The FDA has awarded breakthrough therapy designation to the investigational drug dupilumab for the treatment of adults with moderate-to-severe atopic dermatitis (AD) who had an insufficient response to and/or who are not suitable for topical prescription therapy. Dupilumab blocks IL-4 and IL-13, which are required for Th2 responses. Co-developers Sanofi and Regeneron noted that the FDA's designation was supported by positive data from Phase I and Phase II studies. Results reported earlier this year showed that dupilumab was associated with significantly greater improvements in Eczema Area and Severity Index scores from baseline compared to placebo in patients with moderate-to-severe AD for whom topical treatment was not advisable or failed to adequately control disease activity.