A drug used to treat melanoma and renal cell carcinoma (a type of kidney cancer) that have spread to other parts of the body. It is also being studied in the treatment of other types of cancer. Aldesleukin is a form of interleukin-2 that is made in the laboratory. Aldesleukin increases the activity and growth of T lymphocytes and B lymphocytes (types of white blood cells). This may help the immune system kill cancer cells. Aldesleukin is a type of biological response modifier. Also called Proleukin and recombinant human interleukin-2.