Melanoma that has metastasised (spread beyond the initial primary tumor) is treated with Dacarbizine or Interleukin-2, also known as Proleukin, in many cases. Interleukin-2 has a response rate of up to sixteen-percent. Recent studies support the use of a new drug called Ipilimumab, which appears to prolong survival in metastatic melanoma patients. Percutaneous liver perfusion with a chemotherapeutic agent known as melphalan can prolong progression free survival in patients with melanoma metastatic to the liver, although the majority of patients in this study had melanoma starting in the eye rather than the skin.