This is a Phase II, non-randomized, open-label, single-arm trial that will be conducted at up to 50 sites in North America, Europe and Australia. This study is designed to assess objective response (OR) [complete response (CR) or partial response (PR)] in subjects with cutaneous manifestations of CTCL with a requirement for maintenance of such objective response for at least 28 days in subjects with stage IIB, III, and IVA CTCL. Additionally, this study will evaluate the safety and tolerability of CTCL subjects Stages IB, IIA, IIB, III, or IVA treated with oral forodesine.