FibroGen starts patient enrollment in FG-3019 Phase 2 study for idiopathic pulmonary fibrosis treatment

FibroGen, Inc. (FibroGen), announced today that patient enrollment has started in a new Phase 2 clinical study of FG-3019 in patients who suffer from idiopathic pulmonary fibrosis (IPF).

IPF is a debilitating and life-threatening lung disease characterized by a progressive scarring of the lungs that diminishes functional lung volume and hinders oxygen uptake. The cause of IPF is not known, and approximately two-thirds of IPF patients die within five years after diagnosis.

The FibroGen randomized, double-blind, placebo-controlled study is designed to evaluate the safety and efficacy of FG-3019 in IPF patients. The primary endpoint of the study is lung function, as measured by change in forced vital capacity (FVC). Secondary endpoints include change in lung fibrosis as measured by quantitative high resolution computed tomography (HRCT) scans of the chest. The study is expected to enroll approximately 90 patients for 45 weeks of treatment at centers in the United States.

The design of this new placebo-controlled study builds on the encouraging findings from an ongoing open-label Phase 2 study of FG-3019 in patients with IPF in which a majority (68% to 71%) of the patients who have completed the trial experienced at most modest declines of FVC (less than 5%), and 24% to 26% of patients who have completed the trial experienced improvement in pulmonary function. In the on-going, open-label study, two cohorts with a total of 89 IPF patients were treated with two different doses of FG-3019. Results suggest a strong correlation between improved fibrosis and improved pulmonary function, as well as trends for improved patient-reported outcomes associated with improved fibrosis. To date, FG-3019 has been well tolerated by IPF patients.

Nineteen of the 33 patients in the first cohort who completed 48 weeks of treatment were subsequently enrolled in a one-year extension study. Interim analysis indicates that 4 of the 12 patients who completed one year of the extension study experienced only modest FVC decline (less than 5%) by the end of the second year, whereas another 4 of the 12 patients have FVC values greater than baseline values upon study entry 2 or more years earlier. Before rolling over from the initial first-year treatment period to the extension treatment period, patients were taken off therapy for an average of 11 weeks, during which first-year data was compiled and analyzed. Consequently, the end of the second year of treatment represents actual durations of 2 to 2.5 years from entry into the original study.

Frank H. Valone, MD, Chief Medical Officer of FibroGen, said, "Based on long-term data from a FibroGen extension study cohort, a subset of patients appears to experience prolonged disease stabilization or disease improvement nearly two years or more after starting treatment with FG-3019. The observation of IPF fibrosis improvement is without clinical precedent and directly challenges the widely held view that improvement in fibrosis is not a therapeutic possibility. We believe that our study will continue to support the strong and growing interest in our FG-3019 program within the clinical community, and we are working closely with investigators to identify and enroll eligible subjects afflicted with idiopathic pulmonary fibrosis."

The new Phase 2 study randomizes patients at a ratio of 1:1 to receive either FG-3019 or a matching placebo, both to be administered by intravenous infusion every three weeks over a 45-week period. Patients in the FG-3019 treatment group whose lung function stabilizes or improves and all patients in the placebo group will be eligible to participate in an unblinded treatment extension for an additional 45 weeks.

Patient eligibility criteria for the Phase 2 study include the following:

• Diagnosis of IPF centrally confirmed by High Resolution Computed Tomography (HRCT) and/or by surgical biopsy
• 55% to 90% of FVC % predicted
• HRCT extent of fibrosis measured between 10% to 50% for reticular fibrosis and less than 25% for honeycomb fibrosis
• Diffusing capacity of the lung for carbon monoxide (D_lco) greater than 30% predicted