The purpose of this study is to assess the safety/tolerability and efficacy of using ustekinumab in subjects with common variable immunodeficiency CVID or selective IgG subclass deficiency (functional agammaglobulinemia) who have associated symptomatic gastrointestinal inflammation (CVID enteropathy). Ustekinumab (a Food and Drug Administration \[FDA\] approved drug) is a monoclonal antibody to interleukin (IL)-12/23p40. CVID is a clinically heterogeneous disorder characterized by decreased serum immunoglobulin IgG and IgA levels. In addition to chronic or recurrent pyogenic sino-pulmonary infections, many patients develop non-infectious gastrointestinal manifestations that can be disabling or fatal. Currently there is no standard therapy for the associated gastrointestinal disease outside of empiric nutritional intervention for weight loss, anti-diarrheal agents, and non-specific anti-inflammatory agents.
Recently, gut inflammation complicating functional hypogammaglobulinemia due to CVID and selective IgG subclass deficiency has been characterized as a T helper type 1 (Th1) inflammatory response, with excess IL-12 cytokine production associated with diarrhea and weight loss as well as reduced D-xylose absorption and steatorrhea. This protocol aims to test specific anti-IL-12 therapy in this patient group. It has been previously shown that therapy targeted to IL-12 successfully treated the Th1 gut inflammation of Crohn s disease (CD). Ustekinumab, a monoclonal antibody to the p40 subunit of IL-12 and IL-23, is FDA approved for the treatment of moderate to severe plaque psoriasis, active psoriatic arthritis, and more recently, moderately to severely active CD. This protocol is designed to measure the safety of ustekinumab in patients with functional hypogammaglobulinemia and CVID enteropathy, as well as measure effects on symptoms, gut function, expression of immune cell surface markers, production of cytokines and global gene expression from blood and gut mucosal mononuclear cells, and the gut microbiota.
Patients with CVID and selective IgG subclass deficiency with gastrointestinal symptoms of malabsorption, maldigestion, and chronic diarrhea will be enrolled into this study. Subjects (up to a total of 10 individuals) will receive a treatment dose of 270 mg (3 doses of 90 mg either single-use prefilled syringe or single-use vial, depending on availability) will be injected subcutaneously in subjects by qualified nursing staff on the Day 0 study visit. Subjects will then receive a follow up treatment dose of 90 mg at Week 8, Week 16, Week 24, Week 32 and Week 40 and be followed for a total of 48 weeks.
Subjects will have study procedures prior to treatment and 48 weeks post-treatment, these include upper and/or lower endoscopies, to measure changes in immune responses and studies to evaluate physiologic measures of gut function at 48 weeks, as well as routine safety monitoring throughout the study. Gut absorption tests will be performed at the Week 24 visit. Variables will include safety (adverse event rate), clinical (weight, stool frequency, results of gut absorption tests), and laboratory (lymphocyte and cytokine assays) parameters for descriptive summary statistical analysis (n, mean, median, standard deviation, minimum and maximum range).