FDA Panel Nods Optimer's Dificid - Analyst Blog

Optimer Pharmaceuticals Inc. (OPTR) received a major boost when an advisory panel of the US Food and Drug Administration (FDA) unanimously recommended approval of its lead pipeline candidate, Dificid (fidaxomicin), for the treatment of Clostridium difficile infection (CDI) and for reducing the risk of recurrence when used for treatment of initial CDI. CDI is the most common nosocomial or hospital-acquired diarrhea.

The Anti-Infective Drugs Advisory Committee (AIDAC) voted 13-0 to recommend approval of the candidate believing that it was safe and efficacious in the treatment of CDI.

The positive recommendation was based on combined data from two late-stage studies, which revealed that Dificid was superior to ViroPharma’s (VPHM) Vancocin (the only FDA approved antibiotic for the treatment of CDI) in reducing CDI recurrence by 47%. The data further revealed improved global cure (defined as cure without a recurrence after 4 weeks of therapy) rates for Dificid compared to Vancocin. Dificid was also shown to be non-inferior to and as safe as Vancocin.

The FDA decision on Dificid is expected in May 2011. Though the FDA is not compelled to follow the advisory committee’s recommendation, it generally does so. Optimer expects to launch the antibiotic in August 2011. The candidate is also under regulatory review in the EU.

The positive recommendation does not surprise us and we expect the candidate to be approved by the FDA.

CDI is a serious illness caused by infection of the inner lining of the colon by C. difficile bacteria that produce toxins resulting in inflammation, severe diarrhea and sometimes death. It affects more than 700,000 people each year in the US. At present, metronidazole, a generic drug that is used off-label to treat CDI, and Vancocin are standard therapies used to treat CDI.

Our Recommendation

We currently have a Neutral recommendation on Optimer, which is supported by a Zacks #3 Rank (short-term “Hold” rating).

We are encouraged by the positive opinion of the advisory committee on Optimer’s lead pipeline candidate. Although we are quite optimistic regarding the approval of Dificid, our views are moderated by the competitive scenario. Several pharmaceutical and biotechnology companies have already established themselves in the market for the treatment of CDI and/or infectious diarrhea and many other companies are currently developing products which will compete with Dificid and Optimer’s another pipeline candidate Pruvel (for the treatment of infectious diarrhea). The market includes players like Pfizer (PFE), Bayer (BAYRY), Sanofi-Aventis (SNY), Roche (RHHBY), Johnson & Johnson (JNJ), ViroPharma and Salix Pharmaceuticals (SLXP). However, we are pleased to note that Dificid scores better than the current available treatment options on many parameters. We are particularly concerned about the presence of generics in the market. The uncertainty surrounding the regulatory filing of Pruvel is another area of concern.