Galapagos NV recently announced positive results of treatment with the selective inhibitor of JAK1 named filgotinib as monotherapy once per day in improving the symptoms and signs of moderately severe active rheumatoid arthritis (RA). These results are part of the DARWIN 2 Phase 2B clinical study.
After 12 weeks of treatment, results also revealed that all doses of the drug were effective and demonstrated statistically significant improvements in ACR20 response in comparison to placebo. Results also revealed statistically significant ACR50 response and a decrease in DAS28(CRP) at all dose levels.
In the study, Filgotinib was well tolerated and hemoglobin levels improved. Results from these first 12 weeks corroborate previous studies on the efficacy and safety of filgotinib.
DARWIN 2 is a 24-week ongoing, placebo-controlled, double-blind clinical study of filgotinib, given once per day at 3 distinct dose levels. The 12-week results are from a population of 283 patients with moderate to severe RA that had poor response to methotrexate. For the study, patients received Filgotinib or placebo as a monotherapy. The company is aiming to report the results of the 24-week treatment during the 3rd trimester of 2015.
Results from the 12 weeks of treatment showed a rapid onset of efficacy, ACR20 response, investigator’s evaluation of RA and statistical significant patient-reported improvements following one week of treatment. Results revealed only 1.8% of patient discontinuations.
Serious adverse events were observed in 2% of the patients. From these, the most common were Infections and infestations (15% for filgotinib versus 10% for placebo), with only 0.7% of serious infections that remain blinded for the treatment group.
Consistent with the selective inhibition of JAK1, treatment with filgotinib led to an improvement in hemoglobin (increase from baseline of up to 0.4 g/dL, or 3.4%). Regarding the anti-inflammatory activity of the compound, a decline in neutrophils was observed during the first 4 weeks of treatment, and after the treatment the levels remained stable in the normal range. There were no discontinuations related to neutropenia, anemia, or an increase in transaminases. Results also showed dose-dependent and well balanced increases in HDL and LDL.
“The results from the DARWIN 2 study are truly exciting, with consistent efficacy meeting key endpoints across the different geographical regions. If confirmed in longer-term studies, selective inhibition of JAK1 by filgotinib may lead to a differentiated safety profile without compromising efficacy,” said Professor Arthur Kavanaugh, MD, Professor of Medicine at the University of California, San Diego (UCSD) School of Medicine, and Principal Investigator for DARWIN 2 in a recent news release.
“Once-daily monotherapy in DARWIN 2 led to similar efficacy as that observed at the high doses in DARWIN 1, where patients took once- or twice-daily filgotinib with methotrexate. And we found the same fast onset of action. These data support our belief that filgotinib could be used prior to initiating anti-TNF therapy,” said Dr Piet Wigerinck, Chief Scientific Officer of Galapagos in the news release. “Selective inhibition of JAK1 increases hemoglobin, which is important to improve the patient’s fatigue and thereby overall condition. These 12-week monotherapy results in RA further support our belief that filgotinib has a promising future to address a significant medical need. We look forward to the final 24 week data for both DARWIN 1 and 2, later this year.”