P1.01-51 Real world Experience of Pembrolizumab in Patients with Metastatic Nonsmall Cell Lung Cancer (mNSCLC)

Abstract

Immune related adverse events (irAE) from immunotherapy in metastatic melanoma correlate with efficacy; this association is less clear in mNSCLC. We aimed to evaluate the correlation between irAE and clinical efficacy of pembrolizumab (P) in mNSCLC. All mNSCLC patients (pts) treated with P between 11/2015 to 10/2017 at BC Cancer were identified. Demographic, tumor, treatment details, and frequency and grade (Gr, CTCAE v4.0) of irAE, were collected from chart review. Kaplan-Meier curves of overall survival (OS) from initiation of P based on the development of irAE and utilizing a 6-week landmark analysis were evaluated with the log-rank test. Characteristics of cohort of 41 pts were: median age 68y (range 50-81), females 49%, non-squamous histology 81%, PD-L1 status <1%/1-49%/>50%/unknown 0/12%/83%/5%, brain metastases rate 15%, and liver metastases rate 12%. ECOG PS>1 at start of IO 32% and median Charlson Comorbidity Index (CCI) 4. P was delivered to 42% in first line setting. With a median of follow-up of 6.6 months (range: 0.7-32.3), 17 pts (41%) had died and 16 (39%) were still receiving drug. 16 pts (39%) experienced a total of 24 irAE; Gr of irAE 1/2/3/4/5: 10/12/1/1/0. The most common irAE were arthralgias (5pts), pneumonitis (4pts), and dermatitis (4pts). Treatment was temporarily held in 4pts (10%) due to irAE and permanently discontinued in 3 pts (7%). Median OS from initiation of P was 22.6 months (range: 10.6-not reached, NR). On univariate analysis, male gender (HR=3.36, 95% CI: 1.08-10.48) and ECOG>1 (HR=3.24, 95% CI: 1.13-9.35) correlated with worse OS. Median OS amongst pts requiring treatment interruption due to irAE was NR and for those treated continuously was 14.0 months. 1 pt was excluded from landmark analysis as they died within 6 week from initiation of P. Using 6 week landmark analysis, there was no significant difference in OS amongst pts who developed any irAE (median NR, 95% CI: 4.8 months-NR) compared to those who did not (14.0 months, 95% CI: 10.6-NR, log rank test p=0.84). Thyroid changes (p=0.411) and dermatitis (p=0.951) were not associated with differences in OS compared to those without irAE. Despite 32% of pts having PS>1 and a high CCI, the incidence of serious irAE was low. The impact of gender on response to P requires more study. Development of irAEs was not correlated with improved survival.