FibroGen, Inc. (FibroGen) announced today the presentation of clinical data at the American Thoracic Society (ATS) International Conference supporting the safety and efficacy of FG-3019 in patients with idiopathic pulmonary fibrosis (IPF), a debilitating and life-threatening lung disease for which there is currently no approved therapy in the United States. FG-3019 is an investigational monoclonal antibody that inhibits the activity of connective tissue growth factor (CTGF), a central mediator of fibrotic disease.
Today's presentation focused on patients in the first cohort of a Phase 2a study of FG-3019 who completed one year of treatment as well as patients in the first cohort who continued to receive treatment for a total of two years.
Consistent with previous results, FG-3019 was well tolerated in IPF patients treated for up to two years. No serious adverse events were considered to be related to treatment with FG-3019.
The study evaluated changes in pulmonary function, changes in pulmonary fibrosis, and patient reported outcomes, a measure of overall patient quality of life. The study employed quantitative high resolution computed tomography, or HRCT, which is an accurate and reproducible method to measure changes in the percentage of the patient's lung tissue that is fibrotic. Recent publications based on similar quantitative HRCT methods have identified an association between worsening pulmonary fibrosis and mortality in IPF.
The study enrolled patients with a wide range of IPF severity to assess safety and efficacy across a broad spectrum of the disease. Efficacy data from patients with mild to moderate disease (n=37) were analyzed in the presentation, a patient population similar to those evaluated in other recent IPF clinical trials. Thirty-three of these patients completed 48 weeks of treatment.
After 48 weeks of treatment, twelve of the 33 patients (36%) had improved fibrosis as measured by quantitative HRCT. Prior to this finding, improved fibrosis had never been reported in IPF patients. An additional two patients had stable fibrosis for a total of 14 patients (42%) with improved or stable fibrosis.
Change in forced vital capacity, or FVC, also correlated with changes in fibrosis (p=0.005, r= -0.476) at 48 weeks. Patients with improved or stable fibrosis also had improved pulmonary function at week 48 with FVC change of +0.05 liters compared to -0.24 liters for patients with worsening fibrosis (p=0.006).
The St. George's Respiratory Questionnaire (SGRQ) is often used in IPF trials to assess changes in patients' perceptions of disease impact on their quality of life. Improvements in the SGRQ symptoms score correlated significantly with improvements in fibrosis at both 6 months and 12 months (p<0.05) assessments.
Eighteen of the 33 patients who completed the primary study enrolled in an extension study to continue FG-3019 treatment for a second year. Fourteen of these patients completed the second year of treatment. Four of the 14 evaluable patients experienced a prolonged improvement in pulmonary function through the second year of study, with average change in FVC from the original baseline of +0.2 liters. Six had modest decline in pulmonary function (average change from baseline after 2 year of -0.2 liters) and another 4 showed a severe decline (average change in FVC from the original baseline of -0.6 liters) at the end of the second year. Patients who experienced modest decline or improvement in FVC experienced only a modest increase in fibrosis, whereas those who experienced a severe decline also showed the greatest increase in fibrosis.
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