Figure 1.

PET-derived biodistribution in a syngeneic model of MM. Tumour-bearing mice were given 50 µg of 64Copper-labelled anti-CD38 mAbs, associated or not to 110 µg of unlabelled mAbs. With only 50 µg of 64Copper-labelled anti-CD38 mAbs, modest accumulation was observed in tumours, with no significant uptake differences between CD38− or CD38+ tumours, due to extensive accumulation of the tracer in the spleen. Adding the unlabelled mAbs dose increases tracer availability over time by “saturating” the spleen, allowing for significant increased CD38+ tumour uptake (non-parametric test). Values are expressed in percentage of the injected radioactive dose per gram of tissue and presented as mean ± SD. **: p-value ≤ 0.01; ***: p-value ≤ 0.001.