FibroGen’s Pamrevlumab Fails in Late-Stage Trial in Idiopathic Pulmonary Fibrosis

Rare Daily Staff

FibroGen said that its phase 3 ZEPHYRUS-1 trial evaluating the safety and efficacy of pamrevlumab in patients with idiopathic pulmonary fibrosis failed to meet the primary endpoint.

Idiopathic pulmonary fibrosis is a chronic lung disease characterized by a progressive and irreversible decline in lung function in which lung tissue becomes damaged, stiff, and scarred. As tissue scarring progresses, transfer of oxygen into the bloodstream is increasingly impaired, leading to irreversible loss of lung function, as well as high morbidity and mortality.

Pamrevlumab is a potential first-in-class antibody being developed by FibroGen to inhibit the activity of connective tissue growth factor (CTGF), a common factor in fibrotic and proliferative disorders characterized by persistent and excessive scarring that can lead to organ dysfunction and failure.

The study compared treatment with pamrevlumab to placebo and did not meet the primary endpoint of change from baseline in forced vital capacity (FVC) at week 48. The mean decline in FVC from baseline to week 48 was 260 ml in the pamrevlumab arm compared to 330 ml in the placebo arm. The secondary endpoint of time to disease progression (FVC percent predicted decline of 10 percent or more death) was also not met.

In the safety analysis, pamrevlumab was generally safe and well tolerated and the majority of treatment emergent adverse events were mild or moderate. Treatment-emergent serious adverse events were observed in 28.2 percet of patients in the pamrevlumab group and 34.3 percent of patients in the placebo group.

Based on the results of ZEPHYRUS-1, ZEPHYRUS-2, the second phase 3 clinical trial, will be discontinued. FibroGen plans to communicate the results of the ZEPHYRUS-1 study at an upcoming medical forum.

“We are deeply disappointed that these results do not support pamrevlumab as a new treatment for IPF,” said Mark Eisner, chief medical officer of FibroGen. “FibroGen would like to thank the patients and clinical trial investigators for their dedication to participating in this study.”

The company said it plans a deep cost reduction to extend its cash runway to 2026.

Photo: Mark Eisner, chief medical officer of FibroGen