Immunosuppression (IST) Can Be Safely Ceased During Chemotherapy For Post-Transplant Lymphoproliferative Disorders (PTLD) In Renal Transplant Patients

The optimal reduction of IST in renal transplant patients with PTLD is uncertain. As chemotherapy used to treat PTLD is inherently immunosuppressive, IST may be able to be stopped during this time without compromising graft function. Subsequent long-term reduction of IST is important to reduce PTLD relapse, but may increase long-term risk of graft rejection.

We performed a retrospective matched cohort study of adult renal transplant patients where IST was ceased during chemotherapy and then resumed at lower dose (calcineurin inhibitor at 50%, prednisolone <6mg daily, no third agent). Outcomes were compared to renal transplant patients without PTLD, matched for creatinine at the equivalent time post-transplant that PTLD was diagnosed in the cases, as well as age, gender, year of transplant and age at transplant. The primary endpoint of time to renal deterioration, defined as the time from PTLD diagnosis (cases) or study entry (controls) to a 25% increase in creatinine, was analysed using competing risk survival analyses. Additional endpoints were time to renal allograft failure requiring dialysis or re-transplant and overall survival.

24 cases were identified: median age at PTLD diagnosis 45yrs; 75% male; median time to onset of PTLD post-transplant was 9 years. 22 cases received CHOP-like chemotherapy and 2 received primary CNS lymphoma protocols, 7 received concurrent rituximab and 4 had consolidation radiation therapy. 88% attained complete remission. Five patients have relapsed. The 5 yr overall survival for the cases was 71% with a median follow-up of survivors of 11.9 years.

The 24 PTLD cases were compared to 84 well matched controls. There were 11 deaths in the cases and 5 in the controls. Three cases recommenced dialysis, compared to 3 controls (HR 2.5, p=0.27). The 5 yr rate of 25% increase in creatinine was 36% in cases and 20% in controls (HR 1.8, p=0.098). Of the 11 cases with ≥25% increase in creatinine, only 1 of these occurred within 6 months of IST cessation in the setting of rapidly progressive PTLD and early death. Only 2 of these 11 cases received rituximab. In contrast 5 of the 7 patients given rituximab did not develop a ≥25% deterioration in renal function.

IST can be safely ceased during chemotherapy for PTLD in renal transplant patients. Whilst long-term reduction in IST is necessary to reduce PTLD relapse, this is associated with a trend to increased risk of chronic allograft nephropathy. Prospective trials are needed to address the ideal reduction of IST in PTLD.

No relevant conflicts of interest to declare.