Clarification of Abatacept Effects in SLE With Integrated Biologic and Clinical Approaches

Research Hypothesis: Abatacept is effective in lupus arthritis and this will be discernible in a small trial with robust endpoints which incorporates withdrawal of background immune suppressants

Study Schematic: Abatacept 125 mg or placebo will be given in a 1:1 randomization subcutaneously each week for six months. All patients may elect to continue six more months on open label Abatacept. Background Immune Suppressants will be withdrawn at any time between screening and the first dosing visit. At or after screening, patients may elect 40-160 mg depomedrol shots prn not to exceed 320 mg total up to and including the Month 2 Visit (two months after the first dosing visit) After that, additional steroids or immune suppressants, if necessary, will be allowed but the patient will be considered a non-responder in the primary endpoint at six months on that basis. At of after the 3 month visit patients with significant clinical flare may also elect to receive open label Abatacept but will be considered non-responders in the primary endpoint at six months.

Primary Objective: To compare response rates between Abatacept-Treated and Placebo-Treated Patients with active lupus arthritis in a trial designed with background immune suppressant withdrawal, limited steroid rescue, and a robust, discriminatory endpoint. The trial design and primary endpoint of response by BICLA (defined below) have been pre-tested by us for safety and ability to ensure placebo group non-response, underscoring our powering of the study. This will support a rational decision about further development of abatacept for SLE at minimal cost.

Secondary clinical outcome measures used as endpoints will include: SRI 4/5, changes in joint counts, SLEDAI, BILAG, CLASI, PGA, and LFA REAL measures.

The definitions of the clinical outcome measures are as follows: BICLA: BILAG-based Combined Lupus Assessment, This is defined as British Isles Lupus Assessment Group (BILAG) index scores that were severe at entry (BILAG A scores) improving to a moderate (BILAG B) level (or better) and all features that were moderate at entry improving to a mild level (BILAG C scores) or resolved (BILAG D scores) without increase in any other BILAG feature or SLEDAI scoring (see SLEDAI definition below), as well as no more than 10% worsening in a Physician's Global Assessment or any additional treatments after the protocolized baseline rescue (e.g. no new SLE treatments after the two month visit). SLEDAI stands for the Systemic Lupus Erythematosis Disease Activity Index. SRI 4/5 is defined as SLEDAI improvement by at least 4 points (or 5 points respectively), no increase in BILAG-measured disease activity and no more than 10% worsening in a Physician's Global Assessment (PGA). CLASI stands for the Cutaneous Lupus Erythematosus Disease Area and Severity Index. PGA stands for Physician's Global Assessment. LFA REAL stands for the Lupus Foundation of America Rapid Evaluation of the Activity of Lupus. This instrument is in a pilot phase but will be tested in the ABC study.

PK and immunogenicity studies will also be performed to help in interpretation of outcomes. Novel biologic discovery will be integrated into the clinical trial to support both pre-specified and exploratory biomarker discovery. Data will be generated that might be used to help select more appropriate patient subsets for future trials and, along with PK data, help to guide optimal dosing strategies. Optimizing patient selection and dosing are important goals for further increasing demonstrable effect size in trials by increasing the response rates in the treatment group.

This study will be performed as a double blind, randomized, placebo-controlled clinical trial with 1:1 randomization of patients to abatacept 125 mg weekly subcutaneous dose or placebo, with the withdrawal of background immune suppressants. Limited steroid rescue is allowed between the screening visit and the Month 2 visit per protocol. Additional standard of care rescue medications may be used after that as needed but will define non-response at the primary endpoint date of six months. Flaring patients may elect to receive open label abatacept at Month 3 but will also be defined as non-responders in the primary endpoint. All patients may elect to receive open label abatacept for an additional six months after the primary endpoint date, with two follow up visits (2 and 4 months post medication withdrawal) to assess withdrawal effects and to complete the safety assessments.

Accrual Goal: This study will continue to recruit until we achieve the goal of 60 patients who complete study visits through the 6 month endpoint.

Correlative Studies: Extensive exploratory protocol-specific and ancillary immune pharmacodynamic studies, focusing first on changes in IFN alpha, BLyS and other B Cell pathways. A major focus will also be on T Cell pathways with a focus on T suppressor/TH17 dichotomy after treatment with abatacept. A responder analysis will be performed in order to generate hypotheses useful for selecting appropriate patients for this treatment and optimizing dosing strategies.

Adverse Events, Serious Adverse Events and Adverse Events of special interest (infusion reactions and infections) will be collected and described. Stopping Rules: Patients may be withdrawn by the investigator for non-compliance or safety. All patients terminating before six months will be considered non responders in the primary analysis. Use of off protocol immune suppressants will not necessarily dictate withdrawal but will determine non-responder status. A DSMB board of at least two physicians (four are currently participating) will review data and may stop the study if needed.