Tislelizumab Plus Platinum and Etoposide Versus Placebo Plus Platinum and Etoposide as First-Line Treatment for Extensive-Stage SCLC (RATIONALE-312): A Multicenter, Double-Blind, Placebo-Controlled, Randomized, Phase 3 Clinical Trial.

INTRODUCTION: Extensive-stage SCLC (ES-SCLC) prognosis remains poor. The phase 3 RATIONALE-312 study aimed to evaluate the efficacy and safety of tislelizumab plus chemotherapy as first-line treatment for ES-SCLC. METHODS: RATIONALE-312 is a randomized, double-blind, placebo-controlled trial, conducted in the People's Republic of China. Eligible patients with previously untreated ES-SCLC were randomized 1:1 to receive four cycles of tislelizumab 200 mg or placebo, with etoposide plus carboplatin or cisplatin intravenously every 3 weeks, followed by tislelizumab 200 mg or placebo as maintenance. The primary end point was overall survival (OS). Secondary end points included progression-free survival and safety. RESULTS: Between July 22, 2019 and April 21, 2021, 457 patients were randomized to tislelizumab (n = 227) or placebo (n = 230), plus chemotherapy. Baseline demographics were generally balanced between arms. At the data cutoff (April 19, 2023), the median study follow-up was 14.2 months (interquartile range: 8.6-25.3). Tislelizumab plus chemotherapy exhibited a statistically significant OS benefit versus placebo plus chemotherapy (stratified hazard ratio = 0.75 [95% confidence interval (CI): 0.61-0.93]; one-sided p = 0.0040; median: 15.5 [95% CI: 13.5-17.1] versus 13.5 mo [95% CI: 12.1-14.9], respectively). Progression-free survival was significantly improved in the tislelizumab versus placebo arm (stratified hazard ratio = 0.64 [95% CI: 0.52-0.78]; p < 0.0001; median: 4.7 [95% CI: 4.3-5.5] versus 4.3 mo [95% CI: 4.2-4.4], respectively). Grade greater than or equal to 3 treatment-related adverse events were reported in 86% of patients in each treatment arm and were mostly hematologic. CONCLUSIONS: Tislelizumab plus chemotherapy exhibited statistically significant clinical benefit and manageable safety compared with placebo plus chemotherapy as first-line treatment in patients with advanced ES-SCLC.

Deletion of IL-27p28 induces CD8 T cell immunity against colorectal tumorigenesis.

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide, characterized by molecular and clinical heterogeneity. Interleukin (IL)-27, a heterodimeric cytokine composed of p28 and EBI3 subunits, has been reported to exert potent antitumor activity in several cancer models. However, the precise role of IL-27 in the pathogenesis of CRC remains unclear. Here, we show that during the azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced CRC development, IL-27p28 levels are dramatically increased in peripheral blood and tumor tissues, and the cytokine is mainly produced by tumor-infiltrating myeloid cells. IL-27p28 deficient mice display tumor resistances in both inflammation-associated CRC model and syngeneic MC38 colon cancer model. Administration with IL-27p28 neutralizing antibody also reduces the tumor formation in AOM/DSS-treated mice. Mechanically, CD8+ T cells in IL-27p28-/- mice exhibit enhanced tumor infiltration and cytotoxicity, which can be largely attributed to activation of the Akt/mTOR signaling pathway. Furthermore, selective depletion of CD8+ T cells in IL-27p28-/- mice markedly accelerate tumor growth and almost abrogate the protective effects of IL-27p28 deficiency. Most interestingly, the expression of IL-27p28 is also upregulated in tumor tissues of CRC patients and those with high expression of IL-27p28 tend to have a poorer overall survival. Our results suggest that loss of IL-27p28 suppresses colorectal tumorigenesis by augmenting CD8+ T cell-mediated anti-tumor immunity. Targeting IL-27p28 could be developed as a novel strategy for the treatment of colorectal cancers.