Ferring's C. difficile drug overcomes skepticism to secure FDA committee nod

Ferring Pharmaceuticals’ biotherapeutic passed an FDA committee vote despite some skepticism from a handful of members, setting up the asset for potential approval to treat Clostridioides difficile infection.

The FDA’s Vaccines and Related Biological Products Advisory Committee voted 13 to 4 that Ferring's data demonstrated RBX2660 is effective at reducing the recurrence of C. difficile after antibiotic treatment. 

The data reviewed by the committee spanned six studies with a total of 1,061 participants, of which 978 were treated with the rectally administered RBX2660, Ferring said in a Sept. 22 release. RBX2660 is a microbiota-based live biotherapeutic designed to deliver a broad range of microbes to the gut to reduce C. difficile infection.

Not every member of the committee was convinced by the data, however. Jay Portnoy, M.D., said the drug had “statistically just squeaked by” and appeared to show “very moderate beneficial effect.”

“Every doctor is going to feel obligated to prescribe it, every patient is going to demand it, and yet only one out of eight patients are going to benefit from it,” Portnoy, who voted against approval, said during the meeting.

Switzerland-based Ferring unveiled data from its most recent phase 3, dubbed PUNCH, in May 2021. The results showed superiority of RBX2660 at reducing recurrence of C. difficile infection over placebo. Specifically, the therapy saw 70.4% of patients free of the infection at eight weeks after treatment, compared to 58.1% in the placebo cohort. The drug also had a comparable safety profile, Ferring noted at the time.

“Patients with recurrent C. difficile infection currently have limited treatment options,” said Paul Feuerstadt, M.D., of Yale University School of Medicine, in the release. “The committee’s vote is a step toward potentially addressing the debilitating cycle of recurrence and the suffering faced by these patients,” added Feuerstadt, who led Ferring’s last phase 3 trial.

C. difficile causes an estimated half a million illnesses and tens of thousands of deaths each year in the U.S. alone, according to the U.S. Centers for Disease Control and Prevention, which classes the the infection a major public health threat.

Ferring has another therapy in phase 3 trials for C. difficile in the form of the oral drug RBX7455. The company is also awaiting an FDA decision on its bladder cancer drug nadofaragene firadenovec.