In Phase I, patients will receive intravenous PS-341 (Velcade) and 3 different dose levels of oral R115777 (Zarnestra). Dose Limiting Toxicity (DLT) will be determined over a period of one cycle and dose escalation to the next level will not occur until all patients projected at each level complete one cycle of therapy. Once DLT is determined, patients in Phase I and all patients enrolled for the phase II component will be treated at the maximum tolerated dose (MTD) to complete 8 cycles of therapy. Treatment will continue beyond 8 cycles if there is evidence of continued response. The study regimen will consist of two weeks of treatment followed by one week off for a total cycle duration of three weeks. If disease stabilization occurs (noted on 2 consecutive cycles) after the standard 8 cycles are given, treatment will be discontinued.~Patients are to be monitored for adverse events throughout the treatment phases and for a minimum of 30 days after their last dose of drugs. Follow up will include history and physical exam with laboratory evaluation at least every 3 months. Laboratories will include CMP, CBC, SPEP, UPEP, and quantitative immunoglobulins. A skeletal survey will be performed at least every 6 months.
In Phase I, patients will receive a combination of PS-341 (Velcade) and R115777 (Zarnestra) to determine the dose limiting toxicity (DLT). Once DLT is determined, patients in Phase II will be receive the maximum tolerated dose (MTD) to complete 8 cycles of therapy. Treatment will continue if there is evidence of continued response for 8 cycles. Patients will receive follow up to include normal laboratory evaluations at least every 3 months and a skeletal survey will be performed at least every 6 months.