Despite recent advances in treatment, a significant proportion of patients with Crohn's disease have suboptimal responses to medical therapy, leaving an urgent need to identify new therapies. One promising new approach to trea t IBD is through the manipulation of regulatory T cells (Tregs). Tregs are an immune modulating subset of CD4+ lymphocytes that antagonize the activation and effector function of multiple immune cell types and promote tolerance to self-antigens. Adoptively transferred Tregs are effective in murine models of IBD. An alternative approach to disease management through Treg manipulation is to increase Treg numbers in vivo. Interleukin-2 (IL-2, Proleukin®) is a T cell growth factor. IL-2 is currently licensed for the treatment of metastatic renal cell carcinoma and metastatic melanoma. At low doses, IL-2 promotes the selective activation and expansion of Tregs in humans. Tregs constitutively express CD25, a component of the high-affinity IL-2R, while CD25 is only transiently expressed by activated conventional T effector cells. Low-dose (LD) IL-2 selectively expands Tregs in humans and is safe in chronic GvHD and other phase 1 and 2 clinical trials.~This is a phase 1b/2a clinical trial to assess the safety and the efficacy of LD SC IL-2 for the treatment of CD utlizing daily sc LD IL-2 for 8 weeks in CD patients to determine the maximum effective dose (MED) and safety profile, and to assess a signal of efficacy. We aim to determine in CD patients whether sc LD IL-2 modulates peripheral blood and lamina propria Tregs in vivo and correlates with clinical outcome. We will perform deep immunophenotyping in CD patients treated with LD IL-2 and comprehensively assess the effects of LD IL-2 on CD4+ Tregs and other immune cells in both peripheral and mucosal compartments, and correlate changes in immune phenotype with clinical outcome. Overall this trial is designed to determine the MED and safety profile of LD IL-2 in CD, to obtain a signal of efficacy, and to assess mechanistic underpinnings.
The purpose of this study is to determine the safety and maximum effective dose (MED) of Interleukin-2 in subjects with moderate-to-severe crohn's disease.