Additional Study Information: This is a research study of a new drug for the treatment of new onset chronic graft versus host disease (cGVHD). Chronic GVHD is a complication that can occur after a stem cell or bone marrow transplant in which the newly transplanted donor cells attack the transplant recipient's body. The current way to treat cGVHD is to use prednisone (a type of corticosteroid), but its use is limited because of its side effects. This study is being done to determine if a new drug (Ibrutinib) can help shorten the time that prednisone is needed and reduce the symptoms of cGVHD better than prednisone alone. Pharmacyclics LLC (Sponsor) is studying the effects of combining two drugs: ibrutinib and prednisone compared to placebo (sometimes called a sugar pill) and prednisone in subjects with chronic Graft Versus Host Disease (cGVHD).