Interleukin-7 (CYT107) Treatment of Idiopathic CD4 Lymphocytopenia: Expansion of CD4 T Cells (ICICLE)

Interleukin-7 (CYT107) Treatment of Idiopathic CD4 Lymphocytopenia: Expansion of CD4 T Cells (ICICLE) is a Phase I/IIa open-label, single arm clinical trial evaluating the safety profile of glycosylated recombinant human interleukin-7 (rhIL-7) as an immunostimulatory therapy in patients with idiopathic CD4 T cell lymphocytopenia (ICL) at risk of disease progression. Secondary analyses will assess the immunostimulatory effects of rhIL-7 on T cell number and function.

ICL was first characterized in the early 1990 s and is a primary immune disorder of CD4 T cell lymphocytopenia (less than 300 cells/microL or less than 20% of lymphocytes), which is not due to any known infectious process, exogenous medication, autoimmune cytopenia, or other underlying disorder associated with lymphocytopenia. ICL patients are at risk for a wide spectrum of opportunistic and other serious infections, autoimmune disorders, and other types of lymphocytopenia. At present, no validated treatment exists for ICL, and treatment is directed primarily toward infectious complications once they arise. A first-generation form of rhIL-7 was shown in pre-clinical and Phase I studies in oncology and human immunodeficiency virus (HIV)-infected patients to be well tolerated in repeated dose trials, with long-lasting increases in both CD4 and CD8 T cells. CYT107 is a second-generation rhIL-7 product made by Cytheris via a recombinant mammalian cell culture system.

DESIGN - Open-label, single-arm, Phase I/IIa interventional clinical trial. Participants will be evaluated at baseline (prior to study treatment) and according to the protocol follow-up schedule, receiving a total of 2 cycles of rhIL-7 (CYT107) during the induction phase and up to 8 cycles during the maintenance phase. Safety assessments of rhIL-7 will be the primary focus at each study visit, with secondary analyses of immune parameters, including changes from baseline in T cell number and function at Weeks 24 and 48.

DURATION - Enrollment is expected to take 3 to 4 years. Each volunteer will be followed for at least 48 weeks. Thus, total duration of the study will be approximately 5 years.

SAMPLE SIZE - Approximately 35-40 patients will be screened over a 3-year period to achieve the desired sample of 18 ICL patients, allowing for a primary safety assessment of CYT107 in this Phase I/IIa clinical trial, as well as exploring the immunomodulatory effects of rhIL-7.