LAHAINA, HAWAII – Reassuring evidence of the long-term effectiveness and safety of dupilumab in adolescents with moderate to severe atopic dermatitis comes from a phase 3 open-label extension study of the first teenagers in the world to have received the monoclonal antibody, Lawrence F. Eichenfield, MD, reported at the SDEF Hawaii Dermatology Seminar provided by the Global Academy for Medical Education/Skin Disease Education Foundation.
Bruce Jancin/MDedge News
Dr. Lawrence F. Eichenfield
Dupilumab (Dupixent), a monoclonal antibody directed against interleukins-4 and -13 initially approved in adults, received an expanded indication from the Food and Drug Administration in March 2019 for treatment of 12- to 17-year-olds with moderate to severe atopic dermatitis (AD) on the strength of a pivotal 251-patient, phase 3 randomized trial of 16 weeks’ duration (JAMA Dermatol. 2019 Nov 6. doi: 10.1001/jamadermatol.2019.3336). But since AD is a chronic disease, it was important to learn how dupilumab performs well beyond the 16-week mark in adolescents, observed Dr. Eichenfield, professor of dermatology and pediatrics at the University of California, San Diego, and chief of pediatric and adolescent dermatology at Rady Children’s Hospital.
In addition to highlighting some of the emerging fine points of dupilumab therapy in adolescents, Dr. Eichenfield discussed the clinical implications of a potential further expanded indication for treatment of 6- to 12-year-olds, an event he considers likely in the coming months. He also described early data from an ongoing dupilumab clinical trials program in the 2- to 5-year-olds.
Long-term dupilumab in teens
Dr. Eichenfield was a coauthor of the recently published phase 3 international long-term extension study. The 40 participants experienced a mean 85% decrease from baseline at 52 weeks in EASI (Eczema Area and Severity Index) scores on 2 mg/kg per week dosing and an 84% reduction on 4 mg/kg per week dosing. This represented a substantial further improvement from week 2, when the EASI reductions were 34% and 51%, respectively.
The mean trough serum dupilumab concentrations over the course of the year were markedly lower in the 2 mg/kg group: 74 mg/L, as compared to 161 mg/L with dosing at 4 mg/kg per week (Br J Dermatol. 2020 Jan;182[1]:85-96).
“It’ll be interesting to see how this works out over time,” the dermatologist commented. “The issue of dose by weight becomes important as we start to treat younger patients because the pharmacokinetics are very different at 4 and 2 mg/kg, and it may have an impact on efficacy.”
The extension study also established the safety and effectiveness of utilizing dupilumab in combination with standard topical corticosteroid therapy, which wasn’t allowed in the pivotal 16-week trial.
Some have commented that dupilumab may be less effective in adolescents than in adults. They point to the 24% rate of an Investigator Global Assessment (IGA) of 0 or 1 – that is, clear or almost clear – at week 16 in the pivotal adolescent trial, a substantially lower rate than in the adult trials. However, Dr. Eichenfield noted that the adolescent study population was heavily skewed to the severe end of the disease spectrum, the placebo response rate was very low, and the absolute placebo-subtracted benefit turned out to be quite similar to what was seen in the adult trials. Moreover, he added, in a post hoc analysis of the pivotal trial data which utilized a different measure of clinically meaningful response – a composite of either a 50% reduction in EASI score, a 3-point or greater improvement on a 10-point pruritus scale, or at least a 6-point improvement from baseline on the Children’s Dermatology Quality Life Index – that outcome was achieved by 74% of adolescents who didn’t achieve clear or almost clear.