FibroGen’s rotten run continues. The biotech reported its fourth phase 3 failure in as many months after the market closed Tuesday, flunking a second Duchenne muscular dystrophy (DMD) trial in quick succession to send it deeper into the mire.
San Francisco-based FibroGen built a broad clinical trial program around the failed DMD drug candidate, the anti-CTGF antibody pamrevlumab, on the strength of evidence its effect on a fibrosis pathway can do everything from slow the loss of muscle function to improve survival in cancer patients. However, the first set of late-phase readouts has dampened expectations.
In June, phase 3 clinical trials of pamrevlumab in non-ambulatory DMD and idiopathic pulmonary fibrosis missed their primary endpoints. The failures followed a big clinical blow to FibroGen’s oral anemia drug roxadustat.
Now, FibroGen has reported the failure of pamrevlumab in ambulatory DMD patients. The phase 3 trial randomized 73 boys aged 6 to 12 years with ambulatory DMD to receive pamrevlumab or placebo on top of systemic corticosteroids.
After 52 weeks, subjects on pamrevlumab performed no better than their peers on placebo on the North Star Ambulatory Assessment, a measure of motor abilities. The placebo-corrected mean difference of -0.528 fell short of statistical significance, causing the study to miss its primary endpoint. Pamrevlumab also failed to improve scores on multiple secondary endpoints that assessed mobility in different ways.
The setback led FibroGen to utter a familiar refrain: “We are deeply disappointed.” This time the phrase, which has been attributed to FibroGen’s chief medical officer and former CEO in the past, emerged from the lips of interim CEO Thane Wettig, who took up the post in July. Wettig’s team is now evaluating the DMD data before deciding on the next steps for the program.
FibroGen’s share price fell 22% to $1 in premarket trading, continuing a trend that has wiped 95% off the value of the company in six months. Even after the value-destroying setbacks, the biotech still has a shot at resurrecting pamrevlumab. In the first half of next year, FibroGen is scheduled to publish data from two phase 3 trials of the antibody in different pancreatic cancer settings.
The biotech is funded well beyond those readouts. Holding $361 million at the end of June, FibroGen has the money to pivot to its early-stage oncology pipeline even if its advanced assets flame out. The biotech expects to share phase 1 data on its CD46-targeting antibody-drug conjugate around the end of the year and file to study two other assets in humans next year.