Transcriptomic Signatures of MSI-High Metastatic Colorectal Cancer Predict Efficacy of Immune Checkpoint Inhibitors

Predictors of response to immunotherapy in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related deaths globally. While treatment advancements have improved survival rates, primarily through targeted therapies based on KRAS, NRAS, and BRAF mutations, personalized treatment strategies for CRC remain limited. Immunotherapy, mainly immune checkpoint blockade, has shown efficacy in various cancers but is effective in only a small subset of patients with CRC with deficient mismatch repair (dMMR) proteins or high microsatellite instability (MSI). Recent research has challenged the notion that CRC is immunologically inert, revealing subsets with high immunogenicity and diverse lymphocytic infiltration. Identifying precise biomarkers beyond dMMR and MSI is crucial to expanding immunotherapy benefits. Hence, exploration has extended to various biomarker sources, such as the tumor microenvironment, genomic markers, and gut microbiota. Recent studies have introduced a novel classification system, consensus molecular subtypes, that aids in identifying patients with CRC with an immunogenic profile. These findings underscore the necessity of moving beyond single biomarkers and toward a comprehensive understanding of the immunological landscape in CRC, facilitating the development of more effective, personalized therapies.

Immune-inflammatory markers and clinical characteristics as predictors of the depth of response and prognosis of patients with PD-L1 ≥50% metastatic non-small cell lung cancer receiving first-line immunotherapy

BACKGROUND

Patients with programmed cell death-ligand 1 (PD-L1) ≥50% metastatic non-small cell lung cancer (NSCLC) treated with first-line immunotherapy showed heterogeneous tumor responses. In this study, we investigated the clinical and immune-inflammatory markers distinguishing patients with metastatic NSCLC achieving high depth of tumor response (HDPR) from those with non-high depth of response (NHDPR). The impact of clinical features on the prognosis of patients with PD-L1 ≥50% were further clarified.

METHODS

The clinical characteristics and immune-inflammatory markers of 17 patients with PD-L1 ≥50% metastatic NSCLC at Beijing Tiantan Hospital between July 2020 and December 2023 were retrospectively analyzed.

RESULTS

Among the 17 patients, seven (41.2%) patients achieved HDPR (range: -50%, -72%) and 10 (58.8%) patients achieved NHDPR (range: -13%, -45%). Below normal CD4 + T lymphocytes/CD8 + T lymphocytes (CD4/CD8) ratio (p = 0.01) and oncogenes and/or tumor suppressor gene mutations (TP53/KRAS/EGFR) (p = 0.001) were found enriched for NHDPR compared with HDPR. With a median follow-up of 26.0 months (range: 17.2-34.8 months), the median progression-free survival (PFS) following first-line immunotherapy and overall survival (OS) were 9.0 months (95% CI: 5.0-13.0) and not reached (NR), respectively. The neutrophil-to-lymphocyte ratio (NLR) was identified as an independent prognostic factor on first-line PFS. Patients with an NLR ≥4 exhibited a shorter median PFS (7.0 months vs. NR; p = 0.033; 95% CI: 1.2-80.2) than those with an NLR <4 following first-line immunotherapy.

CONCLUSIONS

Among patients with PD-L1 ≥50% metastatic NSCLC who received first-line immunotherapy, a lower CD4/CD8 ratio and the presence of genes mutations showed a diminished tumor response and a higher NLR ratio exhibited a worse median PFS.

PD-1 blockade plus COX inhibitors in dMMR metastatic colorectal cancer: Clinical, genomic, and immunologic analyses from the PCOX trial

BACKGROUND

Approximately 20% of patients with DNA mismatch repair deficiency (dMMR) metastatic colorectal cancer do not respond to anti-programmed death-1 (PD-1) ligand therapy, and baseline biomarkers of response are lacking.

METHODS

We conducted a phase 2 study to evaluate the efficacy of cyclooxygenase (COX) inhibitors in combination with anti-PD-1 therapy in patients with dMMR metastatic colorectal cancer. The primary endpoint was objective response rate. The secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate, duration of response, and safety.

FINDINGS

A total of 30 patients were enrolled, and the objective response rate was 73.3%, meeting the predefined endpoint of 68%. The median PFS and median OS were not reached at a median follow-up period of 50.8 months. Disease control was achieved in 28 patients (93.3%). The median duration of response was not reached. The combination was well tolerated. Multiomics analysis revealed that the antigen processing and presentation pathway was positively associated with treatment response and PFS. Higher TAPBP expression was predictive of better PFS (log-rank p = 0.003), and this prognostic significance was confirmed in an immunotherapy validation cohort.

CONCLUSIONS

Thus, COX inhibitors combined with PD-1 blockade may be effective and safe treatment options for patients with dMMR metastatic colorectal cancer, and TAPBP may serve as a biomarker for immune checkpoint inhibitor therapy (this study was registered at ClinicalTrials.gov: NCT03638297).

FUNDING

Funded by the National Natural Science Foundation of China (81974369) and the program of Guangdong Provincial Clinical Research Center for Digestive Diseases (2020B1111170004).

Resistance to immune checkpoint inhibitors in colorectal cancer with deficient mismatch repair/microsatellite instability: misdiagnosis, pseudoprogression and/or tumor heterogeneity?

Colorectal carcinoma (CRC) with deficiency of the deficient mismatch repair (dMMR) pathway/microsatellite instability (MSI) is characterized by a high mutation load and infiltration of immune cells in the tumor microenvironment. In agreement with these findings, clinical trials have demonstrated a significant activity of immune checkpoint inhibitors (ICIs) in dMMR/MSI metastatic CRC (mCRC) patients and, more recently, in CRC patients with early disease undergoing neoadjuvant therapy. However, despite high response rates and durable clinical benefits, a fraction of mCRC patients, up to 30%, showed progressive disease when treated with single agent anti-programmed cell death 1 (PD-1) antibody. This article discusses the three main causes that have been associated with early progression of dMMR/MSI mCRC patients while on treatment with ICIs, i.e., misdiagnosis, pseudoprogression and tumor heterogeneity. While pseudoprogression probably does not play a relevant role, data from clinical studies demonstrate that some dMMR/MSI CRC cases with rapid progression on ICIs may be misdiagnosed, underlining the importance of correct diagnostics. More importantly, evidence suggests that dMMR/MSI mCRC is a heterogeneous group of tumors with different sensitivity to ICIs. Therefore, we propose novel diagnostic and therapeutic strategies to improve the outcome of dMMR/MSI CRC patients.