MERIT study: Multicenter evaluation of prognostic factors for radioimmunotherapy

Objectives The aim of this prospective multicenter trial is to identify patient- and lesion-specific prognostic factors(PF) for RIT using yttrium-90-labeled anti-CD20 antibodies in follicular lymphoma(FL).To prove the feasibility of the multicenter web-based data collection we performed a retrospective pilot analysis.

Methods This retrospective analysis included patients from 4 German centers.Data were documented using the International RIT-Registry.PET/CT data were uploaded in pseudonymous form into an online archive designed for the purpose of this study.Treatment response was evaluated both on a patient and a lesion basis.To do so,clinical and image data were analysed for every measurable lesion in terms of location, uptake and volume.

Results Web-based data capture comprised 32 patients.Altogether,160 lesions were measured(1-25 lesions/patient).Regarding patients response,25% of patients achieved a CR,37.5% patients a PR,25% a NC and 12.5% a PD.The number of lesions per patient(p=0.009),the maximum lesion volume(p=0.004),total volume of lesions per patient(p=0.001) and FLIPI(p=0.01) were identified as PF for response(CR, PR).Concerning to lesional response, initial lesion volume and high metabolic activity were prognostically relevant(both p=0.04).Only the initial max. SUV(p<0.0001) showed an impact on lesional CR.

Conclusions The web-based multicenter acquisition of patient and image data is feasible.Based on the findings of this study,analysis of the prospective study will allow to evaluate patient- and lesion-specific PF for the RIT in FL.