Abstract 5171: CD39, CD73 and CD38 as potential biomarkers for monitoring the response to mogamulizumab in Sézary syndrome
Authors: Yakymiv Yuliya , Marchisio Sara , Ortolan Erika , Pullano Verdiana , Leso Chiara , Senetta Rebecca , Marega Lorenzo , Roccuzzo Gabriele , Quaglino Pietro , Funaro Ada 
Published: March 2024

Abstract
We demonstrated aberrant expression of CD39 or CD73 and low expression of CD38 in circulating and skin-homing CD4+ T cells in patients with Sézary syndrome (SS), an erythrodermic cutaneous T-cell lymphoma (CTCL) with a leukemic component. The anti-CCR4 monoclonal antibody Mogamulizumab (Moga) has been shown to increase progression-free survival in patients with advanced SS. Here, we longitudinally explored the modulation of the expression of CD39, CD73 and CD38 in circulating CD4+ T cells from SS patients under treatment with Moga. Eight patients with relapsed/refractory SS were included in the study and prospectively followed up for two years (median duration of treatment 9,5 months, range 5-28 months). Seven out of eight (87,5%) patients showed early complete response in the blood and partial (5/7, 71,4%) or near complete response (2/7, 28,6%) in the skin. One patient (12,5%) showed no blood or skin response to the treatment. Flow cytometry analysis highlighted that the clinical response was accompanied by a rapid and remarkable increase in CD38 expression in the residual circulating CD4+ T cells, as well as in CD8+ T cells. Moreover, in six patients carrying the homozygous G/G or heterozygous A/G ENTPD1 SNP rs10748643 genotypes, permissive to CD39 overexpression in T cells, the increased CD38 expression was paralleled by rapid reduction/loss of CD39. Notably, in one patient carrying the A/A genotype, characterized by low CD39 and high CD73 expression at the baseline, response to treatment was characterized by reduction of CD73 expression. The only one patient with A/A genotype who didn’t respond to Moga showed no modulation of CD38 or CD39 expression, while CD73 expression increased. Noteworthy, Moga increases the expression of CD38 in responding patients, and influences the expression of CD39 only in patients with the permissive CD39 genotypes (G/G; A/G), but not in those with the A/A genotype. Two patients showing initial response to Moga experienced skin progression during treatment, which was associated with a significant increase of CD39 and simultaneous decrease of CD38 in residual circulating CD4+ T cells, although there was no evidence of blood relapse. These preliminary results suggest that partial or complete responses to Moga is paralleled by reduced CD39 and/or CD73 expression and increased CD38 expression. Instead, an opposite modulation of these markers is associated with disease progression hinting at the potential clinical utility of CD38, CD39 and CD73 as markers to monitor patients' response to Moga therapy.
Citation Format: Yuliya Yakymiv, Sara Marchisio, Erika Ortolan, Verdiana Pullano, Chiara Leso, Rebecca Senetta, Lorenzo Marega, Gabriele Roccuzzo, Pietro Quaglino, Ada Funaro. CD39, CD73 and CD38 as potential biomarkers for monitoring the response to mogamulizumab in Sézary syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5171.