Following a review of unblinded data, Galapagos NV and Gilead Sciences have decided to halt the phase 3 ISABELA studies evaluating the investigational autotaxin inhibitor, ziritaxestat, in patients with idiopathic pulmonary fibrosis.

The efficacy and safety of ziritaxestat was being evaluated in 2 identical phase 3 studies ( NCT03711162 and NCT03733444) aiming to enroll approximately 1500 patients with idiopathic pulmonary fibrosis. Patients were randomly assigned to receive ziritaxestat 200mg or 600mg orally once daily or placebo, in addition to standard of care treatment. The primary end point was the rate of decline of forced vital capacity until week 52.

The decision to halt the studies was made after a regular review of unblinded data by an independent data monitoring committee showed that the benefit-risk profile of ziritaxestat did not support its continued use. Investigators will be contacting study participants to discontinue treatment with ziritaxestat. Detailed data from the studies will be presented at future medical meetings.

Additionally, all clinical trials investigating ziritaxestat, including the phase 2a NOVESA trial for systemic sclerosis, will be discontinued.

“We are very disappointed not to be able to bring a novel medication to patients suffering from such a devastating disease with high unmet need,” said Dr Walid Abi-Saab, Chief Medical Officer of Galapagos. “We intend to learn from this data in our continued commitment to develop therapies in IPF and fibrosis.”


Galapagos and Gilead discontinue ISABELA phase 3 trials in IPF. [press release]. Foster City, CA and Mechelen, Belgium: Galapagos NV and Gilead Sciences; February 10, 2021.