Paul Foster, M.D., chief medical officer at Xencor, said: "A previously completed Phase 1a study of intravenous administration of XmAb7195 has shown potent suppression of IgE, in particular demonstrating the rapid clearance of IgE from the circulation, while being generally well tolerated by patients.
"We expect to report interim data from this Phase 1b subcutaneous trial in 2017."
Complete data results from a Phase 1a, first-in-human study for IV administration of XmAb7195 were presented at the American Thoracic Society (ATS) 2016 International Conference in May 2016.
Data showed that IV XmAb7195 was generally well tolerated with transient, asymptomatic thrombocytopenia reported at doses ≥2.0 mg/kg, and induced rapid and extensive depletion of serum IgE at all doses tested, including in high IgE subjects.
The poster is available on the Events and Presentations page of Xencor's website under "Archived Scientific Presentations" at http://investors.xencor.com/events.cfm.
For more information about this Phase 1b subcutaneous XmAb7195 clinical trial please visit to www.clinicaltrials.gov (identifier: NCT02881853).
About XmAb 7195
A first in class monoclonal antibody that targets IgE with its variable domain and uses Xencor's XmAb Immune Inhibitor Fc domain to target FcgRIIb, resulting in three distinct mechanisms of action for reducing IgE levels for the potential treatment of allergic disease. XmAb7195 acts by 1) sequestering free IgE to block IgE signaling, 2) suppressing B-cell differentiation into IgE-secreting plasma cells, and 3) clearing IgE from circulation.
Total IgE reduction differentiates XmAb7195 from other anti-IgE therapeutic antibodies that actually increase total IgE levels.
Because total IgE assays, unlike free IgE assays, are readily available to clinicians, the effect of XmAb7195 on total IgE levels could enable for the first time simple monitoring, and potentially adjustment, of anti-IgE therapy.
About Xencor's XmAb Immune Inhibitor Technology
FcγRIIb (IIb), also called CD32b, is a receptor for Fc domains on B cells and other immune cells. When engaged, the IIb receptor blocks immune activation pathways and traffics bound soluble antigens out of circulation.
Xencor has discovered a series of Fc domain variants with up to a 400-fold increase in binding affinity to FcγRIIb derived from just two amino acid changes.
These XmAb Immune Inhibitor Fc domains greatly heighten the properties of IIb receptor engagement and have potential as building blocks for drug candidates in autoimmune, allergic and inflammatory diseases.