111 Real-world outcomes using pembrolizumab plus pemetrexed-platinum in 1st line metastatic NSCLC compared to results reported from KEYNOTE-189: a multicentre experience

ABSTRACT

Background: Immune checkpoint inhibitors targeting PD-1 and PD-L1 have significantly impacted treatment of Non-Small Cell Lung Cancer (NSCLC). KEYNOTE-189 demonstrated first-line pembrolizumab plus pemetrexed-platinum improves progressionfree survival (PFS) and overall survival (OS) in metastatic nonsquamous NSCLC, regardless of tumour PD-L1 expression [1]. Translating evidence from trials to real-world patient populations can be challenging as a significant proportion of patients in daily practice are often under-represented in randomised control trials due to strict inclusion and exclusion criteria. We aimed to compare real-world data with outcomes from KEYNOTE-189. Methods: We performed a retrospective analysis of 56 patients with metastatic nonsquamous NSCLC without targetable mutations, treated with first line pembrolizumab, pemetrexed and platinum. Data were collected from electronic records between October 2018 and January 2021 in 2 London cancer centres. Results: Our cohort comprised 56 patients with median age 61 years, 75% with smoking history, 59% male and 41% female. PD-L1 expression was <1% in 57% of patients. Median follow-up was 8.7 months. All patients received at least one cycle and 53% completed 4 cycles of chemoimmunotherapy. Treatment was stopped early or pemetrexed maintenance treatment was omitted due to COVID-19 in 4 patients (7%). Median PFS was 7.1 months (range 1.8 to 26.3) and median OS was 8.7 months (range 1.8 to 26.3). OS at 12 months was reached by 21 patients (38%). Adverse events were observed in 30 patients (54%), including grade 3-5 adverse events in 15 patients (27%). Conclusions: Median PFS was similar in our cohort compared to KEYNOTE-189, but not as substantial as that reported in their updated analysis. OS was lower in our cohort, however a significant proportion of our patients recently commenced treatment and had shorter duration follow-up. Safety outcomes were superior in our cohort compared to KEYNOTE-189. Disclosure No significant relationships.