Mode
Text Size
Log in / Sign up

Phase 2 trial links early monocyte elevation to response in gastric cancer immunotherapySmall study finds immune cell changes linked to better response in gastric cancer treatment

AI-generated summary of the cited source, checked by automated accuracy review. How we work

Key Takeaway
Consider early monocyte changes as a potential, unvalidated biomarker in gastric cancer immunotherapy.

A phase 2 clinical trial investigated circulating immune cells and mechanisms underlying the therapeutic effects of pembrolizumab plus capecitabine/oxaliplatin (XELOX) in 24 patients with metastatic gastric cancer undergoing first-line therapy. The study design involved collecting blood samples at baseline, after one cycle of XELOX alone (FU1), and 18 weeks after adding pembrolizumab (FU2). No comparator group was reported, and the primary outcome was not specified.

The main findings were correlational. At FU1, the proportion of PBMC monocytes was significantly higher in responders compared to non-responders. Gene expression of CXCL8, CCL3, and CCL4 was significantly upregulated in responders at the same timepoint. After adding pembrolizumab, memory CD8 T cells (CD3+CD8+CD27+CD28+CD45RO+) increased in responders compared to non-responders. Most notably, early elevation of circulating monocytes correlated with better survival. No effect sizes, absolute numbers, p-values, or confidence intervals were reported for these findings.

Safety and tolerability data were not reported. Key limitations include the small sample size of 24 patients, the observational and correlational nature of the findings which preclude causal inference, and the absence of reported statistical measures for key outcomes. The study suggests early distinct changes in blood myeloid cells during chemotherapy might be used to assess clinical response, but this hypothesis-generating research from a phase 2 trial requires rigorous confirmation.

Researchers studied 24 patients with metastatic gastric cancer who were receiving a combination treatment of pembrolizumab (an immunotherapy drug) plus chemotherapy (XELOX). They wanted to understand how the immune system responds to this treatment and whether certain immune cell changes could predict who might benefit most.

The study found that patients who responded well to treatment showed early increases in certain immune cells called monocytes in their blood. These patients also had higher levels of specific memory T cells and certain immune signaling molecules. The researchers observed that these early immune changes were linked to better survival outcomes.

This was a very small, early-phase study that only included 24 patients. The researchers reported correlations between immune changes and treatment response, but they did not provide statistical measures like p-values or confidence intervals to show the strength of these relationships. The study design cannot prove that these immune changes cause better outcomes—it only shows they are associated.

Readers should understand this is preliminary research that helps scientists understand potential immune mechanisms. The findings need to be confirmed in much larger studies before they could potentially be used to guide treatment decisions for patients.

What this means for you:
Early immune cell changes were linked to better treatment response in a small gastric cancer study, but larger trials are needed.

Study Details

Study typePhase2
Sample sizen = 24
EvidenceLevel 3
PublishedMar 2026
View Original Abstract ↓
Combination therapy with immune checkpoint inhibitors (ICIs) and chemotherapy has reshaped metastatic gastric cancer (GC) treatment, improving response rate, progression-free survival, and overall survival. We aimed to explore circulating immune cells and elucidate the mechanisms underlying the therapeutic effects of pembrolizumab and capecitabine/oxaliplatin (XELOX) in patients with metastatic GC. Potential immune mechanisms in GC tumors were retrospectively examined among patients from our phase 2 chemoimmunotherapy trial. Peripheral blood samples from patients with GC undergoing first-line pembrolizumab plus XELOX therapy were monitored using high-dimensional cytometry. Matched paired-tissue single-cell RNA-seq data were analyzed. Samples were collected from 24 patients at baseline, after one cycle of XELOX (FU1), and 18 weeks after pembrolizumab addition (FU2). Natural killer cell (CD3-NCAM +) and myeloid cell (CD11c + or CD14 +) subsets increased during chemoimmunotherapy.-At FU1, the proportion of PBMC monocytes was significantly higher in responders compared to non-responders. Consistent with the increase in monocyte-derived macrophages (M1-like) in paired tissues, monocytes in peripheral blood mononuclear cells increased at FU1. Immunosenescence score revealed recently mobilized monocytes infiltrating the tumor bed after chemotherapy. Gene expression analysis showed significantly upregulated CXCL8, CCL3, and CCL4 in FU1 responders. Early elevation of circulating monocytes correlated with better survival. After adding pembrolizumab, memory CD8 (CD3 + CD8 + CD27 + CD28 + CD45RO +) T cells increased in responders compared to non-responders. Our results elucidate the serial immunological landscape underpinning favorable responses to first-line ICI plus chemotherapy in patients with gastric cancer. Early distinct changes in blood myeloid cells during chemotherapy can be used to assess clinical response.
Free Newsletter

Clinical research that matters. Delivered to your inbox.

Join thousands of clinicians and researchers. No spam, unsubscribe anytime.