FDA panel, by a whisker, votes yes on Cempra’s antibiotic

An FDA panel has voted 7-6 that Cempra’s ($CEMP) new antibiotic solithromycin should be recommended for U.S. regulatory approval--coming days after its shares plummeted by 40% on safety fears.

This is a major boost for small cap Cempra and its experimental drug, which is designed to treat community-acquired pneumonia, as in briefing docs released by the FDA a few days before the panel showed up a risk of the med raising liver enzymes compared to the generic antibiotic moxifloxacin, which can indicate damage to the organ.  

In these docs, the agency said: “A significant safety signal for hepatotoxicity was observed in the solithromycin development program,” as well as “the high rate of infusion site-related reactions.”

But on Friday the expert panel, which advises the FDA (although the agency can ignore its advice), voted unanimously that the med is as good as moxifloxacin, although nearly all the reviewers (12-1) said the biotech still hadn’t fully characterized the potential risk of liver injury.

Overall, the company got a narrow pass for a recommendation, but the panelists also recommended that Cempra do extra studies to assess the potential liver risk, should it gain approval. A final decision from the FDA should be made just before the New Year, but lingering manufacturing issues may blight its approval. 

In a Phase III study published last year, involving 863 patients, Cempra's intravenous solithromycin demonstrated noninferiority to injected moxifloxacin, sold as Avelox, in treating community-acquired bacterial pneumonia (CABP) within 72 hours.

If approved, Cempra says that solithromycin would be the first new macrolide antibiotic with an oral and IV formulation in over 20 years. The drug is a highly potent next-gen macrolide that has activity against most macrolide-resistant CABP pathogens.

Prabhavathi Fernandes, president and chief executive officer of Cempra, said: “We appreciate the meaningful discussion from today’s panel. Their supportive view and thoughtful comments on approaches to ensuring appropriate use are consistent with Cempra’s commitment to make solithromycin available to the right patients for a five to seven day course of an oral and/or IV macrolide as monotherapy for CABP.”