Toxicity of L19-Interleukin 2 Combined with Stereotactic Body Radiation Therapy: A Phase 1 Study

PurposeThe immunocytokine L19-IL2 delivers interleukin-2 to the tumor by exploiting selective L19-dependent binding of extradomain B fibronectin on blood vessels. In preclinical models, has been shown enhance local and abscopal effects radiation therapy. The clinical safety monotherapy established previously. this study, tolerability after stereotactic body therapy (SBRT) was assessed.Methods MaterialsPatients with oligometastatic solid tumors received radical SBRT all visible metastases. Within 1 week SBRT, intravenous using a 3 + dose escalation design administered. Safety were analyzed as primary endpoint Common Terminology Criteria for Adverse Events 4.03 scoring system, progression-free overall survival secondary endpoints.ResultsA total 6 patients in 2 levels included. 15 million International Units (Mio IU) level well tolerated no dose-limiting toxicity. most frequently reported adverse events chills, noninfectious fever, fatigue, edema, erythema, pruritus, nausea/vomiting, cough dyspnea. Blood analysis revealed abnormalities liver function tests, anemia, hypoalbuminemia, hypokalemia. At second (ie, 22.5 Mio IU), which is recommended monotherapy, included experienced toxicity but recovered without sequelae. We documented long-term responders, both having non-small cell lung cancer tumor.ConclusionsBased results phase trial, combined IU. therapeutic efficacy combination currently being evaluated multicentric EU-funded ImmunoSABR. assessed. Patients endpoints. A tumor. Based