Rituximab induction response as a predictive biomarker in risk stratification in PTLD after SOT

In December, 2016, Ralf U. Trappe from the Department of Internal Medicine, DIAKO Hospital Bremen, Germany, and colleagues published the results of an international, multi-center, phase II prospective study exploring response to rituximab induction treatment as a prognostic biomarker and risk stratification method in Post-Transplant Lymphoproliferative Disorder (PTLD) after Solid Organ Transplantation (SOT). The study, published in the Journal of Clinical Oncology, recruited 152 patients with CD20⁺ PTLD in the intention to treat population.

Highlights:

• Protocol:
  • Induction: Once weekly rituximab IV (375mg/m²) for four weeks
  • CT staging for CR; if CR then low risk treatment arm, if no CR then high risk treatment arm
  • Low risk group: four cycles of IV rituximab (375mg/m²) every 21 days
  • High risk group: four cycles of R-CHOP-21 = Day 1: rituximab 375 mg/m² IV, cyclophosphamide 750 mg/m² IV, doxorubicin 50 mg/m² IV, vincristine 1.4 mg/m² (maximum, 2 mg) IV. Oral prednisone 50 mg/m² on days 1 through 5 of each cycle
• Results:
  • 25% pts (34) in low-risk group
  • ORR = 88%, CR = 70%
  • 3-year Kaplan-Meier estimate = 82%
  • Median OS = 6.6 years
  • Response to induction rituximab was a significant predictor of TTP and OR (P <0.001)
• AEs = 57 pts had grade 3 or 4 leukopenia, 52 had grade 3 or 4 infections, 12 treatment related deaths 

The authors concluded that in PTLD rituximab consolidation is better than induction alone, and that this method of treatment is feasible, effective and safe for adult patients with CD20⁺ PTLD after SOT.