Boehringer’s ONCEPT IL-2 (feline interleukin-2 recombinant canarypox virus (vCP1338)) is a veterinary medicine used in combination with surgery and radiotherapy to treat cats with fibrosarcoma, an aggressive soft-tissue tumor. Reduces the risk of relapse. Stimulates the cat’s immune system to attack the cancer cells. Injected subcutaneously around the site of the surgically removed tumor in a course of six doses.