1057PDFINAL RESULTS FROM A CANCER RESEARCH UK FIRST IN MAN PHASE I TRIAL OF IMA950 (A NOVEL MULTI PEPTIDE VACCINE) PLUS GM-CSF IN PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA

ABSTRACT Background IMA950 is a novel multi-peptide glioblastoma (GBM) specific vaccine that contains 11 HLA binding tumour associated peptides (TUMAPs), identified on human leukocyte antigen (HLA) surface receptors in primary human GBM tissue, and one viral (HBV) marker peptide. The TUMAPs are designed to activate TUMAP-specific CD8+ cytotoxic and CD4+ helper T lymphocytes, which then recognise cognate TUMAPs presented by GBM tumour cells and effect a targeted immune response. Methods Patients (pts) must be eligible for standard treatment of newly diagnosed GBM (maximal safe tumour resection, concomitant chemoradiotherapy (CRT) and adjuvant temozolomide (TMZ)) and be HLA-A*02 positive with no history of autoimmune disease. Vaccination comprises IMA950 plus GM-CSF injected intradermally at 11 time points over a 24 week period. Up to 45 pts will be entered into one of two cohorts with similar schedules. In Cohort 1 vaccination begins 7 to 14 days prior to initial CRT; in Cohort 2 it begins at least 7 days post CRT and 28 days prior to adjuvant TMZ. Safety is assessed according to NCI CTCAE Version 4.0. Immune response is determined by HLA-multimer analysis of vaccine-induced Tcell response in PBMC samples. Secondary objectives include observation of any anti-tumour effects, measurement of pre-treatment regulatory T-cell levels and evaluation of the effect of steroid dose on observed T-cell responses. Results As of 21 May-12, 25 pts (12 in Cohort 1 and 13 in Cohort 2) have been recruited. Adverse events related to either IMA950 or GM-CSF have been restricted to minor injection site reactions, a single distant allergic rash and a case of isolated asymptomatic neutropenia. Eleven pts have been analysed for immune response with 10 being evaluable (6 from Cohort 1 and 4 from Cohort 2). Eight pts responded to the HBV marker peptide, 8 pts to at least one TUMAP and 4 pts to multiple TUMAPs; 100% of pts in Cohort 2 responded to at least one TUMAP and 50% to multiple TUMAPs. Conclusion IMA950 plus GMCSF given alongside standard treatment for GBM has been well tolerated to date and these results already give encouragement for further development of this vaccine. Disclosure H. Singh-Jasuja: Harpreet Singh-Jasuja is a Founder and the Chief Scientific Officer of Immatics Biotechnologies GmbH. He also has stock or ownership stakes to disclose. All other authors have declared no conflicts of interest.