A skin bacteria-based treatment for atopic dermatitis (AD) was successful in clinical trials, with no serious adverse effects and indications that it reduces eczema symptoms as well.
Atopic dermatitis (AD) is a common, chronic skin disorder which can have great impacts on the lives of sufferers. The disorder seems to result from the complex interplay between the skin, environmental effects and the immune system. Treatment involves a multifaceted approach that involves education, optimal skin care practices, anti-inflammatory treatment with topical corticosteroids and/or topical calcineurin inhibitors, the management of pruritus, and the treatment of skin infections. Severe flare-ups or more difficult-to-control disease may be treated with systemic immunosuppressive agents. Topical corticosteroids are the first-line treatment of choice, and seem to be prophylactic against flareups.
AD is associated with S. aureus colonisation, which induces a proteolytic breakdown of the epidermal barrier and dermal immune dysregulation. Inflammation results in further dysregulation of the skin microbial system. Commensal, coagulase-negative staphylococci (CoNS) were observed to produce bacteriocins which inhibit bacteria such as S. aureus, and these were not seen in the skin of most patients with AD. They hypothesised that reintroduction of CoNS would improve AD in patients.
Patients treated with MSB-0221, which incorporated the naturally occurring skin bacteria S. hominis (ShA9), had fewer AD-related adverse events (AEs) as compared with patients treated with a topical placebo, reported Richard L Gallo, MD, PhD, of the University of California San Diego and co-founder of the company developing MSB-0221.
“Besides its effect on decreasing the redness and itch in a subset of patients, and dramatically and rapidly decreasing the colonisation by Staph aureus, one of the unique aspects of this is that it’s specific for this organism,” said Dr Gallo. “It was not detrimental to other members of the microbiome that could help restore balance.”
Applying MSB-0221 to 54 adults, they found a reduction in S. Areus, which was associated with a significant decrease in AD symptoms compared to placebo.
The next step would be a larger, 150 patient clinical trial over 12 weeks.
“We don’t fully understand all of the ramifications, but there seems to be at least a subset of patients with atopic dermatitis whose disease is influenced and exacerbated by certain bacteria, such as Staph aureus,” said Bruce Brod, MD, of the University of Pennsylvania. “There is still sort of a chicken-and-egg aspect to the relationship. Did the skin inflammation come first or the Staph aureus?“
“This is a proof-of-concept study that provides some evidence that shifting the balance of another bacteria that’s not pathogenic might have some therapeutic benefit in some patients with atopic dermatitis,” he added. “It provides support for larger studies looking at safe bacteria to shift the flora to a more favourable environment. At this point, it’s just another piece of a puzzle that could one day lead to different therapies. It’s probably not the whole picture, but in some patients, it may play a significant role.”
Source: MedPage Today
Journal information: Nakatsuji T, et al “Development of a human skin commensal microbe for bacteriotherapy of atopic dermatitis and use in a phase I randomized clinical trial” Nature Med 2021; DOI: 10.1038/s41591-021-01256-2.