Early response assessment in patients with multiple myeloma during anti-angiogenic therapy using arterial spin labelling: first clinical results

To determine if arterial-spin-labelling (ASL) MRI can reliably detect early response to anti-angiogenic therapy in patients with multiple myeloma by comparison with clinical/haematological response. Nineteen consecutive patients (10 men; mean age 63.5 +/- 9.1 years) were included in the present study. Inclusion criteria were diagnosis of stage III multiple myeloma and clinical indication for therapeutical administration of bortezomib or lenalidomide. We performed MRI on 3.0T MR in the baseline setting, 3 weeks after onset of therapy and after 8 weeks. Clinical responses were determined on the basis of international uniform response criteria in correlation with haematological parameters and medium-term patient outcome. MRI studies were performed after approval by the local institutional review board. Fifteen patients responded to anti-myeloma therapy; 4/19 patients were non-responders to therapy. Mean tumour perfusion assessed by ASL-MRI in a reference lesion was 220.7 +/- 132.5 ml min(-1) 100 g(-1) at baseline, and decreased to 125.7 +/- 86.3 (134.5 +/- 150.9) ml min(-1) 100 g(-1) 3 (8) weeks after onset of therapy (P < 0.02). The mean decrease in paraproteinaemia at week 3 (8) was 52.3 +/- 47.7% (58.2 +/- 58.7%), whereas beta 2-microglobulinaemia decreased by 20.3 +/- 53.1% (23.3 +/- 57.0%). Correlation of ASL perfusion with outcome was significant (P = 0.0037). ASL tumour perfusion measurements are a valuable surrogate parameter for early assessment of response to novel anti-angiogenic therapy.