Filgotinib Safety, Efficacy for RA Demonstrated Up to 156 Weeks in DARWIN 3

New results of a 3-year, open-label extension study examining filgotinib demonstrate the therapy’s ability to maintain safety and efficacy in patients with rheumatoid arthritis.

The DARWIN 3 study, which is an extension of an earlier phase 2b studies, indicated filgotinib was well-tolerated and there was no apparent safety difference between patients receiving filgotinib mono therapy or filgotinib in combination with methotrexate.

Presented at the 2019 American College of Rheumatology annual meeting in Atlanta, GA, the study examined patients from the 24-week DARWIN 1 and DARWIN 2 studies. From these studies, investigators identified a cohort of 739 that were monitored for 156 weeks—of these patients, 242 received filgotinib monotherapy and 497 received combination therapy with methotrexate.

At week 156, 40% of patients receiving filgotinib monotherapy and 45.5% receiving combination therapy achieved ACR70 response. These numbers climbed to 89.7% and 87.2%, respectively, when examining ACR20 response.

At week 156, 59.9% remained on study treatment. Among the reasons for discontinuation were adverse events (26.5%) and request of patient (9.1%). Additionally, investigators noted serious treatment emergent adverse events occurred in 45 (9.1%) and 33 (13.6%) of patients in the filgotinib monotherapy and combination groups, respectively. A total of 5 deaths occurred in the study—investigators noted none of these deaths occurred after week 132.

For more on the clinical takeaways from the 156-week data on filgotinib for the treatment of rheumatoid arthritis, MD Magazine® sat down with John Sundy, MD, PhD, senior vice president of Inflammation and Respiratory Disease with Gilead Sciences.

MD Mag: What do the 156-week data tell us about filgotinib?

Sundy: The Darwin 3 study, which is the week-156 data you referred to, is really the extension of the phase 2 program for filgotinib in rheumatoid arthritis, but what we're actually demonstrating or showing a lot of data in the context also of the FINCH program, which is the phase 3 program that had 3 trials enrolling about 3300 patients across the spectrum of treatment experience for patients from methotrexate naive, to methotrexate, inadequate responders, to biologic inadequate responders.

The great thing about the DARWIN 3 study is that it was an extension of a large phase 2 program that Galapagos conducted in rheumatoid arthritis with filgotinib. So, it's enabled us to see results long term results in patients from that program, and what we're reporting today is the week 156 data, but that study continues and we now have patients out to beyond five years of treatment as well.

So, I think that's a really great attribute of the program that Galapagos conducted in phase 2 and it enables us to, to file for approval with a fairly large long term data set, on top of our phase 3 program, I think the key takeaways from the DARWIN 3 study are a couple things. One, is that the safety profile that we've observed over time has continued to hold true and, particularly, when you look at things that are captivating interests now such as deep venous thrombosis and thromboembolism, with JAK inhibitors, but also serious infection rates and herpes zoster reactivation rates as well too. All of which, we think show up very good profile and are supportive of the data that we have in our phase three programs.