Jointly developed by Sanofi and Regeneron, dupilumab is a fully human monoclonal antibody that inhibits the signaling of the interleukin-4 and interleukin-13 pathways — it’s not an immunosuppressant.
How Dupixent Treats Eosinophilic Esophagitis
EoE is a chronic autoimmune disease in which a type of white blood cell, called eosinophil, builds up in the lining of the esophagus, the tube that connects the mouth to the stomach. The buildup is caused by reactions to foods, allergens, or acid reflux. In a person without EoE, there are no eosinophils in the esophagus, but a person with the disease will have increased numbers of eosinophils there, causing chronic inflammation and injury to the esophageal tissue, according to the American Academy of Allergy, Asthma & Immunology. This damage can make it hard to swallow and cause food to get stuck in the throat. EoE is rare, but that may be partly because it’s a newly identified condition — the first cases were described in the early 1990s. Some experts believe that people who have been diagnosed with reflux (GERD) may actually have EoE, especially if their condition hasn’t responded to treatment, according to MedlinePlus. The disease is more common in males, and people with EoE often have other allergic disease such as rhinitis, asthma, or eczema.
Drug Fills an ‘Important Unmet Need’ According to the FDA
The FDA’s approval of Dupixent for EoE was granted under “priority review” (a process that’s intended to take six months or less) and “breakthrough therapy,” a process designed to expedite the development and review of drugs that may demonstrate substantial improvement over available therapies, according to the FDA. “As researchers and clinicians have gained knowledge about eosinophilic esophagitis in recent years, more cases of the disorder have been recognized and diagnosed in the U.S.,” said Jessica Lee, MD, the director of the division of gastroenterology in the FDA’s Center for Drug Evaluation and Research in the approval release. “Today’s approval will fulfill an important unmet need for the increasing number of patients with eosinophilic esophagitis.”
Dupixent Improved Signs and Symptoms of EoE Better Than Placebo
The approval is based on data from two phase 3 trials that evaluated the efficacy and safety of Dupixent, as well as findings from an active long-term extension trial. Investigators found that an injection of 300 milligrams (mg) of Dupixent given weekly significantly improved the signs and symptoms of EoE at 24 weeks compared with the placebo as measured by the Dysphagia Symptom Questionnaire (DSQ), a scale designed to quantify swallowing difficulties. People with EoE taking Dupixent had a 69 percent and a 64 percent reduction in symptoms from baseline compared with 32 percent and 41 percent for placebo. The trials also looked at how well the drug helped achieve histological disease remission (an endpoint researchers set as a way to measure response to the drug) as measured by eosinophil count in the esophagus. Approximately 10 times as many people taking Dupixent achieved the remission goal as those on placebo — 60 percent and 59 percent compared with 5 percent and 6 percent for those in the placebo arm.
The Dosing and Cost of Dupixent
Dupixent is given in a 300 mg dose with a prefilled syringe or pen every week as an injection under the skin. It can be given in a clinic or it can be self-administered after the patient has been trained by a healthcare professional. The most common side effects associated with Dupixent include injection site reactions, upper respiratory tract infections, joint pain, and herpes viral infections. The drug is sold in cartons containing two prefilled pens or syringes, and each pen or syringe contains the 300 mg weekly dose. According to company’s website, the list price of Dupixent is $3,384.83 per carton, though most people will not pay the list price. For people paying the list price, a year of EoE therapy would add up to $88,005.58. The out-of-pocket cost of the drug depends on several factors, including private prescription drug insurance and whether the coverage considers Dupixent a preferred medication. The manufacturer offers a copay card program to help eligible commercially insured people cover out-of-pocket costs.
