CDX-622 Continues To Show Promise In Ph1 MAD IV/SAD SC Data

Research evidence excerpt

CDX-622 Continues To Show Promise In Ph1 MAD IV/SAD SC Data

TD Cowen Celldex Therapeutics

Global Research June 14, 2026

• TSLP is a major driver of Type 2 inflammation and fibrosis via activity on

dendritic cells, T lymphocytes, and ILC2 cells, and its neutralization has been

shown to have clinical activity in eosinophilic and non-eosinophilic asthma.

• SCF plays an important role in mast cell (MC) survival, maturation,

activation, and recruitment as the sole ligand of KIT. Importantly,

barzolvolimab has already provided clinical POC that inhibition of the SCF-

KIT axis can provide substantial therapeutic benefit in MC driven diseases.

CDX-622 targets SCF rather than KIT as targeting two soluble ligands is

potentially better than targeting the receptors in the context of bispecific

antibodies, but the effect on MCs is expected to be largely the same.

Simultaneous inhibition of these non-redundant and complementary inflammatory

pathways may enhance clinical activity over single-target approaches in various

inflammatory, fibrotic, and allergic disorders. Additionally, CDX-622 is engineered

with Fc mutations that enhance FcRn binding (AQQ to disable effector function and

YTE to reduce clearance).

Preclinically, CDX-622 potently neutralized TSLP and soluble SCF in ex-vivo human

skin slices, and reduced mast cell genes in cynomolgus macaques. A GLP toxicology

study also assessed CDX-622 at 3, 20, and 75 mg/kg QW for 9 weeks in NHPs and

established 75 mg/kg (the highest dose tested) as the No-Observed-Adverse-Effect-

Level (NOAEL). Profound mast cell depletion was observed in tissues, but there were

no KIT-related findings such as fur discoloration or changes in bone marrow (M:E

ratio).

CDX-622 Is Being Evaluated In A 3-Part Ph1 Study In Healthy Volunteers