Rituximab therapy is effective for posttransplant lymphoproliferative disorders after solid organ transplantation: Results of a phase II trial

BACKGROUND. Posttransplant lymphoproliferative disorders (PTLD) remain an uncommon complication of solid organ transplantation with a high mortality rate reported after conventional therapies. Alternative treatments such as rituximab have been explored. METHODS. Eleven patients with PTLD, who were CD20 positive, received an intravenous dose of rituximab, 375 mg/m², weekly × 4 weeks, repeated every 6 months for 2 years in responding patients. The median age of the patients was 56 years (range, 43-68 yrs), and 9 patients were male. The type of solid organ transplantation that these patients received included lung (five patients), kidney (four patients), heart (one patient), and kidney/pancreas (one patient). The median time from transplantation to a PTLD diagnosis was 9 months (range, 1-122 mos). Diagnostic B-cell histology was diffuse large cell lymphoma or polymorphous process. No patient had bone marrow or central nervous system involvement. Primary extranodal disease was noted in 82% of patients. Immunosuppressive therapy was decreased at the time of diagnosis. RESULTS. Rituximab was well tolerated, with mild infusional blood pressure alterations noted in two patients. The median follow-up period was 10 months (range, 1-32 mos). The overall response rate was 64%, with 6 complete responses (CR), 1 partial response, 2 cases of progressive disease, and 2 deaths. The median duration of CR was 8 months (range, 2-19+ mos). The median time to treatment failure was 10 months (range, 5-25+ mos). The median survival was 14 months (range, < 1-32+ mos). Four patients were alive at the time of last follow-up. CONCLUSIONS. Single-agent rituximab may offer a response and survival advan-tage in patients with PTLD. Further evaluation of rituximab in these disorders, potentially in combination with other therapies, is warranted.