Real-world Outcomes With Rituximab-based Therapy for Posttransplant Lymphoproliferative Disease Arising After Solid Organ Transplant.

BACKGROUND Optimal upfront therapy for posttransplant lymphoproliferative disease (PTLD) arising after solid organ transplant remains contentious. Rituximab monotherapy (R-Mono) in unselected patients has shown a lack of durable remissions. CHOP-based chemotherapy confers improved response rates, although concerns exist about toxicity. METHODS This multicenter retrospective study reports outcomes for adults with biopsy-proven B-cell PTLD treated initially with R-Mono or R-CHOP. Selection of therapy was made according to physician preference. RESULTS Amongst 101 patients, 41 received R-Mono and 60 had R-CHOP. Most (93%) had undergone renal or liver transplantation. R-CHOP showed a trend toward improved complete (53% vs. 71%; P=0.066) and overall (75% vs. 90%; P=0.054) response rates. In the R-Mono group 13/41 (32%) subsequently received chemotherapy, whilst 25/41 (61%) remained progression-free without further therapy. With median follow-up of 47 months, overall survival (OS) was similar for R-Mono and R-CHOP, with 3-year OS of 71% and 63% respectively (P=0.722). Non-PTLD mortality was 3/41 (7%) and 4/60 (7%) within 12 months of R-Mono or R-CHOP respectively. The international prognostic index was statistically significant, with low- (0-2 points) and high-risk (≥3 points) groups exhibiting 3-year OS of 78% and 54% respectively (P=0.0003). In low-risk PTLD, outcomes were similar between therapies. However, in high-risk disease R-Mono conferred an inferior complete response rate (21% vs. 68%; P=0.006), albeit with no impact on survival. CONCLUSION Our data support R-Mono as initial therapy for PTLD arising after renal or liver transplantation. However, upfront R-CHOP may benefit selected high-risk cases in whom rapid attainment of response is desirable