Systemic treatment of advanced esophageal squamous cell carcinoma (ESCC) mainly consists of cytotoxic agents, aiming to palliate symptoms and prolong survival. Cisplatin and 5-fluorouracil have been considered standard treatment for several decades. Efforts to develop more effective treatment have led to clinical trials testing triplet, irinotecan-based, oxaliplatin-based and paclitaxel-based regimens. Molecular-targeting agents, mainly anti-EGFR inhibitors including gefitinib, panitumumab and nimotuzumab, have been investigated; however, no molecular-targeting agents demonstrate the clinical utility in Phase 3 trials so far. Negative results from Phase 3 trials testing gefitinib and panitumumab suggest the importance of identifying predictive biomarkers of responses to molecular-targeting agents. On the basis of results from Phase 3 trials testing PD-1 inhibitors, nivolumab and pembrolizumab, are anticipated to be the standard treatment for patients with ESCC. Dual immune checkpoint inhibition and immunotherapy in combination with cytotoxic agents are under study. Recent advances in next-generation sequencing technologies provide comprehensive catalogues of genetic alterations in ESCC which may lead to therapeutic breakthroughs in a personalized manner. Here, we review the existing clinical data and discuss future perspectives with a focus on the systemic treatment of advanced ESCC.

Immunotherapy, especially immune checkpoint inhibitors, has revolutionized the standard-of-care of multiple types of tumors. For colorectal cancer, the clinical development of immune checkpoint inhibitors is mainly separated according to the status of microsatellite instability or mismatch repair in a tumor. High-level microsatellite instability/deficient mismatch repair metastatic colorectal cancer generally has a tumor microenvironment with infiltration of T cells, associated with a favorable response to immune checkpoint inhibitors. Immune checkpoint inhibitors, including pembrolizumab (anti-PD-1 inhibitor) and nivolumab (anti-PD-1 inhibitor) with or without ipilimumab (anti-CTLA-4 inhibitor), have been integrated into the standard-of-care for high-level microsatellite instability/deficient mismatch repair metastatic colorectal cancer. Conversely, limited T-cell infiltration in the tumor microenvironment of microsatellite stable/proficient mismatch repair metastatic colorectal cancer, which constitutes the majority of metastatic colorectal cancer, is assumed to be a major resistant mechanism to immune checkpoint inhibitors. Currently, clinical trials to improve the clinical activity of immune checkpoint inhibitors by immunomodulation are ongoing for metastatic colorectal cancer. Furthermore, immune checkpoint inhibitors are under development in neoadjuvant and/or adjuvant setting. Here, we review the existing clinical data with ongoing trials and discuss the future perspectives with a focus on the immunotherapy of colorectal cancer.

PURPOSE: Microsatellite instability–high (MSI-H) advanced gastric or esophagogastric junction cancer (AGC), accounting for 5%-6% of all AGC cases, has shown an enhanced responsiveness to immunotherapy. We performed a single-arm phase II study to evaluate the combination of nivolumab (NIVO) and low-dose (LD) ipilimumab (IPI) for first-line treatment of MSI-H AGC. PATIENTS AND METHODS: Patients with MSI-H AGC received NIVO (240 mg once every 2 weeks) and IPI (1 mg/kg once every 6 weeks). The primary end point was overall response rate (ORR) assessed by blinded independent central review. Secondary end points included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), safety, and biomarker analysis. MSI-H status was confirmed with an MSI-IVD Kit (Falco). RESULTS: Twenty-nine patients were enrolled. The ORR was 62.1% (95% CI, 42.3 to 79.3), with a complete response rate of 10.3%. The DCR was 79.3% (95% CI, 60.3 to 92.0). Treatment-related adverse events (TRAEs) of any grade occurred in 93.1% of patients, with those of grade ≥3 manifesting in 37.9% of patients. At the data cutoff (median follow-up of 9.0 months), treatment had been discontinued in 21 patients, with such discontinuation being due to TRAEs in 12 (41.4%) patients. However, after exclusion of one patient with progressive disease, the remaining 11 patients showed long-term antitumor efficacy after treatment discontinuation (range of response duration, 0.9+ to 15.6+ months). The median PFS was 13.8 months (95% CI, 13.7 months to not reached [NR]) and the median OS was NR (95% CI, 13.7 months to NR), with a 12-month OS rate of 79.5%. CONCLUSION: NIVO plus LD-IPI showed robust and durable antitumor efficacy as a first-line treatment for MSI-H AGC. Although TRAEs often led to treatment discontinuation, treatment efficacy was subsequently sustained in most patients.

Nivolumab (NIVO) plus low-dose ipilimumab (IPI) has shown a promising survival benefit in first-line treatment of microsatellite instability-high (MSI-H) colorectal cancer. We hypothesized that this regimen might also be beneficial for MSI-H gastric cancer (GC), which accounts for ~5% of all GC cases. NO LIMIT (WJOG13320G/CA209-7W7) is an investigator-initiated, single-arm, open-label, 14-center phase 2 trial of NIVO plus low-dose IPI for MSI-H GC in the first-line setting. Eligibility criteria include unresectable advanced, recurrent, or metastatic gastric or esophagogastric junction cancer with a histologically confirmed diagnosis of adenocarcinoma; confirmed MSI-H status with the MSI-IVD Kit (FALCO); no prior systemic anticancer therapy; an Eastern Cooperative Oncology Group performance status of 0 or 1; and a measurable lesion per RECIST 1.1. The primary objective of the study is to determine the overall response rate (ORR) for the NIVO+IPI regimen as assessed by blinded independent central review. Secondary end points include progression-free survival, overall survival, duration of response, safety, tolerability, and biomarkers. The number of patients was set at 28 on the basis of the threshold and expected ORR values of 35 and 65%, respectively, with a one-sided alpha error of 0.025 and power of 0.80. Subjects will receive treatment with nivolumab (240 mg) biweekly in combination with ipilimumab (1 mg/kg) every 6 weeks. The results of this study should clarify the therapeutic potential of NIVO+IPI for MSI-H GC in the first-line setting. Trial registration: JapicCTI-205400.

Aberrant fibroblast growth factor receptor (FGFR)-driven signaling, predominantly arising from FGFR2 amplification, plays a key role in gastric cancer pathogenesis. This open-label, phase 2 study evaluated the efficacy and safety of futibatinib, an irreversible FGFR1-4 inhibitor, in patients with gastric or gastroesophageal junction (GEJ) cancer harboring FGFR2 amplifications. Patients were treated with futibatinib 20 mg orally once daily in a 28-day cycle. The primary endpoint was objective response rate (ORR) per independent central review. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Among 28 treated patients, the ORR per independent central review was 17.9 %, comprising five patients with a partial response (median duration of response, 3.9 months), and an additional nine patients with stable disease for a disease control rate of 50.0 %. Median PFS per independent central review and median OS were 2.9 and 5.9 months, respectively. The most common treatment-related adverse events (any grade) were hyperphosphatemia (89.3 %), decreased appetite (32.1 %), and increased aspartate aminotransferase (21.4 %). Only one (3.6 %) patient discontinued study treatment due to an adverse event. Futibatinib demonstrated modest antitumor activity with a safety profile consistent with previous reports in patients with gastric or GEJ cancer harboring FGFR2 amplifications, potentially warranting further investigation.