1048PD - RetroSpective cohort stUdy of PD-L1 expression in REcurrent and/or MEtastatic squamous cell carcinoma of the head and neck (SUPREME-HN)

Abstract

Background: Clinically meaningful antitumour activity and improved overall survival (OS) in recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) have been achieved by targeting the PD-1/PD-L1 axis. Tumoral PD-L1 expression correlates with response to blocking PD-1/PD-L1 antibodies. In a retrospective study, we investigated tumoral PD-L1 expression as a prognostic biomarker in R/M HNSCC patients (pts) treated with standard of care (SOC) therapy. Methods: Archival tumor samples from R/M HNSCC pts diagnosed between March 2011 and June 2015 at 19 institutions in 7 countries were evaluated for PD-L1 expression using the validated Ventana SP263 assay and scored as PD-L1 high (≥25% of tumor cells [TC]) or low/negative (<25% of TC). Clinical-demographic data, including treatment patterns and outcomes, were extracted from medical records. Descriptive analyses were conducted and survival estimated by the Kaplan-Meier method. Progression-free survival (PFS) was defined from start of first- (1L) or second-line (2L) therapy to time of progression (on/after therapy) or death due to any cause. OS was defined from diagnosis index date of R/M disease to time of death. The Cox proportional hazards model was applied. Results: The final dataset included 412 pts. Median age was 62.0 years (range 28.0–93.0); 79.9% were male and 88.2% white. PD-L1 expression was high in 132 (32.0%), low/negative in 264 (64.1%), unknown in 16 (3.9%). Median OS (8.2 vs 10.1 months; P = 0.55) and PFS from the start of 1L chemotherapy (4.2 vs 4.8 months; P = 0.37) did not significantly differ between PD-L1 high and low/negative pts, respectively. Median PFS following 2L chemotherapy was statistically significantly longer in PD-L1 high versus low/negative pts (4.1 vs 2.2 months; P = 0.04). PD-L1 status was not statistically significant in multivariate analyses of OS (P = 0.74) or PFS following 1L chemotherapy (P = 0.63); however, there was a trend for improved PFS following 2L chemotherapy (P = 0.09). Conclusions: Tumoral PD-L1 expression was not significantly associated with OS or PFS following 1L SOC chemotherapy; however, it was associated with prolonged PFS following 2L SOC chemotherapy. Clinical trial identification: NCT02543476 (August 25, 2015) Legal entity responsible for the study: AstraZeneca PLC Funding: AstraZeneca PLC Disclosure: S. Pai: Corporate sponsored research (Abbvie, AstraZeneca, Oncosec, Tesaro), Consultant (Abbvie, AstraZeneca, Merck, Oncosec) Investigator-initiated studies (AstraZeneca, Merck) Speaker at IO drug launches for HN cancer in an international country (Merck). E.E. Cohen: Consultant (Eisai; Pfizer; Merck; AstraZeneca; Bristol-Myers Squibb; Human Longevity(HLI)). D. Lin: Corporate sponsored research (Abbvie, Tesaro, AstraZaneca). G. Fountzilas: Consultant (Pfizer, Sanofi, Roche) Stock shareholder (ARIAD (an immediate family member)) Honoraria (AstraZeneca). E.S. Kim: Consultant (Celgene, Boehringer Ingelheim, Eli Lilly, AstraZeneca). N. Baste: Corporate sponsored research (AstraZeneca) Consultant (Bristol-Myers Squibb, MSD, Merck Serono) D. Clayburgh: Corporate sponsored research (Abbvie & AstraZeneca. N. Shara: Honoraria (NIH-reviewer) Full-time/part-time employee (MedStar Health Research Institute) J. Zhang: Consultant (AztraZeneca & Boehringer Ingelheim). M. Stokes: Employment (Evidera) and research funding (Evidera). D. Lawrence: Full time employee of AstraZeneca UK. A. Khaliq, G. Melillo, N. Shire: Employee and Shareholder (AstraZeneca). All other authors have declared no conflicts of interest.