Association of the Lung Immune Prognostic Index with Immunotherapy Outcomes in Mismatch Repair Deficient Tumors

SIMPLE SUMMARY: Deficient Mismatch Repair (dMMR) is an oncogenic path accounting for around 15% of cancers. It is considered as the first predictive marker of efficacy for immune checkpoint inhibitors (ICI). However, around 39% of cases are refractory and additional biomarkers are needed. The Lung Immune Prognostic Index (LIPI) is a score reflecting the host inflammation, based on lactate deshydrogenase level, and derived neutrophils to leucocytes ratio. We aimed to assess the LIPI as a prognostic factor for ICI efficacy in patients with dMMR tumors. We found that patients with a Poor LIPI were more likely to experience disease progression, fast progression (death within the first 3 months of ICI), and have shorter overall and progression free survivals. This score is a low-cost, simple, and accessible prognostic tool in dMMR that merits further investigation in prospective studies. ABSTRACT: Background: MSI-H/dMMR is considered the first predictive marker of efficacy for immune checkpoint inhibitors (ICIs). However, around 39% of cases are refractory and additional biomarkers are needed. We explored the prognostic value of pretreatment LIPI in MSI-H/dMMR patients treated with ICIs, including identification of fast-progressors. Methods: A multicenter retrospective study of patients with metastatic MSI-H/dMMR tumors treated with ICIs between April 2014 and May 2019 was performed. LIPI was calculated based on dNLR > 3 and LDH > upper limit of normal. LIPI groups were good (zero factors), intermediate (one factor) and poor (two factors). The primary endpoint was overall survival (OS), including the fast-progressor rate (OS < 3 months). Results: A total of 151 patients were analyzed, mainly female (59%), with median age 64 years, performance status (PS) 0 (42%), and sporadic dMMR status (68%). ICIs were administered as first or second-line for 59%. The most frequent tumor types were gastrointestinal (66%) and gynecologic (22%). LIPI groups were good (47%), intermediate (43%), and poor (10%). The median follow-up was 32 months. One-year OS rates were 81.0%, 67.1%, and 21.4% for good, intermediate, and poor-risk groups (p < 0.0001). After adjustment for tumor site, metastatic sites and PS, LIPI remained independently associated with OS (HR, poor-LIPI: 3.50, 95%CI: 1.46–8.40, p = 0.02. Overall, the fast-progressor rate was 16.0%, and 35.7% with poor-LIPI vs. 7.5% in the good-LIPI group (p = 0.02). Conclusions: LIPI identifies dMMR patients who do not benefit from ICI treatment, particularly fast-progressors. LIPI should be included as a stratification factor for future trials.