- Gilead said Thursday its experimental JAK inhibitor filgotinib proved effective in improving the symptoms of patients with psoriatic arthritis, beating out placebo in a mid-stage study that should boost confidence in the drug's chances of success.
- The Foster City, California-based biotech simultaneously announced that a data monitoring panel for a larger study of filogtinib in ulcerative colitis gave a green light for testing to proceed into Phase 3, triggering a $15 million payment to Gilead's development partner Galapagos.
- Filgotinib is a key pipeline candidate for Gilead, which has been battered by the rapid decline in sales of its hepatitis C medicines.
Analysts hadn't placed too much weight on Gilead's Phase 2 study, called EQUATOR, largely focusing instead on read-outs from trials of filgotinib in rheumatoid arthritis expected later this year and early next.
Still, the positive data in arthritis and go-ahead in ulcerative colitis are a step forward for the drug.
EQUATOR tested filgotinib against placebo in 131 patients with moderate-to-severe psoriatic arthritis, showing 80% of study participants given Gilead's drug met the criteria for the American College of Rheumatology 20% improvement score (ACR20). Only a third of those on placebo did.
Nearly half of patients on filgotinib achieved ACR50 responses, compared to 15% on placebo.
Importantly, no thromboembolic adverse events were reported. Safety, especially related to thromboembolism, have been a particular concern for the JAK inhibitor class, hindering development of Eli Lilly's experimental drug baricitinib.
So far, filogtinib hasn't appeared to trigger thromboembolic events to the same degree in its clinical development, according to Leerink analyst Geoffrey Porges.
One patient in the filogtinib group suffered a serious infection that progressed to death, while another developed herpes zoster. Since JAK inhibitors act to alter immune response, infections are closely watched.
Detailed data from the study will be presented at a future scientific conference, Gilead said.
Attention now turns to forthcoming data from three Phase 3 rheumatoid arthritis studies, called FINCH 1, 2 and 3. Results from FINCH 2 are expected in the latter half of this year, while the other two aren't expected to read out until 2019.
Lilly's struggles with barictinib could open up an opportunity for Gilead and filgotinib but, even so, the drug faces stiff competition.
AbbVie has advanced its own JAK inhibitor upadacitinib, which notched a success in its fourth and largest Phase 3 study back in April. The drugmaker hopes to file the candidate for approval later this year.
And the immunology space has become increasingly crowded, filled with blockbuster (but aging) TNF inhibitors as well as newer drugs like Novartis' Cosentyx (secukinumab).