Sanofi Dupixent Phase 3 trial shows positive results in children with eosinophilic esophagitis as young as age 1

Naimish Patel, M.D., Senior Vice President, Head of Global Development, Immunology and Inflammation, Sanofi said, "We are incredibly excited to share results from this Phase 3 pivotal trial evaluating Dupixent in young children suffering from eosinophilic esophagitis – the first ever to show positive results across a variety of primary and secondary endpoints. The lack of treatment options for children living with eosinophilic esophagitis leaves many caregivers with the stress and burden of adapting their child's meals and their entire family's daily schedules to ensure healthy growth and development. In some cases, they must resort to off-label use of poorly studied treatments like steroids that can pose serious health risks when used long term. The faster and larger than anticipated enrollment in this trial further emphasizes the unmet treatment needs for children with EoE and underscores the significance of these first-ever positive results."

EoE is a chronic inflammatory disease that damages the esophagus and prevents it from working properly. The results seen with Dupixent in adults and children with EoE demonstrate that IL-4 and IL-13 are key drivers of the type 2 inflammation underlying this disease. In children, common symptoms of eosinophilic esophagitis include acid reflux, vomiting, abdominal discomfort, trouble swallowing, and a failure to thrive. These symptoms can impact growth and development, and can cause food-related fear and anxiety which can persist through adulthood. Diet adjustments, which oftentimes include the elimination of many foods, is the standard treatment for EoE, as well as the use of treatments not approved for the disease. These include proton pump inhibitors, swallowed topical corticosteroids, or in severe cases, a feeding tube, which may be used to ensure proper caloric intake and weight gain. Of the approximately 21,000 children under the age of 12 in the U.S. currently being treated for EoE, about 9,000 do not satisfactorily respond to the unapproved therapies they have been treated with and potentially require advanced therapy.

George D. Yancopoulos, M.D., Ph.D., President and Chief Scientific Officer, Regeneron said, "Dupixent is the first medicine to alleviate key signs of eosinophilic esophagitis in children as young as 1 year of age in a Phase 3 trial. The efficacy of Dupixent demonstrates that, in this age group, as in adults, IL-4 and IL-13 are key drivers of the type 2 inflammation underlying this debilitating disease. Eosinophilic esophagitis can turn the basic and life-sustaining act of eating into a painful experience at a point in children's lives when proper nutrition and achieving a healthy weight is critical to ensuring they grow and thrive. The positive results from this Phase 3 pediatric trial show Dupixent has the potential to improve signs of eosinophilic esophagitis and support healthy weight gain in children from their first birthday."

In the Phase 3 trial, 102 children aged 1 to 11 were randomized to receive Dupixent, in either a higher dose (n=37) or lower dose (n=31) regimen based on body weight, or placebo (n=34). At 16 weeks, 68% of children on higher dose and 58% of patients on lower dose Dupixent achieved the primary endpoint of significant histological disease remission (peak esophageal intraepithelial eosinophil count of ≤6 eosinophils [eos]/high power field [hpf]) compared to 3% of children on placebo (p<0.0001 for both). Additionally, children receiving higher dose Dupixent experienced the following changes at week 16:

• 86% reduction in peak esophageal intraepithelial eosinophil count from baseline compared to a 21% increase for placebo (p<0.0001).
• 0.88 and 0.84 reduction from baseline in disease severity and extent, respectively, as measured at the microscopic level in biopsy specimens compared to a 0.02 and 0.05 increase for placebo (both p<0.0001).
• 3.5-point reduction in abnormal endoscopic findings from baseline compared to a 0.3-point increase for placebo (p<0.0001).
• A numerical improvement in the proportion of days children experienced symptoms of EoE from baseline, as reported by caregivers (Pediatric EOE signs/symptoms questionnaire [PESQ-C]), compared to placebo, though not statistically significant. The PESQ-C is a novel endpoint developed by Sanofi and Regeneron used for the first time in this trial, designed to assess symptoms in young children through their caregivers (as signs), as children may have difficulty verbalizing their symptoms themselves.
• As part of a prespecified exploratory analysis a 3.09 percentile increase in body weight for age percentile from baseline compared to 0.29 for placebo.

Histological, anatomic and cellular secondary endpoints were also analyzed for the lower dose group, with all being nominally significant and generally comparable with the higher dose. More detailed results will be shared at an upcoming medical meeting, including additional data for the endpoints in the lower dose group.

Safety results were generally consistent with the known safety profile of Dupixent in its approved EoE indication for children and adults aged 12 years and older who weigh at least 40 kg. 

In May 2022, the U.S. Food and Drug Administration (FDA) approved Dupixent 300 mg weekly to treat patients with EoE aged 12 years and older and weighing at least 40 kg after granting the medicine Priority Review.

The potential use of Dupixent in children with EoE aged 1 to 11 years is currently under clinical development, and the safety and efficacy have not been fully evaluated by any regulatory authority.

"These data will be discussed with regulatory authorities around the world, starting with the U.S. later this year," the company stated in a release.