Characterization of AQX-1125, a small-molecule SHIP1 activator: Part 2. Efficacy studies in allergic and pulmonary inflammation models in vivo.

BACKGROUND: The efficacy of AQX-1125, a small-molecule SH2-containing inositol-5'-phosphatase 1 (SHIP1) activator and clinical development candidate, is investigated in rodent models of inflammation.

EXPERIMENTAL APPROACH: AQX-1125 was administered orally in a mouse model of passive cutaneous anaphylaxis (PCA) and a number of rodent models of respiratory inflammation including: cigarette smoke, LPS and ovalbumin (OVA)-mediated airway inflammation. SHIP1 dependency of the AQX-1125 mechanism of action was investigated by comparing the efficacy in wild-type and SHIP1-deficient mice subjected to an intrapulmonary LPS challenge.

RESULTS: AQX-1125 exerted anti-inflammatory effects in all of the models studied. AQX-1125 decreased the PCA response at all doses tested. Using bronchoalveolar lavage (BAL) cell counts as an end point, oral or aerosolized AQX-1125 dose dependently decreased the LPS-mediated pulmonary neutrophilic infiltration at 3-30 mg kg⁻¹ and 0.15-15 μg kg⁻¹ respectively. AQX-1125 suppressed the OVA-mediated airway inflammation at 0.1-10 mg kg⁻¹. In the smoke-induced airway inflammation model, AQX-1125 was tested at 30 mg kg⁻¹ and significantly reduced the neutrophil infiltration of the BAL fluid. AQX-1125 (10 mg kg⁻¹) decreased LPS-induced pulmonary neutrophilia in wild-type mice but not in SHIP1-deficient mice.

CONCLUSIONS: The SHIP1 activator, AQX-1125, suppresses leukocyte accumulation and inflammatory mediator release in rodent models of pulmonary inflammation and allergy. As shown in the mouse model of LPS-induced lung inflammation, the efficacy of the compound is dependent on the presence of SHIP1. Pharmacological SHIP1 activation may have clinical potential for the treatment of pulmonary inflammatory diseases.