Effect of CTLA4-Ig on severe asthma (ECSA) study ; Double blind, placebo controlled, phase IIa trial of CTLA4-Ig (abatacept) on severe asthma

INTERVENTION: CTLA4‐Ig is administered in 0, 2, 4, 8, 12, 16, and 20 wks. Placebo is administered in 0, 2, 4, 8, 12, 16, and 20 wks. CONDITION: Severe asthma PRIMARY OUTCOME: The difference in the mean FEV1 from baseline between two groups SECONDARY OUTCOME: The difference and the change in FEV1, V25, V50, FEF25‐75%, PEF and FCV from baseline.; The number of clinically significant exacerbation of asthma.; The change in the cytokine production and the proliferation of peripheral blood T‐cell.; The number of the use of rescue drug.; PEF Values in the early morning.; ACQ score. INCLUSION CRITERIA: Poor asthma control notwithstanding high‐dose inhaled steroid, defined by Japanese asthma guideline 2012. More than twice/year or once/6 months clinically significant asthma exacerbation. Meet at least one of the following criteria, ‐sputum eosinophilia more than 3%. ‐FeNO more than 50ppb. ‐peripheral blood eosinophils more than 3x108/L(last 12 months) or 1.5x108/L (observation period). ‐asthma deteriorated after 25% decrease in inhaled steroid dose. Prescribed high‐dose inhaled steroid (more than 800 microgram BDP equivalent/day) plus more than one controller. Can perform spirometry. Can keep asthma diary.