P3.CR-18 Central Nervous System Activity of Checkpoint Inihibitor in Non-Small-Cell Lung Cancer

Abstract

Data regarding the activity of atezolizumab in the central nervous system (CNS) and its toxicity in combination with radiotherapy in patients with brain metastases (BM) of non-small cell lung cancer (NSCLC) is limited. Most clinical trials adopt strict selection criteria excluding patients with active BM and the blood–brain barrier (BBB) seems responsible for limiting the distribution of agents into the CNS. Here we present a 51 yr-old female patient with the diagnosis of stage IV NSCLC with an isolated BM (T3 N3 M1b, non-mutated EGFR). She received stereotactic radiosurgery (SRS) to the isolated brain lesion (figure 1) and sequential palliative first-line systemic monotherapy with atezolizumab (1200mg/dose q21d, 15 doses). Control brain MRI 3-month post SRS showed a new lesion in the thalamus (figure 2) while on atezolizumab. Medical team decided to continue systemic treatment and the repeat brain MRI demonstrated complete response to the new lesion. Additionally, treated lesion showed evidence of pseudoprogression. While on follow-up, the patient continued to respond in the brain for 14 months. This case reports activity of atezolizumab in CNS. The advent of immunotherapy in the therapeutic algorithm of NSCLC has raised the need to identify patients that could mostly benefit from checkpoint inhibitors.