VIENNA – A novel oral agent known as DS107 showed promise as a safe and effective treatment for moderate-to-severe atopic dermatitis in a phase IIa proof-of-concept study, Diamant Thaçi, MD, reported at the annual congress of the European Academy of Dermatology and Venereology.
“Clear efficacy signals in the reduction of clinical symptoms of atopic dermatitis were detected within 2 weeks of treatment, with the maximum improvement in the endpoints observed between weeks 4 and 8,” said Dr. Thaçi, professor of dermatology and head of the Comprehensive Center for Inflammation Medicine at University Hospital Schleswig-Holstein, in Lübeck, Germany.
Dr. Diamant Thaçi
Dr. Thaçi presented the results of an 8-week, double-blind, randomized, placebo-controlled, multicenter phase IIa study that included 102 patients with moderate-to-severe AD. Participants averaged a baseline Investigator Global Assessment (IGA) score of 3.5 on the 0-5 scale. They were randomized to 2 g of oral DS107 once daily or an equal quantity of mineral oil as a placebo control.
Based upon the encouraging findings, a 300-patient phase IIb study will get underway soon. It will examine the effects of 1 g of DS107 per day as well as 2 g in the hope that the lower dose will cut down on the high rate of minor GI side effects seen at 2 g/day while preserving the efficacy of the higher dose.
The primary efficacy endpoint in the phase IIa study was at least a 2-point drop from baseline in IGA plus an end-of-treatment IGA of 0 or 1, meaning clear or almost clear. In the intent-to-treat analysis, this was achieved in 21.6% of the group assigned to DS107, compared with 11.8% of controls. In the 71 participants who actually completed 8 weeks of treatment – 35 in the DS107 arm, 36 controls – the composite efficacy endpoint was achieved in 31.4% of those on active treatment and 16.7% on mineral oil.
Significant separation between the active treatment and control arms in terms of itch visual analog scores was seen by week 4. This was a particularly encouraging finding, since patients report pruritis to be the most troublesome symptom of AD, Dr. Thaçi noted.
Significantly greater improvement in quality of life as measured by the Patient-Oriented Eczema Measure (POEM) was also seen by week 4 in the DS107 group as compared with controls.
No severe adverse events occurred in the study. However, more than one-quarter of subjects interrupted or discontinued participation because of mild nausea, loose stools, and/or abdominal pain. These issues were equally common in the DS107 and mineral oil groups, and Dr. Thaçi and his coinvestigators suspect that for many patients it was simply a matter of too much oil in the stomach. The GI symptoms resolved quickly without intervention after a brief halt of therapy, but some patients never returned to participation.
“This problem can be solved in the future with a different dosing design or even a different method of delivering the DGLA,” the dermatologist added.
Asked about the significant placebo response seen in the study, Dr. Thaçi shrugged it off as “quite understandable.”
“Placebo is not always a placebo. There is the feeling of fullness in the stomach, there is some emollient effect, the continuous contact with the physician. You see this in all the clinical trials in atopic dermatitis: in the beginning, the first 2-3 weeks, you have some influence of placebo,” he said.
The placebo effect was greatly diminished in patients with more severe AD. In the subset with a baseline IGA of 4 or 5, none of the control subjects achieved the primary efficacy endpoint, while more than 20% on DS107 did, Dr. Thaçi noted.
The mechanism of benefit of DGLA is not fully understood as yet. Animal studies point to an antibacterial effect, and DGLA also reduces levels of inflammatory cytokines. Eosinophilia was reduced to a much greater extent in the DS107 group than controls.
Dr. Thaçi reported serving as a consultant to DS Pharma, the privately held biopharmaceutical company that is developing oral DS107, as well as to numerous other pharmaceutical companies.