Use of pembrolizumab monotherapy for metastatic non-small cell lung cancer expressing PDL1 1-49% in the COVID-19 era


Session type:

Grace Tze-en Ding1, Findlay Thomson2, Cory Stratton2, Colin Barrie1, Kirsty Maclennan1, Sorcha Campbell1, Aisha Tufail1, Iain Phillips1, Melanie Mackean1, Mark Stares1
1Edinburgh Cancer Centre, 2University of Edinburgh



For patients with non-small cell lung cancer (NSCLC) with no activating mutations and PDL1 expression <50% pembrolizumab with platinum-based doublet chemotherapy (i.e. chemoimmunotherapy) is standard of care. In view of the potential impact of the COVID-19 pandemic on the balance of risk and benefit for patients receiving immune-suppressing chemotherapy, the Covid-19 National Cancer Medicines Advisory Group (Scotland) approved an interim treatment option of pembrolizumab monotherapy for patients with NSCLC and PDL1 expression 1-49%. We evaluated the outcomes of patients treated under this guidance at the Edinburgh Cancer Centre.


All patients with NSCLC and PDL1 expression <1-49% who commenced first-line pembrolizumab-based therapy between March 2020 and December 2020 were identified from electronic prescribing records.  Clinical details and survival outcomes were recorded. Decisions to treat with chemoimmunotherapy or pembrolizumab-monotherapy were made by consultant oncologists following clinical assessment and risk–benefit discussion with the patient.



Data were available for 36 patients: 19 (53%) chemoimmunotherapy, 17 (47%) pembrolizumab-monotherapy with a median age 70 (IQR 63-75) years. 17 patients have died;  5 (26%) on chemoimmunotherapy and 13 (76%) on pembrolizumab monotherapy. Median progression-free survival was 10.1 (95%CI 7.3-12.0) months in the chemoimmunotherapy cohort and 2.6 (95%CI 1.1-4.1) months in the pembrolizumab-monotherapy cohort (p=0.057). The minimum and median follow-up of survivors in the chemoimmunotherapy group was 5.3 and 12.3 months respectively. OS was significantly poorer in the pembrolizumab-monotherapy cohort at only 3.9 (95%CI 2.2-5.6) months, compared to not reached in the chemoimmunotherapy group (HR4.94, 95%CI 1.71-14.23 (p=0.003)). Patients in the pembrolizumab-monotherapy cohort were significantly older (median 75 (IQR 72-78) years v 64 (IQR 59-69) (p<0.001)) and had poorer performance status (P0=0%, PS1=71%, PS2=29% v PS0=21%, PS1=74%, PS2=5% (p=0.005)) than those in the chemoimmunotherapy cohort.


We provide “real-world” data for the use of single agent pembrolizumab in first line NSCLC with PDL1 expression 1-49%. showing  poor outcomes.  This likely reflects the bias selection of patients for monotherapy, felt to be at highest risk for chemotherapy complications, including those with known poor prognostic factors such as poor PS and older age. 

Impact statement

This highlights the challenging decision-making process of cancer care during the COVID-19 pandemic.