Allogeneic hematopoietic stem cell transplantation with a reduced-intensity conditioning regimen for treatment of metastatic renal cell carcinoma: single institution experience with a minimum 1-year follow-up

Objective The aim of this study was to evaluate the safety and efficacy of allogeneic hematopoietic stem cell transplantation with a reduced-intensity conditioning regimen (RIST) for interferon-α–refractory metastatic renal cell carcinoma (RCC). Patients and methods Of 26 patients referred to the National Cancer Center Hospital for possible RIST between June 2000 and April 2002, an HLA-identical relative was identified for 12 patients. Nine patients underwent RIST. The conditioning regimen consisted of fludarabine 180 mg/m2 or cladribine 0.66 mg/kg, plus busulfan 8 mg/kg and rabbit antithymocyte globulin 5 mg/kg. Graft-vs-host disease (GVHD) prophylaxis was cyclosporine alone. Results All patients achieved engraftment without grade III to IV nonhematologic regimen-related toxicity. All patients achieved complete donor-type chimerism without donor lymphocyte infusion by day 60. Four patients developed acute GVHD, and four developed chronic GVHD. One patient (11%) achieved partial response. As of July 2003, six patients were alive at median follow-up of 681 days. The actuarial overall survival rate was 89% at 1 year and 74% at 2 years. The overall survival rate tended to be higher in the 12 patients with a matched donor than in the other 14 patients without a matched donor (p = 0.088). Conclusion Our RIST procedure is feasible without severe toxicity. The efficacy of RIST for RCC should be confirmed in phase II/III clinical trials.