Predicting Response to Immunotargeted Therapy in Endometrial Cancer via Tumor Immune Microenvironment: A Multicenter, Observational Study

Only one-third of patients with advanced MSS/pMMR endometrial cancer exhibit a lasting response to the combination treatment of Pembrolizumab and Lenvatinib. The combined administration of these two drugs is based on Lenvatinib's ability to modulate the tumor microenvironment, enabling Pembrolizumab to exert its effect. These findings underscore the importance of exploring tumor microenvironment parameters to identify markers that can accurately select candidates for this type of therapy. An open non-randomized observational association study was conducted at six clinical centers, involving a total of 28 patients with advanced MSS/pMMR endometrial cancer who received Pembrolizumab and Lenvatinib therapy. Using TSA-associated multiplex immunofluorescence, we analyzed the proportion of CD8+ T lymphocytes, CD20+ B lymphocytes, FoxP3+ T regulatory lymphocytes, and CD163+ macrophages in tumor samples prior to immunotargeted therapy. The percentage of CD20+ B lymphocytes and the CD8-to-CD20 lymphocytes ratio was significantly higher in patients who responded to treatment compared to non-responders (responders vs. non-responders: 0.24 (0.1-1.24)% vs. 0.08 (0.00-0.15)%, p = 0.0114; 1.44 (0.58-2.70) arb. unit vs. 19.00 (3.80-34.78) arb. unit, p = 0.0031). The sensitivity and specificity of these biomarkers were 85.71% and 70.59%, and 85.71% and 85.71%, respectively. The proportion of CD20+ B lymphocytes and the CD8-to-CD20 lymphocytes ratio in the stroma of endometrial cancer serves as both a prognostic marker of response to immunotargeted therapy and a prognostic factor for progression-free survival in patients.

ADAM: A multicenter, non-interventional, prospective cohort study for determination of prevalence of homologous recombination repair genes mutations (HRRm) in metastatic castrate-resistant prostate cancer (mCRPC)—Interim analysis

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Background: The HRRm detection is used to prescribe PARP inhibitors in mCRPC patients. The frequency of HRR alterations has been investigated in several clinical studies, but the prevalence of HRRm in real clinical practice remains unclear. We conducted the first study to evaluate prevalence of HRRm in mCRPC patients in Russia. This interim analysis is aimed to provide HRRm rate in real practice in Russian population. Methods: Patients with mCRPC and available tumor tissue samples (FFPEs) were enrolled from October 2020 till May 2021. Samples were analyzed in 3 labs. Target enrichment using multiplex PCR and library preparation of genes involved in HRR (BRCA2, BRCA1, RAD54L, FANCL, BARD1, ATM, CHEK1, RAD51B, PALB2, RAD51D, CDK12, RAD51C, BRIP1, CHEK2) was performed using three different techniques: GeneReader NGS System (QIAGEN), KAPA HyperPlus and SeqCap EZ Choice (Roche) and in-house targeted NGS-panel. For last 2 sequencing was performed using MiSeq (Illumina). Results: In this interim analysis we included 331 mCRPC patients from 20 sites with median age 67 years, 86,7% caucasian. Family or personal history of oncological diseases had 66 (20%) of pts 300 FFPEs were analyzed by NGS, 31 (9%) were not valid (poor quality/not enough DNA). HRRm rate is 19,7% (59/300). Most frequently mutated genes ( > 1%) listed in the table below. Other mutations (RAD51B, RAD51C, BARD1, FANCL, RAD51D, RAD54L) were detected in 1-2 cases per gene. Conclusions: This first systematic analysis of HRRm in Russian population of mCRPC patients showed general consistency with previously reported HRRm data (19,7% in our trial in comparison with 27.9% in PROfound trial). Lab approach using different techniques in real practice has to be established.[Table: see text]