in Crohn's disease and the phase 2b/3 SELECTION trial in ulcerative colitis.

Galapagos is a clinical-stage biotechnology company specialised in the discovery and development of small molecule medicines with novel modes of action.