FDA Denies Approval for New Antibiotic Solithromycin

Roni Shye
Roni Shye, PharmD BCGP BCACP, is a licensed pharmacist in the states of Florida, Ohio, and Pennsylvania.
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Manufacturers have to go through a rigorous process to get approval from the U.S. Food and Drug Administration (FDA). Typically, drugs have to pass through four successful phases of clinical trials and manufacturers have to submit a New Drug Application (NDA) in order to get FDA approval. You hear about new drugs being approved all the time, but occasionally a drug gets denied.

Recently, the FDA denied the New Drug Application (NDA) from Cempra Pharmaceuticals for their new antibiotic, solithromycin.

What is a new drug application (NDA)?

A new drug application (NDA) is the way that manufacturers apply for drug approval from the FDA. This application is supposed to tell the drug’s whole story, including what happened during the clinical tests, what the ingredients of the drug are, the results of the animal studies, how the drug behaves in the body, and how it is manufactured, processed, and packaged.

The FDA tends to look at three key points when deciding if they are going to accept a drug’s NDA:

  1. Whether the drug is safe and effective, and whether the benefits outweigh the risks.
  2. Whether the drug’s proposed labeling (package insert) is appropriate and descriptive.
  3. Whether the methods used in manufacturing the drug, and the protocol used to maintain the drug’s quality, are adequate to preserve the drug’s identity, strength, quality, and purity.

Why was the NDA for solithromycin denied by the FDA?

The FDA decided to deny the new drug application for solithromycin for a few reasons. For one, the FDA asked for more clinical safety information about the toxicity of the drug, and the possible negative hepatic adverse effects. The FDA has requested that Cempra Pharmaceuticals complete a larger comparative study of at least 9,000 patients to more closely evaluate the potential for liver toxicity in patients.

The FDA also noted that the facilities in which solithromycin will be manufactured had some deficiencies. The manufacturer must resolve these deficiencies in these two manufacturing plants in order to get approval.

Keep in mind that this doesn’t necessarily mean that solithromycin won’t get approved in the future. It just means that the FDA wants to ensure the utmost safety of the drug.

What is solithromycin indicated for?

Solithromycin is indicated for the treatment of moderate to moderately-severe community acquired bacterial pneumonia (CABP) and urethritis.

What phase of clinical trials was solithromycin in?

Solithromycin was in stage 3 clinical trials. Generally, a phase three clinical trial is completed to confirm a medication’s effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.

In fact, during its clinical trials, solithromycin has been shown to be effective! The FDA didn’t request any more information on the drug’s efficacy when denying the NDA.

If solithromycin gets approved, what dosage forms will it be available in?

Solithromycin will be available in oral and intravenous dosage forms with plans for an ophthalmic form in the future.

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