This week, the US FDA announced that they approved the drug Nucala (mepolizumab) to treat patients with hypereosinophilic syndrome, a rare chronic blood disease which causes organ damage. Nucala is already available for patients with types of severe asthma and eosinophilic granulomatosis. Nevertheless, the treatment will be the first therapy approved to treat HES patients in 14 years.
Hypereosinphilic Syndrome
Hypereosinphilic syndrome is rare blood disease known for high levels of a white blood cell normally regulating the immune system, known as eosinophils. The excess of eosinophils disrupts organ functioning, causing damage throughout the body. Patients experience organ damage in varying ways, with some common areas including the heart, skin, lungs, bone marrow, and nervous system.
The new drug Nucala is approved for adults and children 12 years and older who had experienced symptoms for at least six months without any identifiable cause other than blood.
In a press release by the FDA, Dr. Ann Farrell, a director in the FDA’s Center for Drug Evaluation and Research said,
“Today’s approval marks the first time in over a decade that there is a new FDA-approved treatment option for patients with hypereosinophilic syndrome. FDA is committed to helping develop safe and effective treatment options for this group of rare and debilitating blood diseases and other rare conditions.”
The Trial Results
The drug has now undergone the many rigorous requirements required for FDA approval. The study randomized subjects and used a placebo to set a control group. The study was double-blind, meaning neither the patients nor doctors knew who had received the drug versus the placebo. The study set to measure what amount of the test subjects experienced an HES flare during the trial’s 32 weeks of treatment. According to the FDA,
“A HES flare was defined as worsening of clinical signs and symptoms of HES or increasing eosinophils (disease-fighting white blood cells) on at least two occasions.”
They found that the patients receiving Nucala had on average 50% less flare ups, with 28% of the treatment group having flare ups versus 56% of the placebo group. Any flare ups also tended to happen later into the trial. Side effects included pain in the hands, legs, and feet, and upper respiratory tract infection. Some also developed shingles infections.
This is exciting news for the HES community who have been anticipating this drug as it made its way through trials and review. Now, patients will find out if this new option is best for them.
