Analysts see promise in FibroGen's early Duchenne study — now they want to see a pivotal trial
The drug, pamrevlumab, is a monoclonal antibody to connective tissue growth factor (CTGF) currently under development as a treatment for non-ambulatory DMD patients, idiopathic pulmonary fibrosis and locally advanced pancreatic cancer. On Friday, the San Francisco-based drug developer unveiled early data from a small, single arm study at the Parent Project Muscular Dystrophy conference in Orlando, Florida.
The single arm study, which will compare data to historical controls, includes 21 DMD patients who cannot walk. A preliminary analysis was conducted at 52 weeks, although the study will run for up to 156 weeks.
Data showed the drug slowed the rate of decline in pulmonary function — lung dysfunction is a common cause of morbidity and mortality in non-ambulatory patients. For instance, data showed “better maintenance” in percentage forced vital capacity (FVC) — the total amount of air exhaled — decline than natural history (decline of 5-6% per year).
The results also showed improvements in cardiac function. In ITT patients, there was an estimated increase in left ventricular ejection fraction (LVEF) percentage — total amount of blood in the left ventricle pumped out with each heartbeat — of 0.29% from baseline.
“Despite the small numbers, pamrevlumab’s effect on LVEF (positive mean percent change from baseline) appear intriguing when compared to what has been observed in natural history studies,” Stifel analysts wrote.
In a 305-patient study by McDonald et al published in 2018, LVEF of declined 0.82% annually, FibroGen noted.
Data also indicated a reduction in cardiac fibrosis, improvements in grip strength and lower declines in upper arm function.
“While early, the results highlight the drug’s wide utility in various indications (IPF and pancreatic cancer are both starting Phase III),” Jefferies Michael Yee wrote in a note, highlighting this is a $1 billion wholly-owned asset for FibroGen.
Akin to Yee, SVB Leerink’s Geoffrey Porges noted the company will need to complete a blinded, placebo controlled, randomized pivotal trial to confirm the drug’s effect. Porges continues to expect a 2022 launch for the drug.
Meanwhile, investors are focused on FibroGen’s AstraZeneca-partnered anemia drug, roxadustat, which has secured China approval and is being primed for a US marketing application later this year.
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