Immune escape is a prerequisite for tumor development. To avoid the immune system, tumors develop different mechanisms, including T cell exhaustion, which is characterized by expression of immune inhibitory receptors, such as PD-1, CTLA-4, Tim-3, and a progressive loss of function. The recent development of therapies targeting PD-1 and CTLA-4 have raised great interest since they induced long-lasting objective responses in patients suffering from advanced metastatic tumors. However, the regulation of PD-1 expression, and thereby of exhaustion, is unclear. VEGF-A, a proangiogenic molecule produced by the tumors, plays a key role in the development of an immunosuppressive microenvironment. We report in the present work that VEGF-A produced in the tumor microenvironment enhances expression of PD-1 and other inhibitory checkpoints involved in CD8⁺ T cell exhaustion, which could be reverted by anti-angiogenic agents targeting VEGF-A–VEGFR. In view of these results, association of anti-angiogenic molecules with immunomodulators of inhibitory checkpoints may be of particular interest in VEGF-A-producing tumors.

There currently are no internationally recognised treatment guidelines for patients with advanced gastric cancer/gastro-oesophageal junction cancer (GC/GEJC) in whom two prior lines of therapy have failed. The randomised, phase III JAVELIN Gastric 300 trial compared avelumab versus physician’s choice of chemotherapy as third-line therapy in patients with advanced GC/GEJC. Patients with unresectable, recurrent, locally advanced, or metastatic GC/GEJC were recruited at 147 sites globally. All patients were randomised to receive either avelumab 10 mg/kg by intravenous infusion every 2 weeks or physician’s choice of chemotherapy (paclitaxel 80 mg/m² on days 1, 8, and 15 or irinotecan 150 mg/m² on days 1 and 15, each of a 4-week treatment cycle); patients ineligible for chemotherapy received best supportive care. The primary end point was overall survival (OS). Secondary end points included progression-free survival (PFS), objective response rate (ORR), and safety. A total of 371 patients were randomised. The trial did not meet its primary end point of improving OS {median, 4.6 versus 5.0 months; hazard ratio (HR)=1.1 [95% confidence interval (CI) 0.9–1.4]; P = 0.81} or the secondary end points of PFS [median, 1.4 versus 2.7 months; HR=1.73 (95% CI 1.4–2.2); P > 0.99] or ORR (2.2% versus 4.3%) in the avelumab versus chemotherapy arms, respectively. Treatment-related adverse events (TRAEs) of any grade occurred in 90 patients (48.9%) and 131 patients (74.0%) in the avelumab and chemotherapy arms, respectively. Grade ≥3 TRAEs occurred in 17 patients (9.2%) in the avelumab arm and in 56 patients (31.6%) in the chemotherapy arm. Treatment of patients with GC/GEJC with single-agent avelumab in the third-line setting did not result in an improvement in OS or PFS compared with chemotherapy. Avelumab showed a more manageable safety profile than chemotherapy. ClinicalTrials.gov: NCT02625623.

While the incidence of gastric cancer has decreased worldwide in recent decades, the incidence of signet-ring cell carcinoma (SRCC) is rising. SRCC has a specific epidemiology and oncogenesis and has two forms: early gastric cancer, which can be resected endoscopically in some cases and which has a better outcome than non-SRCC, and advanced gastric cancer, which is generally thought to have a worse prognosis and lower chemosensitivity than non-SRCC. However, the prognosis of SRCC and its chemosensitivity with specific regimens are still controversial as SRCC is not specifically identified in most studies and its poor prognosis may be due to its more advanced stage. It therefore remains unclear if a specific therapeutic strategy is justified, as the benefit of perioperative chemotherapy and the value of taxane-based chemotherapy are unclear. In this review we analyze recent data on the epidemiology, oncogenesis, prognosis and specific therapeutic strategies in both early and advanced SRCC of the stomach and in hereditary diffuse gastric cancer.