Another clinical failure in lung disorder sends FibroGen hunting for cost savings—as shares crash

Once heralded as a potential blockbuster, FibroGen’s pamrevlumab did not live up to expectations in a phase 3 study for a chronic lung disease. It’s the second time this month that the therapy missed the mark in a clinical trial, putting the San Francisco biotech into survival mode.

FibroGen reported Monday that pamrevlumab failed on the primary endpoint versus placebo in the late-stage ZEPHYRUS-1 trial of patients with idiopathic pulmonary fibrosis (IPF). The therapy did not produce a change from baseline in forced vital capacity at Week 48, which is a measure of lung function. In IPF, the lung tissue becomes thick and stiff, causing permanent scarring over time that can make breathing difficult. Pamrevlumab also failed on the secondary endpoint of time to disease progression.

Shares of the company crashed 82% Monday morning to $2.86, compared to a Friday close of $16.05. 

It's been a rough couple months for FibroGen, with June exacting a particularly heavy toll. The company announced two and a half weeks ago that pamrevlumab failed to improve function in patients with non-ambulatory Duchenne muscular dystrophy (DMD) in a phase 3 study. And in May, FibroGen’s anemia med Evrenzo failed in that indication in a phase 3 study of patients with the blood cell disorders myelodysplastic syndromes. But the therapy nabbed an approval in China anyway the same month.

The string of bad news has sent FibroGen out to hunt for a way to move forward. The company “plans to implement a significant cost reduction effort in the U.S.” to extend the cash runway into 2026. Cash on hand was $373.6 million as of March 31, which was expected to last through 2024, according to FibroGen’s first-quarter earnings report.

FibroGen declined to comment on the specifics of the cost reduction measures, but a spokesperson said "we will be working through this in the coming weeks." 

Based on the results of ZEPHYRUS-1, FibroGen will discontinue a second planned phase 3 study called ZEPHYRUS-2, according to the release. Further results from the first study will be revealed at an upcoming medical meeting.

However, pamrevlumab will not be discontinued, according to the spokesperson. Another phase 3 readout in ambulatory patients with DMD is expected in the third quarter. FibroGen will also report late-stage data from a study in locally advanced pancreatic cancer in the first quarter of 2024 and metastatic pancreatic cancer. The spokesperson said the company is looking forward to these readouts.

In an effort to bolster its troubled pipeline, FibroGen nabbed Fortis Therapeutics' antibody-drug conjugate for prostate cancer and multiple myeloma in May. FibroGen will "deepen our focus" on earlier stage pipeline candidates, with plans to file requests for human trials for the anti-Gal9 antibody FG-3165 and FG-3163, an anti-CCR8 antibody, by the first quarter of 2024, the spokesperson noted. A phase 2 trial for the Fortis therapy, now named FG-3246, in metastatic castration-resistant prostate cancer will also be initiated in the second half of 2024.