Analysis Of Over 100,000 Patients With Cancer For Cd274(Pd-L1) Amplification: Implications For Treatment With Immune Checkpoint Blockade.

47Background: The majority of patients with Hodgkin lymphoma have copy number alterations in the genes CD274 (PD-L1), PDCD1LG2 (PD-L2) and JAK2 (chromosome 9p24.1) resulting in high response rates to PD-1/PD-L1 blockade, even in refractory disease. The prevalence and importance of this biomarker as a predictor of response to PD-1 blockade is unknown across all solid tumors. Methods: We analyzed u003e 100,000 de-identified patient samples from the Foundation Medicine database and 2,039 clinically annotated patients from UCSD. CD274 amplification was called for copy number alterations (CNAs) ≥ 6. PFS was calculated by KM analysis. Results: Altogether, 0.7% of all tumors types had ≥ 6 CNAs in CD274 (Table). CD274 CNAs were identified in 121 tumor histologies. 13 patients at UCSD were found to have CD274 amplification of which nine were treated with PD-1/PD-L1 blockade (either alone or in combination with another immunotherapeutic or targeted therapy) after a median of four prior systemic therapies. The response ...