Interleukin-2 as anticancer immunotherapy in the age of checkpoint inhibition

Rekers and coworkers recently published their study on anti-tumor effects of recombinant interleukin-2 (IL2) and the immunoconjugate L19-IL2 with and without combined radiotherapy. Immunocompetent mice were injected with F9 teratocarcinoma cells. As soon as an average tumor volume of 200 mm³ resulted, different therapy schedules were administered including IL2, L19-IL2 and radiotherapy. Tumor growth was monitored until the tumor volume reached 4 times the volume at the start of therapy (1). This study raises the question on the role of immunotherapy with IL2 and IL2-related immunocytokines, after immunotherapy with checkpoint inhibitors has been widely established.