Nucala Granted Priority Review For Treatment of Hypereosinophilic Syndrome


According to a drug filing and press release from Pharmaceutical Business Review, the FDA granted a priority review to GlaxoSmithKline for their humanized monoclonal antibody therapy, Nucala (mepolizumab). Currently, GlaxoSmithKline is seeking approval to use Nucala to treat patients with hypereosinophilic syndrome within the United States.

Hypereosinophilic Syndrome (HES)

Doctors aren’t really sure what causes hypereosinophilic syndrome, a group of rare blood disorders categorized by high levels of eosinophils in the blood for 6+ months. This can cause organ damage, predominantly in the skin, nervous system, heart, and lungs.

Hypereosinophilic syndrome usually occurs between ages 20 to 50, and more commonly appears in males than females. Symptoms include:

  • Diarrhea
  • Abdominal pain, nausea, and vomiting
  • Fatigue
  • Recurrent skin rashes or lesions
  • Cough and shortness of breath
  • Heart or lung disease
  • Heart failure
  • Vertigo
  • Issues with speech and vision
  • Memory loss
  • Nerve damage
  • Brain damage
  • Fever

Without treatment, hypereosinophilic syndrome can be fatal. Learn more about hypereosinophilic syndrome here.


What is Nucala (mepolizumab)?

Nucala was first approved in 2015 to treat patients with severe eosinophilic asthma, a type of asthma characterized by high levels of eosinophils. It is a monoclonal antibody therapy that targets interleukin 5 (IL-5), which helps eosinophils grow and develop. Basically, monoclonal antibodies are lab-created antibodies that can target foreign substances. Increasingly, these types of antibodies are showing extreme promise in drug development. This is based on the ability to make these therapeutics more customized and targeted, and thus more effective. In this case, by inhibiting IL-5, mepolizumab regulates and normalizes eosinophil levels.

Treating Hypereosinophilic Syndrome

GlaxoSmithKline hopes that Nucala can improve outcomes and quality of life for patients with hypereosinophilic syndrome, for which few treatments exist. In fact, if approved, Nucala will be the first targeted biologic treatment for HES.

The FDA’s Designations for Nucala

  • Priority ReviewWhen drugs are being developed and marketed, they must go through an FDA-review process as well. It can take up to 10 months for the FDA to review a drug therapy under their Standard Review process. A Priority Review designation, however, means the FDA will evaluate the drug within 6 months or less. The evaluation looks at safety and tolerability, treatment efficacy, and patient outcomes.
  • Fast Track: A Fast Track designation, according to the FDA, “is a process designed to facilitate the development, and expedite the review of drugs to treat serious conditions and fill an unmet medical need. The purpose is to get important new drugs to the patient earlier.”
    • Unmet medical needs refer to conditions with little to no therapeutic options.
    • Serious conditions refer to any conditions that impact daily functioning and quality of life, and can lead to progressively worse outcomes for patients if left untreated.
    • Receiving a Fast Track designation has its perks: more written and in-person communication with the FDA, ideas on data collection and drug development, and the ability to submit completed sections of the New Drug Application or Biologic License Application in chunks.
  • Orphan Drug: The Orphan Drug designation is granted to drug or biologic therapies designed to treat rare conditions. When granted this designation, companies receive 7 years of tax credits, as well as the exclusive right for drug development.

These designations were granted following the results of a 7.5 month Phase III study with 108 participants. The double-blind study examined the impact of 300mg mepolizumab administered every 4 weeks versus a placebo. Overall, the study found that patients treated with Nucala experienced fewer symptoms, at less intensity, than those without.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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