926P - UK national real-world outcome data of first-line pembrolizumab treatment in head and neck squamous cell cancer (HNSCC)

Background

Immunotherapy has significantly improved survival in patients with several solid tumours including head and neck squamous cell carcinoma (HNSCC). Pembrolizumab received approval in the UK in 2020 as first-line treatment for recurrent or metastatic (R/M) HNSCC based on KEYNOTE-048 trial data which demonstrated an extended overall survival (OS) when compared to the EXTREME chemotherapy regime in patients with R/M HNSCC tumours with a combined positive score (CPS)≥1 (Burtness, 2019). Here we, provide real-world data on the clinical outcomes of the use of pembrolizumab as first-line systemic treatment for HNSCC in the United Kingdom (UK).

Methods

Retrospective data analysis of patients with HNSCC treated with pembrolizumab as first-line treatment across 18 centres in UK from 20/03/20 to 31/05/2021.

Results

211 patients were included; the median age was 66.0 (range=39-88.1), 73.0% of patients were male and >65% of patients had a smoking history or alcohol history. In addition to patients with R/M HNSCC, 47 patients had locally advanced disease deemed not suitable for curative treatment at diagnosis; a group of patients not included in KEYNOTE-048. Analysis showed an overall response rate (ORR) of 24.7%, median progression free survival (PFS) of 4.8 months (95% confidence interval [CI]: 3.6-6.1) and median OS of 10.8 months (95% CI 9.0-12.5). 53 patients proceeded to second line treatment and the median PFS2 was 10.2 months (95% CI: 8.8-11.5), similar to PFS2 of 10.3 months for those with CPS≥1 in KEYNOTE-048. The treatment was well-tolerated and only 18 patients (8.5%) stopped pembrolizumab due to an immune-related toxicity (IRT). Moreover, patients with a documented IRT had a statistically significant longer median PFS (11.3 vs 3.3 months; log-rank p-value=<0.001) and median OS (18.8 vs 8.9 months; log-rank p-value <0.001) compared to the groups of patients with no documented IRT.

Conclusions

In this real-world retrospective cohort, we have shown a similar ORR, longer PFS, similar PFS2 and a shorter OS compared to the results of KEYNOTE-48. Those with locally advanced disease deemed not suitable for curative treatment at diagnosis had similar ORR, PFS and OS compared to patients with recurrent or metastatic disease.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

A. Haridass: Non-Financial Interests, Personal, Invited Speaker: MSD. P. Jankowska: Non-Financial Interests, Personal, Speaker, Consultant, Advisor: MSD, BMS, AstraZeneca. R. Moleron: Non-Financial Interests, Advisory Board: MSD, Vasodynamics. A. Kong: Non-Financial Interests, Personal, Advisory Board: MSD; Non-Financial Interests, Institutional, Research Funding: AstraZeneca, PUMA; Non-Financial Interests, Personal, Invited Speaker: Merck, BMS; Non-Financial Interests, Personal, Advisory Role: Avinnity. All other authors have declared no conflicts of interest.