Immunologic phenotyping and S100 as biomarkers for response to anti-PD1 therapy in metastatic melanoma: A retrospective analysis

Abstract

2. Abstract Degree Project, Programme in Medicine Immunologic phenotyping and S100 as biomarkers for response to anti-PD1 therapy in metastatic melanoma: A retrospective analysis Joanna Skalenius 2018, Department of Oncology, Gothenburg, Sweden 2.1 Introduction The prognosis of metastatic melanoma has historically been poor. New treatments have improved the prognosis including the immunotherapy anti-PD1 (programmed cell-death protein1) which activates anti-tumour T-cell immune-response. However, most patients do not show complete response to anti-PD1 and toxicities are common. Therefore, research to define biomarkers to predict response is needed. Potential biomarkers that requires further investigation are T-cells and S100. 2.2 Aim To investigate different phenotypes of T-cells and S100 as predictive biomarkers for response to anti-PD1 therapy of metastatic melanoma. 2.3 Methods The study was retrospective, variables of 116patients with metastatic melanoma, who initiated anti-PD1 therapy between 1st of September 2015 to 31st August 2017 at Jubileumskliniken, Sahlgrenska University Hospital, were collected anonymized from the patient’s medical records. Variables of interest were best overall response (BOR), overall survival (OS), baseline immune panels, S100 baseline to 12weeks and S100 associated with progression. 7 2.4 Results No significant difference in OS between the different baseline T cell-phenotypes-levels analysed was found. Patients with elevated baseline S100 had a significant lower OS than patients with normal S100 (P=0.0038). 41.4% of patients had elevated baseline S100, the following analyses are done on these patients. Patients with progression had a significant different median change from baseline S100 of 143.8% compared to responding patients whose median change was -60.8% (P=0.0007). 68.8% of responding patients had decreasing values of S100 by ≥50% from baseline, 58.8% of patients with progress had increasing values of S100 by ≥50%. Patients with a >50% increase from baseline S100 had a significant lower OS than patients with a >50% decrease (P=0.0034). 2.5 Conclusions Our findings suggest that, for a proportion of patients, S100 can be a useful biomarker for response to anti-PD1 therapy of metastatic melanoma and relevant for clinicians to predict response and survival.