Biomarker and multivariate analyses results from AIPAC: A phase IIb study comparing eftilagimod alpha (a soluble LAG-3 protein) vs placebo in combination with weekly paclitaxel in HR+HER2-metastatic breast cancer
Armstrong, Anne C
De Cuypere, E.
Schroder, C. P.
AffiliationMedical Faculty, University Hospital Mannheim, Heidelberg University, Mannheim, Germany
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AbstractBackground Eftilagimod alpha (EF) is a soluble LAG-3 protein (LAG-3Ig) that binds to a subset of MHC class II molecules and mediates activation of antigen-presenting cells followed by T-cells. AIPAC investigated EF + paclitaxel (PA). We hereby report exploratory biomarker and multivariate analyses. Methods This double-blinded, 1:1 randomized phase IIb trial enrolled pts with HR+ HER2- MBC. Pts received PA (80 mg/m2 IV on D1, D8, D15) + EF (30 mg) or placebo (PL) on D2, D16 per cycle (28 days) for 24 wks + EF/PL for 52 wks. Exploratory EPs were potential biomarkers and their correlation to efficacy. Multivariate analysis used backward selection p>0.15 (univariate cox model). Blood cell subsets (CD4; CD8, PBMCs, monocytes) & Th1 biomarker CXCL-10 were measured centrally. Comparison was done using 2-sided Wilcoxon test. Results 226 pts [efti n=114; placebo n=112] were included. Pts were endocrine resistant (84%), pre-treated with CDK4/6 inhibitors (44.2%). Post-study treatment was similar. Safety/efficacy were reported at SABCS 2020 #132; SITC 2021 #948 In the multivariate predictive model 4 groups (high Neutrophil/Lymphocyte Ratio [NLR]; no prior taxanes; low monocytes and <5 yrs since diagnosis) were significant for OS (Table) On treatment mean fold-changes of monocytes (5.81 vs. 2.29; p=0.025), PBMCs (2.00 vs. 1.41; p=0.041), T cells (2.28 vs. 1.48; p=0.086), & CXCL10 (2.78 vs. 1.56; p=0.06) were significantly higher (EF vs PL) and linked to higher OS. Post baseline CD4 (median 896/μl vs. 736 μl; p=0.038) & CD8 (median 377/μl vs. 223 μl; p=0.005) T cell count increased significantly in pts with higher OS EF vs. PL. Conclusions EF + PA elicits significant effects on different immune cells which is significantly associated with higher OS. Multivariate analysis identified potential target populations for phase III.
CitationMarmé F, Wildiers H, Dirix L, Armstrong A, De Cuypere E, Dalenc F, et al. 171P Biomarker and multivariate analyses results from AIPAC: A phase IIb study comparing eftilagimod alpha (a soluble LAG-3 protein) vs placebo in combination with weekly paclitaxel in HR+ HER2- metastatic breast cancer. Vol. 33, Annals of Oncology. Elsevier BV; 2022. p. S203–4.
JournalAnnals of Oncology
TypeMeetings and Proceedings