Consolidation with 90Y ibritumomab tiuxetan radioimmunotherapy in mantle cell lymphoma patients ineligible for high dose therapy: results of the phase II multicentre Polish Lymphoma Research Group trial, after 8-year long follow-up

Polish Lymphoma Research Group performed a phase-II trial to test whether ⁹⁰Y ibritumomab tiuxetan radioimmunotherapy (Y90) may constitute an alternative consolidation for mantle cell lymphoma patients unfit for high-dose therapy. Forty-six patients were consolidated with Y90 following response to the 1st (n = 34) or 2nd line (n = 12) (immuno)chemotherapy. Majority of the patients had advanced disease (stage IV and presence of B-symptoms in 85% and 70%, respectively) and high MIPI (5.8, range 4-7). Consolidation with Y90 increased the complete remission (CR) rate obtained by the 1st line therapy from 41% to 91% and allowed for median PFS of 3.3 and OS of 6.5 years. In the first relapse, CR rate increased from 16% to 75%, while median PFS and OS totaled 2.2 and 6.5 years, respectively. At 8 years, 30% of patients, consolidated in the 1st line CR were alive, without relapse. Toxicity associated with Y90 is manageable, more severe after fludarabine-based regimens.

[Hematological toxicity of radioimmunotherpy with 90Y Ibritumomab]

Radioimmunotherapy with 90Y Ibritumomabu (Zevalin, BSP) is a new method of systemic radiotherapy applicable to B-cell lymphoma patients. It may be delivered as a short outpatient procedure, with few adverse effects other than hematological toxicity. In the paper, we present length and depth of cytopenias, together with the results of additional tests performed to reveal the possible pathomechanisms, based on 102 patients treated at the University Hospital in Krakow.