ATR-COSF

July 15, 2026: Azitra, Inc. (NYSE: AZTR) reported results from two separate ex vivo human skin studies supporting its ATR-COSF program (a S. epidermidis–derived supernatant containing an active recombinant human filaggrin domain, rHDfilaggrin) being developed as a cosmetic ingredient.

ATR-COSF (repeat-dose distribution study): In fresh healthy human skin explants pre-treated with TH2 cytokines to reduce endogenous filaggrin, a 2% lyophilized supernatant hydrogel showed rHDfilaggrin penetration through the stratum corneum with increasing amounts and improved distribution into the stratum granulosum after additional applications versus prior single-dose work. The formulated product showed improved concentrations versus concentrated supernatant alone. Standardized safety testing indicated the 2% formulation was non-irritating and non-corrosive to skin and eyes.

ATR-COSF (elasticity/anti-wrinkle activity model): In defatted human skin explants, hydrogel formulations with 0.0%–7.5% w/w supernatant increased elasticity dose-dependently at 20 hours post-application (1.6-fold at 0.09% to 4.4-fold at 7.5%); 0.28% w/w restored elasticity to levels historically seen in healthy skin.

Azitra said it plans further ex vivo wrinkle-model testing and is designing a human study. The release also references expected timing for initial safety/topline results for ATR-12 (Phase 1b) and ATR-04 (Phase 1/2), and an ATR-04 abstract, without dates.