Treatment of Unresecable and/or Metastatic Merkel Cell Carcinoma by Somatostatine Analogues

The purpose of this trial is to evaluate the efficacy of lanreotide on locally evolving and/or metastatic MCC in a national prospective multicentre phase II study (centres belonging to the skin cancer task force of the French Society of Dermatology namely "Groupe de Cancérologie Cutanée de la Société Française de Dermatologie"). This one-arm study, for which the primary endpoint is overall response to lanreotide, will follow an A'Hern plan in one step (A'Hern RP. Sample size tables for exact single-stage phase II designs. Stat Med 2001, 20:859-66) with main evaluation at 12 weeks on a population of 35 patients. The investigators make assumption that a 40% success rate at 3 months would be desirable, but if it was 20% or less the treatment would be unacceptable. It gives a trial size of 35 patients with a cut-off of 12 patients. Over 12 patients lanreotide will be considered as effective. The lanreotide treatment (Somatuline LP 120 mg injected subcutaneously every 28 days) will be provided by IPSEN Pharma laboratory. An ancillary immunohistochemistry study on somatostatine receptors 2,3,5, dopamine receptors 1,2 and polyomavirus MCPyV will bring new data on this neuroendocrine tumour and potentially provide new therapeutic perspectives. The results of this study may :

• determine whether somatostatin analogues may help to treat locally advanced and/or metastatic MCC;
• address whether there is a correlation between positive SPECT-CT (octreoscan) assessment and therapeutic response to lanreotide;
• evaluate the place of TEP-CT and SPECT-CT for MCC evaluation/staging;
• evaluate in future studies, with the ancillary data, other analogues or hybrid molecules;
• consider, if positive results are obtained from this study, somatostatin analogues as adjuvant treatment after surgery of primary MCC.