Abatacept for the Treatment of Common Variable Immunodeficiency With Interstitial Lung Disease

There is no standard of care therapy for patients with granulomatous-lymphocytic interstitial lung disease (GLILD) seen in common variable immunodeficiency (CVID). Abatacept is a recombinant, human fusion protein of cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and human IgG1 that blocks T cell activation by binding to CD80 and CD86, thereby blocking CD28 engagement- the "second signal" needed for T cell activation. Abatacept has recently looked promising for the treatment of patients with complex CVID. This study is a multi-site, phase II, randomized, blinded/placebo-controlled clinical trial in pediatric subjects ≥50 kg and adult subjects (cohort 1), with an additional cohort (#2) of pediatric subjects \<50 kg tested as a single arm, receiving open-label abatacept. Cohort 1 utilizes a 'delayed-start' design to obtain maximum statistical power from this cohort. Cohort 2 will be open label due to the lack of a suitable placebo for pediatric dose abatacept syringes. A total of 21-30 evaluable subjects will be treated in cohort 1 and 8 evaluable subjects in cohort 2. Following the initial 12 months of treatment, patients will have the option of continuing abatacept for up to 3 years. Patients will have the option of continuing abatacept any time after the initial 12 months of treatment (does not have to be immediately). A separate consent form will be utilized to document a patient's decision to continue. Abatacept will be provided by BMS. Patients who decide to continue abatacept will be monitored for safety, including infections, approximately every 3 months.