Interferon-alpha induced changes in CEA expression in patients with CEA-producing tumours.

Enhancement of antigen expression could result in improved tumour targeting using antibodies directed to the antigen. In this study we performed radioimmunoscintigraphy using 99mTc-CEA-Scan to analyse the effect of interferon-alpha (IFN-alpha) in enhancing the expression of carcinoembryonic antigen (CEA) in ten patients with CEA-producing tumours. Furthermore, we investigated the feasibility of a future therapeutic study with this antibody fragment labelled with rhenium-186. Although IFN-alpha gave rise to a significant increase in antibody uptake by the tumour, the absolute antibody uptake in the tumour appeared to be poor, with a mean of 0.475% of injected dose (ID) in the tumour before IFN-alpha, rising to 0.562% ID in the tumour after IFN-alpha. Pharmacokinetic analysis demonstrated no significant alterations after IFN-alpha. In conclusion, the administration of IFN-alpha is an attractive way to achieve enhanced tumour targeting, although the increase was of little clinical significance in this patient population and using this antibody fragment.