Interleukin-2 and lanreotide in the treatment of medullary thyroid cancer: in vitro and in vivo studies.

To date no efficacious treatments are available for advanced medullary thyroid carcinoma (MTC). We investigated in vitro and in vivo a new strategy for the therapy of MTC, combining human recombinant IL-2 with lanreotide (LAN), a somatostatin analog. The in vitro effects of LAN on the sensitivity of TT cells, a MTC cell line, to IL-2-stimulated human peripheral blood mononuclear cells were determined by a lactate dehydrogenase release assay. In addition, we evaluated the toxicity, the effects on quality of life, and the antitumor activity of sc low-dose IL-2 in combination with LAN (90 mg every 28 days) in a series of 6 patients with symptomatic and advanced MTC. The cytotoxicity of IL-2-activated peripheral blood mononuclear cells was significantly increased in TT cells treated with LAN or LAN plus IL-2 compared with that in TT cells without treatment. The therapy was well tolerated, and a statistically significant improvement of quality of life was observed in patients treated with the combination of LAN and IL-2. After 6 months of therapy, partial response and stable disease have been recorded in 2 and 3 patients, respectively, with a significant decrease in calcitonin levels in 3 patients. Both in vitro and in vivo evidence suggests that the combination of LAN and IL-2 may have a role in the management of advanced and symptomatic MTC. However, these preliminary data require further validation in larger randomized trials.