1485P - Systemic inflammatory index dynamics at 6 weeks as an early surrogate for clinical benefit in patients with NSCLC and PD-L1≥50% expression treated with pembrolizumab: Data from the real-life practice

Background

Pembrolizumab is the standard first-line treatment for patients with metastatic Non-Small Cell Lung Cancer (NSCLC) with programmed death ligand 1 (PD-L1) expression of ≥50%. However, early loss of clinical benefit is observed in many cases. There is a need to identify predictors of this phenomenon in the real-world population.

Methods

This study is a retrospective analysis of patients (pts) with stage IV NSCLC treated with pembrolizumab in routine practice, who received treatment for at least 6 weeks. Inclusion criteria included good performance status (ECOG 0-1), no active brain metastases, and no EGFR or ALK alterations. The median progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. The log-rank test and Cox regression model were used for uni- and multivariate analysis.

Results

A group of 216 pts were included. The objective response rate was 35.6%, 25.5% of pts had PD, while 11.2% of pts died before the first CT-scan. Median PFS and OS were 9.88 months (95% CI 4.85-14.92; 127 events) and 14.88 months (95% CI 9.84-19.91; 122 events), respectively. The median Systemic Inflammatory Index (SII) was 1260 in the overall population. In univariate analysis, SII >1260 had a negative impact on PFS (p=0.047) and OS (p<0.022). Tumour burden ≥111.5 mm (p<0.045) was a negative prognostic factor for OS. Other factors assessed were not relevant. An increase in the SII of more than 25% after 6 weeks of treatment correlated with a higher likelihood of early progression (p<0.001) and shorter OS (p<0.001). The differences were more pronounced in the subgroup of patients with an initial SII >1260. On multivariate analysis, higher tumour burden (HR 1.52, p=0.028, 95%CI 1.043-2.018) and an increase in SII at 6 weeks of more than 25% (HR 2.62, p<0.001;95%CI 1.625-4.234) were found to be negative prognostic factors for OS.

Conclusions

Pembrolizumab is effective in pts treated in daily practice. Taking into account additional factors, such as inflammatory index, may help to identify the optimal patient population. The dynamics of SII after 6 weeks of treatment may be a surrogate for clinical benefit.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

M. Knetki-Wroblewska: Financial Interests, Personal, Invited Speaker: Bristol Myers Squibb, Roche, MSD, Takeda, Amgen, AstraZeneca, Boehringer Ingelheim, Ipsen; Financial Interests, Personal, Advisory Board: Takeda, Boehringer Ingelheim, Bristol Myers Squibb. A. Piórek: Financial Interests, Personal, Invited Speaker: MSD, BMS, AstraZeneca, Takeda. S. Tabor: Financial Interests, Personal, Invited Speaker: MSD, BMS; Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Other, Travel grant: AstraZeneca. K. Winiarczyk: Financial Interests, Personal, Invited Speaker: BMS, Pfizer. P. Sobczuk: Financial Interests, Personal, Other, Travel grant: Novartis; Financial Interests, Personal, Other, Travel Grant: MSD, BMS; Financial Interests, Personal, Invited Speaker: Swixx BioPharma, BMS, Gilead; Financial Interests, Personal, Advisory Board: Sandoz; Financial Interests, Personal, Stocks/Shares: CelonPharma; Non-Financial Interests, Institutional, Product Samples: Immutep; Non-Financial Interests, Leadership Role, Board Member, Chair of Young Oncologists Section: Polish Society of Clinical Oncology. A. Pluzanski: Financial Interests, Personal, Invited Speaker: MSD, BMS, AstraZeneca, Roche, Pfizer; Financial Interests, Personal, Advisory Board: MSD, BMS. D.M. Kowalski: Financial Interests, Personal, Advisory Board: MSD, BMS; Financial Interests, Personal, Invited Speaker: MSD, BMS, AstraZeneca, Roche, Pfizer; Financial Interests, Personal and Institutional, Coordinating PI: MSD. M.J. Krzakowski: Financial Interests, Personal, Other, travel grant: MSD; Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Advisory Board: BMS; Financial Interests, Personal, Other, Travel grant: AstraZeneca. All other authors have declared no conflicts of interest.