Bortezomib in Patients With Chronic Graft Versus Host Disease

If improvements are seen at any dose level and patients have no DLTs, they will stay at their dose level until the end of the study. This is to avoid any possible toxicity while the patient is benefiting from their current dosing of bortezomib. If the continuous improvement in GVHD stalls at any point, or the GVHD progresses after the original improvement, while the dose level is maintained, then the dose will be increased to the next dose level. Patients will remain enrolled until exacerbation of the GVHD on increasing dose schedule or closure of the study. Clinical activity will be monitored every other week after the initiation of bortezomib until the study closes.