A randomised, open-label, phase 3 trial published in The BMJ has reported that initial treatment with camrelizumab combined with capecitabine and oxaliplatin (CAPOX), followed by camrelizumab-based maintenance therapy, produced statistically significant improvements in overall survival compared with CAPOX chemotherapy alone in patients with previously untreated, human epidermal growth factor receptor 2 (HER2) negative, unresectable locally advanced or metastatic gastric or gastro-oesophageal junction (GOJ) adenocarcinoma. The findings carry particular relevance for oncology practices managing a cancer subtype that continues to represent a substantial global burden, including in Pacific Rim populations where gastric malignancy incidence remains disproportionately elevated.

Study Design and Patient Population

The trial enrolled 885 adults aged 18 years or older across 75 hospital sites in China between March 2019 and August 2021. All participants carried histologically confirmed HER2-negative, unresectable locally advanced or metastatic gastric or GOJ adenocarcinoma and had received no prior systemic therapy for advanced disease. Randomisation proceeded in a 2:2:1 ratio across three treatment arms. The third arm, camrelizumab plus CAPOX followed by camrelizumab monotherapy maintenance (camre+CAPOX followed by camre), was introduced midway through the enrolment period, a design feature the investigators acknowledged as a limitation affecting the statistical interpretation of comparisons involving that arm.

Stratification variables included Eastern Cooperative Oncology Group (ECOG) performance status, the presence of peritoneal metastasis, and programmed death ligand 1 (PD-L1) combined positive score (CPS). The PD-L1 CPS threshold of greater than 1 defined the prespecified PD-L1 positive subpopulation, which served as one of the two primary analysis populations alongside the overall intention-to-treat population.

Of the 885 enrolled participants, 352 received camrelizumab plus CAPOX followed by camrelizumab plus apatinib maintenance (camre+CAPOX followed by camre+apa), 349 received CAPOX alone, and 177 received camre+CAPOX followed by camre. The primary endpoint was overall survival, assessed first in the PD-L1 positive population and then in the overall population for the primary comparison of camre+CAPOX followed by camre+apa versus CAPOX alone. The comparisons involving the third arm were designated as descriptive rather than confirmatory, limiting the strength of inferential conclusions that can be drawn from those results.

Overall Survival Outcomes

At the time of data cutoff, 454 of 592 patients (76.7%) in the PD-L1 positive population and 709 of 878 patients (80.8%) in the overall population had died, providing a mature dataset for survival analysis.

In the primary comparison, camre+CAPOX followed by camre+apa demonstrated a statistically significant overall survival advantage over CAPOX alone in the PD-L1 positive population. Median overall survival reached 15.0 months in the combination arm versus 12.5 months in the chemotherapy-alone arm, corresponding to a hazard ratio (HR) of 0.80 (95% confidence interval [CI] 0.65 to 0.98; one-sided P=0.02). In the overall population, median overall survival was 13.5 months versus 12.1 months, with an HR of 0.80 (95% CI 0.68 to 0.94; one-sided P=0.004).

The descriptive analysis of camre+CAPOX followed by camre versus CAPOX alone produced numerically comparable and nominally statistically significant findings. In the PD-L1 positive population, median overall survival was 15.3 months versus 12.5 months (HR 0.76, 95% CI 0.58 to 0.97; one-sided nominal P=0.01). In the overall population, median overall survival was 14.2 months versus 12.1 months (HR 0.80, 95% CI 0.65 to 0.98; one-sided nominal P=0.02). The investigators reported no overall survival benefit when comparing camre+CAPOX followed by camre+apa against camre+CAPOX followed by camre, suggesting that the addition of apatinib, an oral vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitor, to the maintenance phase did not confer incremental benefit beyond camrelizumab alone in the maintenance setting.

Mechanistic Context

Camrelizumab is a humanised immunoglobulin G4 (IgG4) monoclonal antibody targeting the programmed death 1 (PD-1) receptor. By blocking the interaction between PD-1 and its ligands PD-L1 and PD-L2, camrelizumab attenuates tumour-mediated suppression of cytotoxic T lymphocyte activity within the tumour microenvironment. The biological rationale for combining PD-1 checkpoint inhibition with oxaliplatin-based chemotherapy rests, in part, on preclinical observations that platinum compounds induce immunogenic cell death, releasing damage-associated molecular patterns capable of priming antitumour immune responses. Whether this immunogenic priming effect translates reliably into enhanced checkpoint inhibitor efficacy in the human gastric cancer microenvironment has been an active area of investigation, and the present trial adds clinical weight to that mechanistic hypothesis, at least in the HER2-negative population.

Apatinib’s mechanism of action as a VEGFR-2 inhibitor targets tumour angiogenesis. The absence of an additive survival benefit when apatinib was incorporated into the maintenance regimen is a finding of consequence. Anti-angiogenic agents have shown variable benefit in gastric cancer, and the present results suggest that, in the maintenance context following camrelizumab plus CAPOX induction, apatinib did not augment the immunological or survival benefit attributable to continued PD-1 inhibition. This observation merits further investigation to determine whether specific molecular subgroups, including those defined by tumour vascularity markers or angiogenic gene expression profiles, might derive differential benefit from VEGFR-targeted maintenance.

Safety Profile

Treatment-related adverse events (TRAEs) of grade 3 or higher occurred in 239 of 352 patients (67.9%) in the camre+CAPOX followed by camre+apa group, compared with 158 of 349 patients (45.3%) in the CAPOX alone group and 83 of 177 patients (46.9%) in the camre+CAPOX followed by camre group. The substantially higher rate of severe TRAEs in the apatinib-containing arm relative to both comparators represents a clinically material finding. The known toxicity profile of apatinib, including hypertension, hand-foot syndrome, and proteinuria, likely contributed to this difference and reinforces the interpretation that the addition of apatinib in the maintenance phase increases toxicity burden without a corresponding survival gain.

The CAPOX-alone arm and the camre+CAPOX followed by camre arm demonstrated comparable rates of grade 3 or higher TRAEs at 45.3% and 46.9%, respectively. This similarity suggests that the addition of camrelizumab to chemotherapy and subsequent maintenance with the checkpoint inhibitor alone does not substantially amplify severe toxicity beyond that expected with standard CAPOX, an observation that may support the tolerability of the camrelizumab-containing regimen in clinical practice.

Clinicians considering these data should account for the spectrum of immune-related adverse events (irAEs) associated with PD-1 blockade, including pneumonitis, hepatitis, endocrinopathies, and reactive capillary hemangiomatosis, a cutaneous phenomenon reported with particular frequency with camrelizumab relative to other PD-1 inhibitors. The incidence and severity of irAEs in the present trial were not detailed in the available summary, and full safety tables from the published manuscript warrant careful review before extrapolating to patient populations in clinical settings outside the trial context.

Translational Considerations and Clinical Applicability

Several translational considerations temper direct application of these results. The trial was conducted exclusively in China, and the enrolled population was drawn from a clinical and genomic context that may differ from patients presenting in Hawaii and broader United States practice settings. Gastric cancer genomics demonstrate notable geographic and ethnic heterogeneity, with differing rates of Epstein-Barr virus associated tumours, microsatellite instability high (MSI-H) tumours, and chromosomally unstable subtypes