2019P - Analysis of lung immune prognostic index (LIPI) score in a small cell lung cancer carcinoma (SCLC) cohort, supporting its prognostic use and investigating its predictive potential

Background

Current standard-of-care treatment for extensive-stage SCLC involves combining chemotherapy with immune checkpoint inhibitors (ICI). However, appropriate predictive biomarkers are still lacking. The LIPI is a clinical tool developed in non-small cell lung cancer. We aim to study whether the LIPI score can be a prognostic and predictive tool in SCLC.

Methods

We conducted a retrospective unicenter observational study. 48 patients were included, classified in cohort ICI when treated with carboplatin-etoposide and atezolizumab (n=23); and cohort CT when treated with cisplatin/carboplatin-etoposide (n=25). Complete blood cell counts and LDH levels were measured before treatment. LIPI score was calculated and patients were classified in good (0), intermediate (1) and poor categories (2). Primary outcomes were to determine progression-free survival (PFS) and overall survival (OS) in both cohorts stratified by LIPI categories. Fischer’s test was used for categorical data; while PFS and OS were evaluated by Kaplan-Meir.

Results

Cohorts were comparable without significant differences in baseline characteristics (age, sex, metastatic sites, corticoid use). Regarding PFS, at 12 months all patients in the CT cohort had progressed, versus 79% in the ICI cohort. PFS was better for LIPI 0 with statistical significant difference (p=0.043) with 22% free of progression at 12 months, versus 6% for LIPI 1 and 0% for LIPI 2. For the ICI cohort PFS was significantly better for LIPI 0 as well (p=0.0151), with 40% free of progression at 12 months. The one-year OS survival rate was 40% for the CT cohort and 32% for the ICI cohort. Although no statistical significance was found, a trend towards better OS for LIPI 0 was seen in both cohorts; with 67% alive at 1-year versus 23% for LIPI 1 and 34% for LIPI 2. This was also present in the ICI cohort with 60% alive at 1-year for LIPI 0 versus 27% for LIPI 1 and 0% for LIPI 2.

Conclusions

Although limited by the small number of patients and the shorter follow-up in the ICI cohort, our study supports LIPI score can be a prognostic tool in SCLC. Further studies are needed to find whether it could also be a predictive tool for response to ICI in SCLC.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Hospital Universitario Fundación Alcorcón.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.