EP2 and EP4 blockade prevents tumor-induced suppressive features in human monocytic myeloid-derived suppressor cells.

Tumors educate their environment to prime the occurrence of suppressive cell subsets, which enable tumor evasion and favors tumor progression. Among these, there are the myeloid-derived suppressor cells (MDSCs), their presence being associated with the poor clinical outcome of cancer patients. Tumor-derived prostaglandin E2 (PGE2) is known to mediate MDSC differentiation and the acquisition of pro-tumor features. In myeloid cells, PGE2 signaling is mediated via E-prostanoid receptor type 2 (EP2) and EP4. Although the suppressive role of PGE2 is well established in MDSCs, the role of EP2/4 on human MDSCs or whether EP2/4 modulation can prevent MDSCs suppressive features upon exposure to tumor-derived PGE2 is poorly defined. In this study, using an in vitro model of human monocytic-MDSCs (M-MDSCs) we demonstrate that EP2 and EP4 signaling contribute to the induction of a pro-tumor phenotype and function on M-MDSCs. PGE2 signaling via EP2 and EP4 boosted M-MDSC ability to suppress T and NK cell responses. Combined EP2/4 blockade on M-MDSCs during PGE2 exposure prevented the occurrence of these suppressive features. Additionally, EP2/4 blockade attenuated the suppressive phenotype of M-MDSCs in a 3D coculture with colorectal cancer patient-derived organoids. Together, these results identify the role of tumor-derived PGE2 signaling via EP2 and EP4 in this human M-MDSC model, supporting the therapeutic value of targeting PGE2-EP2/4 axis in M-MDSCs to alleviate immunosuppression and facilitate the development of anti-tumor immunity.

Preliminary data from a 4-year mirror-image and multicentre study of patients initiating paliperidone palmitate 6-monthly long-acting injectable antipsychotic: the Paliperidone 2 per Year study.

Background: Paliperidone palmitate 6-monthly (PP6M) is the first long-acting antipsychotic injectable (LAI) to allow for only two medication administrations per year, though there is presently limited insight into its effectiveness and potential added value in real clinical practice conditions. Objectives: To present our ongoing study and draw its preliminary data on patient characteristics initiating PP6M and adherence during the first year of treatment. Methods: The paliperidone 2 per year (P2Y) study is a 4-year, multicentre, prospective mirror-image pragmatic study taking place at over 20 different sites in Europe. The mirror period covers 2 years either side of the PP6M LAI initiation. Retrospective data for the previous 2 years are collected for each patient from the electronic health records. Prospective data are recorded at baseline, 6, 12, 18 and 24 months of drug administration and also cover information on concomitant psychiatric medication, relapses, hospital admissions, side effects, discontinuation and its reasons. Meanwhile, here we present preliminary data from the P2Y study at basal and 6-month period (first and second PP6M administration). Results: At the point of PP6M initiation, the most frequent diagnosis was schizophrenia (69%), the clinical global impression scale mean score was 3.5 (moderately markedly ill) and the rate of previous hospital admissions per patient and year was 0.21. PP6M was initiated after a median of 3-4 years on previous treatment: 146 (73%) from paliperidone palmitate 3-monthly, 37 (19%) from paliperidone palmitate 1-monthly and 17 (9%) from other antipsychotics. The mean dose of the first PP6M was 1098.9 mg. The retention rate at 6 months and 1 year of treatment on PP6M in our cohort was 94%. Conclusion: Patient and clinician preference for LAIs with longer dosing intervals was the main reason for PP6M initiation/switching resulting in high treatment persistence. Future data are needed to evaluate the full impact of PP6M in clinical practice.