B244

B244 is an investigational **topical live biotherapeutic product** developed by AOBiome for **atopic dermatitis**, particularly mild-to-moderate disease with associated **pruritus**. It consists of a purified strain of the ammonia-oxidizing bacterium **Nitrosomonas eutropha D23** formulated as a topical spray, with additional development also reported as an intranasal spray for episodic migraine prevention. Mechanistically, B244 is intended to modulate the skin microbiome and local inflammation: the organism oxidizes ammonia and generates **nitric oxide** and **nitrite**, which are proposed to contribute anti-inflammatory and antimicrobial effects, including reduction of *Staphylococcus aureus* survival and suppression of Th2-associated cytokines such as **IL-4, IL-5, and IL-13**. In Phase 2b adult atopic dermatitis studies, twice-daily topical B244 showed significant improvements versus vehicle in itch, IGA, and EASI outcomes with generally mild, infrequent treatment-related adverse events and no serious adverse events reported. The program has been described as advancing toward global Phase 3 development, including a Japan partnership with Maruho.

Brand names

AO+ MistMother Dirt AO+ Mist

Other names

Nitrosomonas eutropha D23