Effects on Melanoma Cell Lines Suggest No Significant Risk of Melanoma Under Cladribine Treatment

Cladribine is an oral synthetic purine analog that depletes lymphocytes and induces a dose-dependent reduction of T and B cells. It was approved for the therapy of highly active relapsing-remitting multiple sclerosis. Given cladribine's mechanism of action, an increased risk of malignancies was suspected from the number of cancers that occurred in the 3.5 mg/kg-treated arm (CLARITY study). We showed that cladribine inhibits cell proliferation on three melanoma cell lines tested, irrespectively of their mutational oncogenic status and invasive/metastatic potential. Aggregated safety data demonstrated that the risk of melanoma is not confirmed.