Another drug included in a multi-billion dollar alliance between Gilead Sciences and Galapagos has been stymied by safety concerns. The partners announced Wednesday that they are stopping a late-stage study in idiopathic pulmonary fibrosis (IPF) after an independent assessment concluded that the potential benefits of the drug, ziritaxestat, do not outweigh its risks.
That data monitoring committee’s conclusion was specific to the IPF study. But the companies said that all clinical trials for the drug would be discontinued, including a mid-stage study in systemic sclerosis.
Foster City, CA-based Gilead and Galapagos, which is headquartered in Belgium, said the committee’s conclusions about the drug followed a regular review of unblinded data. They did not specify what concerns were raised. More details will be presented at future medical meetings, they said.
Ziritaxestat is a small molecule designed to block autotaxin, an enzyme that plays a role in the scarring and inflammation characteristic of fibrotic diseases such as IPF. In IPF, scar tissue develops in the lungs.
Gilead and Galapagos were evaluating ziritaxestat in two identically designed Phase 3 studies that were expected to enroll about 1,500 patients combined. Those patients were randomly assigned to receive the test drug at either a 200 mg dose or a 600 mg dose or a placebo once daily. The main goal of the study was to assess, over the course of one year, the rate of decline in forced vital capacity, which is a measure of amount of air that can be expelled from the lungs.
The ziritaxestat setback comes nearly two months after Gilead walked away from U.S. development of another partnered compound, filgotinib. The drug, a small molecule that blocks proteins called Janus kinases, was projected to become a blockbuster seller as a treatment for rheumatoid arthritis. But last August, the FDA rejected the drug, asking for more data and raising concerns about the overall risk-benefit profile of the pill at the 200 mg dose. However, the drug went on to secure regulatory approvals in Japan and Europe.
Galapagos is taking sole responsibility for commercializing filgotinib in Europe, where it is marketed under the name Jyseleca. In Japan, Galapagos is commercializing the drug under a partnership with Eisai. Gilead is still contributing about $194 million toward commercialization of the drug in Europe and will start receiving royalties from its sales in 2024.
The partnership between Gilead and Galapagos dates to 2015, when the companies agreed to work together on the late-stage development of filgotinib, which was discovered by Galapagos. In 2019, the companies entered a new collaboration in which Gilead paid $3.95 billion up front and made a $1.1 billion equity investment in its partner. The deal gave Gilead access to six clinical-stage drugs and more than 20 preclinical compounds from Galapagos. The new alliance also amended the partnership on filgotinib, giving Galapagos a greater role in that drug’s global development and commercialization in Europe.
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