Bortezomib for the Treatment of Refractory Chronic Graft-vs-Host Disease(cGVHD)

Inclusion Criteria: Each patient must meet all of the following inclusion criteria to be enrolled in the study: * Voluntary written informed consent before performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care. * ≥18 years old. * Able to understand and sign informed consent. * Diagnosis of steroid-refractory cGVHD is defined as either failure to improve after 2 months or progression after 1 month of standard steroid based therapy. * No previous treatment with Bortezomib for cGVHD * ECOG PS\<3 * Total Bilirubin ≤ 1.5x ULN * Life expectancy \> 3months. * Female subject is either post-menopausal or surgically sterilized or willing to use an acceptable method of birth control for the duration of the study and through a minimum of 30 days after the last dose of bortezomib. * Male subject agrees to use an acceptable method for contraception for the duration of the study and through a minimum of 30 days after the last dose of study drug. Exclusion Criteria: Patients meeting any of the following exclusion criteria are not to be enrolled in the study. * Patient has a platelet count of \<50x 10\^9/L within 14 days before enrollment. * Patient has an absolute neutrophil count of \<1.0 x 10\^9/L within 14 days before enrollment. * Patient has a calculated or measured creatinine clearance of \<30 mL/minute within 14 days before enrollment. * Patients with Total Bilirubin \> 1.5x ULN * Patient has ≥ Grade 2 peripheral neuropathy within 14 days before enrollment. * Myocardial infarction within 6 months prior to enrollment or has New York Heart Association (NYHA) Class III or IV heart failure (see section 8.4), uncontrolled angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic evidence of acute ischemia or active conduction system abnormalities. Prior to study entry, any ECG abnormality at Screening has to be documented by the investigator as not medically relevant. * Patient has hypersensitivity to bortezomib, boron or mannitol. * Female subject is pregnant or breast-feeding. Confirmation that the subject is not pregnant must be established by a negative serum β-human chorionic gonadotropin (β-hCG) pregnancy test result obtained during screening. Pregnancy testing is not required for post-menopausal or surgically sterilized women. * Patient has received other investigational drugs with 14 days before enrollment * Serious medical or psychiatric illness likely to interfere with participation in this clinical study. * Primary malignancy (for which the transplant was received ) not in remission * Diagnosed or treated for another malignancy within 3 years of enrollment, with the exception of complete resection of basal cell carcinoma or squamous cell carcinoma of the skin, an in situ malignancy, or low-risk prostate cancer after curative therapy. * Radiation therapy within 3 weeks before randomization. Enrollment of subjects who require concurrent radiotherapy (which must be localized in its field size) should be deferred until the radiotherapy is completed and 3 weeks have elapsed since the last date of therapy.