Polycomb repressive complex 2 (PRC2) methylates histone H3 lysine 27 and represses gene expression to regulate cell proliferation and differentiation. Enhancer of zeste homolog 2 (EZH2) or its close homolog EZH1 functions as a catalytic subunit of PRC2, so there are two PRC2 complexes containing either EZH2 or EZH1. Tumorigenic functions of EZH2 and its synthetic lethality with some subunits of SWItch/Sucrose Non‐Fermentable (SWI/SNF) chromatin remodeling complexes have been observed. However, little is known about the function of EZH1 in tumorigenesis. Herein, we developed novel, orally bioavailable EZH1/2 dual inhibitors that strongly and selectively inhibited methyltransferase activity of both EZH2 and EZH1. EZH1/2 dual inhibitors suppressed trimethylation of histone H3 lysine 27 in cells more than EZH2 selective inhibitors. They also showed greater antitumor efficacy than EZH2 selective inhibitor in vitro and in vivo against diffuse large B‐cell lymphoma cells harboring gain‐of‐function mutation in EZH2. A hematological cancer panel assay indicated that EZH1/2 dual inhibitor has efficacy against some lymphomas, multiple myeloma, and leukemia with fusion genes such as MLL‐AF9,MLL‐AF4, and AML1‐ETO. A solid cancer panel assay demonstrated that some cancer cell lines are sensitive to EZH1/2 dual inhibitor in vitro and in vivo. No clear correlation was detected between sensitivity to EZH1/2 dual inhibitor and SWI/SNF mutations, with a few exceptions. Severe toxicity was not seen in rats treated with EZH1/2 dual inhibitor for 14 days at drug levels higher than those used in the antitumor study. Our results indicate the possibility of EZH1/2 dual inhibitors for clinical applications.
Although previous studies suggest that cancer cachexia is a poor prognostic factor for immune checkpoint inhibitor monotherapy, the impact of cancer cachexia on chemoimmunotherapy is unclear. We investigated the impact of cancer cachexia on the therapeutic outcomes of chemoimmunotherapy for non-small cell lung cancer (NSCLC). We retrospectively analyzed patients' medical records with NSCLC who received chemoimmunotherapy in 12 institutions in Japan between January and November 2019. We defined cancer cachexia as weight loss exceeding 5% of the total body weight or a body mass index of < 20 kg/m 2 and weight loss of more than 2% of the total body weight within 6 months before chemoimmunotherapy initiation, with laboratory results exceeding reference values. This study enrolled 235 patients with NSCLC, among whom 196 were eligible for analysis, and 50 (25.5%) met the criteria for cachexia diagnosis. Patients with cancer cachexia had a significantly higher frequency of a programmed death-ligand 1 (PD-L1) expression of ≥ 50% (48%, p = .01) and shorter progression-free survival (PFS; logrank test: p = .04) than patients without cachexia. There was no significant difference in overall survival (OS) between the cachexia and no-cachexia groups (log-rank test: p = .14). In the PD-L1 ≥ 50% population, there was no significant difference in PFS and OS (log-rank test: p = .19 and p = .79, respectively) between patients with NSCLC in the cachexia or no-cachexia groups. Cancer cachexia might be a poor prognostic factor in patients with NSCLC receiving chemoimmunotherapy.
Combination therapy with immune checkpoint inhibitors and cytotoxic chemotherapies (chemoimmunotherapy) is associated with significantly better survival outcomes than cytotoxic chemotherapies alone in patients with advanced non-small cell lung cancer (NSCLC). However, there are no prognostic markers for chemoimmunotherapy. The prognostic nutritional index (PNI) and lung immune prognostic index (LIPI) are prognostic biomarkers for immune checkpoint inhibitor (ICI) monotherapy or cytotoxic chemotherapies. Thus, we aimed to examine whether these factors could also be prognostic markers for chemoimmunotherapy. We retrospectively examined 237 patients with advanced NSCLC treated with chemoimmunotherapy. In the total group, the median overall survival (OS) was not reached, and the median progression-free survival (PFS) was 8.6 months. Multivariate analysis of OS and PFS revealed significant differences based on PNI and LIPI. Programmed cell death ligand 1 (PD-L1) was also significantly associated with OS and PFS. PNI and a PD-L1 tumor proportion score (TPS) of <50% and poor LIPI (regardless of PD-L1 TPS) were associated with poor prognosis. PNI and LIPI predicted survival outcomes in patients with advanced NSCLC treated with chemoimmunotherapy, especially in patients with PD-L1 TPS <50%. For patients in this poor category, chemoimmunotherapy may result in a worse prognosis than expected.
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