Pembrolizumab versus chemotherapy for microsatellite instability-high or mismatch repair-deficient metastatic colorectal cancer (KEYNOTE-177): final analysis of a randomised, open-label, phase 3 study

Relevance of mutation-derived neoantigens and non-classical antigens for anticancer therapies

Efficacy of cancer immunotherapies relies on correct recognition of tumor antigens by lymphocytes, eliciting thus functional responses capable of eliminating tumor cells. Therefore, important efforts have been carried out in antigen identification, with the aim of understanding mechanisms of response to immunotherapy and to design safer and more efficient strategies. In addition to classical tumor-associated antigens identified during the last decades, implementation of next-generation sequencing methodologies is enabling the identification of neoantigens (neoAgs) arising from mutations, leading to the development of new neoAg-directed therapies. Moreover, there are numerous non-classical tumor antigens originated from other sources and identified by new methodologies. Here, we review the relevance of neoAgs in different immunotherapies and the results obtained by applying neoAg-based strategies. In addition, the different types of non-classical tumor antigens and the best approaches for their identification are described. This will help to increase the spectrum of targetable molecules useful in cancer immunotherapies.

Prophylaxis with abemaciclib delays tumorigenesis in dMMR mice by altering immune responses and reducing immunosuppressive extracellular vesicle secretion

BACKGROUND

The CDK4/6 inhibitor abemaciclib is an FDA-approved agent and induces T-cell-mediated immunity. Previously, we confirmed the therapeutic potential of abemaciclib on mismatch repair-deficient (dMMR) tumors in mice. Here, we applied a prophylactic administration/dosage setting using two preclinical mouse models of dMMR-driven cancer.

METHODS

Mlh1-/- and Msh2loxP/loxP mice received repeated prophylactic applications of abemaciclib mesylate (75 mg/kg bw, per oral) as monotherapy or were left untreated. Blood phenotyping and multiplex cytokine measurements were performed regularly. The tumor microenvironment was evaluated by immunofluorescence and Nanostring-based gene expression profiling. Numbers, size and immune composition and activity of extracellular vesicles (EVs) were studied at the endpoint.

FINDINGS

Prophylactic abemaciclib-administration delayed tumor development and significantly prolonged overall survival in both mouse strains (Mlh1-/-: 50.0 wks vs. control: 33.9 wks; Msh2loxP/loxP;TgTg(Vil1-cre: 58.4 wks vs. control 44.4 wks). In Mlh1-/- mice, pro-inflammatory cytokines (IL-2, IL-6) significantly increased, whereas IL-10 and IL-17A decreased. Circulating and splenic exhausted and regulatory T cell numbers were significantly lower in the abemaciclib groups. Deeper analysis of late-onset tumors revealed activation of the Hedgehog and Notch signaling in Mlh1-/- mice, and activation of the MAPK pathway in Msh2loxP/loxP;TgTg(Vil1-cre mice. Still, arising tumors had fewer infiltrating myeloid-derived suppressor cells (vs. control). Notably, prophylactic abemaciclib-administration prevented secretion of procoagulant EVs but triggered release of immunomodulatory EVs in Mlh1-/- mice.

INTERPRETATION

Prophylactic abemaciclib prolongs survival via global immunomodulation. Prophylactic use of abemaciclib should be considered further for individuals with inherited dMMR.

FUNDING

This work was supported by grants from the German research foundation [DFG grant number: MA5799/2-2] and the Brigitte und Dr. Konstanze Wegener-Stiftung to CM.

Lenvatinib Plus Pembrolizumab Versus Standard of Care for Previously Treated Metastatic Colorectal Cancer: Final Analysis of the Randomized, Open-Label, Phase III LEAP-017 Study

PURPOSE

Treatment options are limited for patients with previously treated metastatic colorectal cancer (mCRC). In the LEAP-017 study, we evaluate whether lenvatinib in combination with pembrolizumab improves outcomes compared with standard of care (SOC) in previously treated mismatch repair proficient or not microsatellite instability high (pMMR or not MSI-H) mCRC.

METHODS

In this international, multicenter, randomized, controlled, open-label, phase III study, eligible patients age 18 years and older with unresectable, pMMR or not MSI-H mCRC, that had progressed on or after, or could not tolerate, standard treatment, were randomly assigned 1:1 to lenvatinib 20 mg orally once daily plus pembrolizumab 400 mg intravenously once every 6 weeks or investigator's choice of regorafenib or trifluridine/tipiracil (SOC). Randomization was stratified by presence or absence of liver metastases. The primary end point was overall survival (OS). LEAP-017 is registered at ClinicalTrials.gov (NCT04776148), and has completed recruitment.

RESULTS

Between April 8, 2021, and December 21, 2021, 480 patients were randomly assigned to lenvatinib plus pembrolizumab (n = 241) or SOC (n = 239). At final analysis (median follow-up of 18.6 months [IQR, 3.9]), median OS with lenvatinib plus pembrolizumab versus SOC was 9.8 versus 9.3 months (hazard ratio [HR], 0.83 [95% CI, 0.68 to 1.02]; P = .0379; prespecified threshold P = .0214). Grade ≥3 treatment-related adverse events occurred in 58.4% (lenvatinib plus pembrolizumab) versus 42.1% (SOC) of patients. Two participants died due to treatment-related adverse events, both in the lenvatinib plus pembrolizumab arm.

CONCLUSION

In patients with pMMR or not MSI-H mCRC that had progressed on previous therapy, there was no statistically significant improvement in OS after lenvatinib plus pembrolizumab treatment versus SOC. No new safety signals were observed.

Two-Year Outcomes and Biomarker Analysis of Locally Advanced Gastric and Gastroesophageal Junction Adenocarcinoma After Neoadjuvant Chemotherapy and Immunotherapy from the Phase II WuhanUHGI001 Trial

BACKGROUND

This study reports the 2-year outcomes and biomarker analysis results of patients with locally advanced gastric and gastroesophageal junction (G/GEJ) adenocarcinoma who received neoadjuvant chemotherapy and immunotherapy in a phase II WuhanUHGI001 trial.

METHODS

Eligible patients with cT3/4aN+M0 locally advanced G/GEJ adenocarcinoma were screened, enrolled, and treated with 3 cycles of neoadjuvant tislelizumab and SOX followed by D2 gastrectomy and another 5 cycles of postoperative adjuvant SOX. The primary endpoint was major pathological response.

RESULTS

Of the 49 included patients, 24 (49.0%) achieved major pathological response and 13 (26.5%) achieved pathological complete response. During a median follow-up of 26.8 months, the 2-year progression-free survival (PFS) and overall survival (OS) rates were 69.4% and 81.2%, respectively. Grade 3-4 adverse events occurred in six patients (12.2%) during the neoadjuvant period, eight patients (17.0%) during the postoperative period, and seven patients (15.2%) during the adjuvant period. Biomarker analysis revealed that the pathological complete response showed no association with 2-year PFS and OS. Major pathological response showed a potentially strong association with improved 2-year PFS and OS rates. In addition, preoperative circulating tumor cells combined with pathological responses are helpful in prognosis assessment. In addition, our results showed that T downstaging, lymphocyte-to-monocyte ratio, and CD3+ T cells were independent factors that affect PFS. The signet ring cell component (SRCC), T downstaging, and neutrophil-to-lymphocyte ratio were independent factors affecting OS. Prognostic nomograms of PFS and OS constructed based on the multivariate Cox regression results demonstrated suitable calibration and discrimination ability.

CONCLUSIONS

Neoadjuvant tislelizumab plus SOX exhibits promising efficacy and acceptable toxicity in patients with locally advanced G/GEJ adenocarcinoma. In addition, our study established a prognostic risk signature and nomograms based on clinicopathological characteristics, which can accurately predict patient outcomes and aid in personalized treatment planning.

YTHDF1 regulates GID8-mediated glutamine metabolism to promote colorectal cancer progression in a m6A-dependent manner

Dysregulation of epigenetics is a hallmark of cancer development, and YTHDF1 stands out as a crucial epigenetic regulator with the highest DNA copy number variation among all N6-methyladenosine (m6A) regulators in colorectal cancer (CRC) patients. Here, we aimed to investigate the specific contribution of YTHDF1 overexpression to CRC progression and its consequences. Through multiple bioinformatic analysis of human cancer databases and clinical CRC samples, we identified GID8/Twa1 as a crucial downstream target of YTHDF1. YTHDF1 manipulates GID8 translation efficiency in a m6A-dependent manner, and high expression of GID8 is associated with more aggressive tumor progression and poor overall survival. Mechanistically, GID8 is intimately associated with glutamine metabolic demands by maintaining active glutamine uptake and metabolism through the regulation of excitatory amino acid transporter 1 (SLC1A3) and glutaminase (GLS), thereby facilitating the malignant progression of CRC. Inhibition of GID8 attenuated CRC proliferation and metastasis both in vitro and in vivo. In summary, we identified a previously unknown target pertaining to glutamine uptake and metabolism in tumor cells, underscoring the potential of GID8 in the treatment of CRC.

Recent developments in immunotherapy for gastrointestinal tract cancers

The past few decades have witnessed the rise of immunotherapy for Gastrointestinal (GI) tract cancers. The role of immune checkpoint inhibitors (ICIs), particularly programmed death protein 1 (PD-1) and PD ligand-1 antibodies, has become increasingly pivotal in the treatment of advanced and perioperative GI tract cancers. Currently, anti-PD-1 plus chemotherapy is considered as first-line regimen for unselected advanced gastric/gastroesophageal junction adenocarcinoma (G/GEJC), mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC), and advanced esophageal cancer (EC). In addition, the encouraging performance of claudin18.2-redirected chimeric antigen receptor T-cell (CAR-T) therapy in later-line GI tract cancers brings new hope for cell therapy in solid tumour treatment. Nevertheless, immunotherapy for GI tumour remains yet precise, and researchers are dedicated to further maximising and optimising the efficacy. This review summarises the important research, latest progress, and future directions of immunotherapy for GI tract cancers including EC, G/GEJC, and CRC.

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).

A Novel Gene Signature Associated with Protein Post-translational Modification to Predict Clinical Outcomes and Therapeutic Responses of Colorectal Cancer

Accumulated evidence highlights the biological significance of diverse protein post-translational modifications (PTMs) in tumorigenicity and progression of colorectal cancer (CRC). In this study, ten PTM patterns (ubiquitination, methylation, phosphorylation, glycosylation, acetylation, SUMOylation, citrullination, neddylation, palmitoylation, and ADP-ribosylation) were analyzed for model construction. A post-translational modification index (PTMI) with a 14-gene signature was established. CRC patients with high PTMI had a worse prognosis after validating in nine independent datasets. By incorporating PTMI with clinical features, a nomogram with excellent predictive performance was constructed. Two molecular subtypes of CRC with obvious difference in survival time were identified by unsupervised clustering. Furthermore, PTMI was related to known immunoregulators and key tumor microenvironment components. Low-PTMI patients responded better to fluorouracil-based chemotherapy and immune checkpoint blockade therapy compared to high-PTMI patients, which was validated in multiple independent datasets. However, patients with high PTMI might be sensitive to bevacizumab. In short, we established a novel PTMI model by comprehensively analyzing diverse post-translational modification patterns, which can accurately predict clinical prognosis and treatment response of CRC patients.

A registry-based study on universal screening for defective mismatch repair in colorectal cancer in Denmark highlights disparities in screening uptake and counselling referrals

Universal screening for defective mismatch repair (dMMR) in colorectal cancer utilizes immunohistochemical staining for MLH1, MSH2, MSH6 and PSM2. Additionally, BRAF V600E mutations status and MLH1 hypermethylation should be performed to distinguish germline and somatic dMMR alterations. A decade of Danish population-based registries has been analysed regarding screening uptake, detection rate and referral to genetic counselling. MMR testing was performed in 71·8% (N = 34,664) of newly diagnosed colorectal cancers with an increasing trend to 88·8% coverage in the study's final year. The likelihood of undergoing MMR testing was reduced in males with 2% (95% CI 0·4-2·7, p = 0·008), with 4·1% in patients above age 70 years (95% CI 1·5-6·6, p = 0·003) compared in patients below age 51 years, with 16·3% in rectal cancers (95% CI 15·1-17·6, p < 0·001) and 1·4% left-sided colon cancers (95% CI 0·1-1·7, p = 0·03) compared to right-sided colon cancers. Tumour stage II and III increased the likelihood of being tested, with 3·7% for stage II (95% CI 2·2-5·6, p < 0·001) and 3·3% for stage III tumours (95% CI 1·8-4·8, p < 0·001) compared to stage I tumours, whereas the likelihood for stage IV tumours is reduced by 35·7% (95% CI 34·2-37·2, p < 0·001). Test rates significantly differed between the Danish health care regions. dMMR was identified in 15·1% (95% CI 14·8-15·6, p < 0·001) cases with somatic MMR inactivation in 6·7% of the cases. 8·3% tumours showed hereditary dMMR expression patterns, and 20·0% of those were referred to genetic counselling. Despite the high uptake rates, we found disparities between patient groups and missed opportunities for genetic diagnostics.

Performance of Low-Dose Immunotherapy and Standard-Dose Immunotherapy in Microsatellite Instability-High Metastatic Colorectal Cancer: Real-World Data (CLouD-High Study)

PURPOSE

Standard-dose immune checkpoint inhibitors (SD-ICIs) are the standard of care as initial therapy in microsatellite instable-high (MSI-H) advanced/metastatic colorectal adenocarcinomas (mCRC), but there are preclinical data to suggest that low-dose ICIs (LD-ICI) might also have similar efficacy.

MATERIALS AND METHODS

A retrospective study of patients with MSI-H mCRC receiving ICIs between June 2017 and January 2023 was conducted. The primary end point of the study was 12-month progression-free survival (PFS), which was computed using the Kaplan-Meier method.

RESULTS

A total of 65 patients were available for analysis during the study period. Sixty patients (92%) received nivolumab, whereas the remaining received pembrolizumab. First-line ICIs were received by 18 patients (28%), whereas 47 patients (72%) received ICIs during later lines. Thirty patients (47%) received LD-ICIs (all received nivolumab), with the remaining receiving SD-ICIs (53%). At a median follow-up of 16.5 (95% CI, 11.8 to 21.2) months, median PFS was not reached in the entire cohort. The 12-month PFS rate in the LD-ICI cohort was 90%, whereas it was 75.8% in the SD-ICI cohort. There were no statistical differences in patients receiving ICIs as first-line therapy (12 months PFS-94.4%) or during later lines of therapy (12-month PFS-77.9%; P = .56).

CONCLUSION

ICIs in the current study show survivals which are similar to those seen in seminal trials in patients with MSI-H mCRC. Low-dose ICIs appear to work in MSI-H mCRC and should be explored prospectively in clinical trials. Patients with MSI-H status should be exposed to ICIs, whether initially or later during treatment, whenever feasible.

Improving the efficiency of immune checkpoint inhibitors for metastatic pMMR/MSS colorectal cancer: Options and strategies

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment and been extensively used for patients with metastastic colorectal cancer (mCRC), especially those harboring deficient mismatch repair/ microsatellite instability (dMMR/MSI). However, the majority of mCRC are classified as proficient mismatch repair/microsatellite stability(pMMR/MSS) type characterized by a cold immune microenvironment, rendering them generally unresponsive to ICIs. How to improve the efficacy of ICIs for these patients is an important issue to be solved. On the one hand, it is urgent to discover the predictive biomarkers and clinical characteristics associated with effectiveness and expand the subset of pMMR/MSS mCRC patients who benefit from ICIs. Additionally, combined strategies are being explored to modulate the immune microenvironment of pMMR/MSS CRC and facilitate the conversion of cold tumors into hot tumors. In this review, we have focused on the recent advancements in the predictive biomarkers and combination therapeutic strategies with ICIs for pMMR/MSS mCRC.

The long-term effectiveness and mechanism of oncolytic virotherapy combined with anti-PD-L1 antibody in colorectal cancer patient

Colorectal cancer (CRC) is known to be resistant to immunotherapy. In our phase-I clinical trial, one patient achieved a 313-day prolonged response during the combined treatment of oncolytic virotherapy and immunotherapy. To gain a deeper understanding of the potential molecular mechanisms, we performed a comprehensive multi-omics analysis on this patient and three non-responders. Our investigation unveiled that, initially, the tumor microenvironment (TME) of this responder presented minimal infiltration of T cells and natural killer cells, along with a relatively higher presence of macrophages compared to non-responders. Remarkably, during treatment, there was a progressive increase in CD4+ T cells, CD8+ T cells, and B cells in the responder's tumor tissue. This was accompanied by a significant upregulation of transcription factors associated with T-cell activation and cytotoxicity, including GATA3, EOMES, and RUNX3. Furthermore, dynamic monitoring of peripheral blood samples from the responder revealed a rapid decrease in circulating tumor DNA (ctDNA), suggesting its potential as an early blood biomarker of treatment efficacy. Collectively, our findings demonstrate the effectiveness of combined oncolytic virotherapy and immunotherapy in certain CRC patients and provide molecular evidence that virotherapy can potentially transform a "cold" TME into a "hot" one, thereby improving sensitivity to immunotherapy.

Dostarlimab: A promising new PD-1 inhibitor for cancer immunotherapy

OBJECTIVE

Dostarlimab, a humanized monoclonal PD-1 blocking antibody, is being tested as a cancer therapy in this review. Specifically, it addresses mismatch repair failure in endometrial cancer and locally progressed rectal cancer patients.

DATA SOURCES

A thorough database search found Dostarlimab clinical trials and studies. Published publications and ongoing clinical trials on Dostarlimab's efficacy as a single therapy and in conjunction with other medicines across cancer types were searched.

DATA SUMMARY

The review recommends Dostarlimab for endometrial cancer mismatch repair failure, as supported by GARNET studies. The analysis also highlights locally advanced rectal cancer findings. In the evolving area of cancer therapy, immune checkpoint inhibitors including pembrolizumab, avelumab, atezolizumab, nivolumab, and durvalumab were discussed.

CONCLUSIONS

Locally advanced rectal cancer patients responded 100% to Dostarlimab. Many clinical trials, including ROSCAN, AMBER, IOLite, CITRINO, JASPER, OPAL, PRIME, PERLA, and others, are investigating Dostarlimab in combination treatment. This research sheds light on Dostarlimab's current and future possibilities, in improving cancer immunotherapy understanding.

STELLAR-303: randomized phase III study of zanzalintinib + atezolizumab in previously treated metastatic colorectal cancer

Most patients with metastatic colorectal cancer (mCRC) have limited treatment options following standard-of-care therapy. VEGFR-tyrosine kinase inhibitors (TKIs) have demonstrated clinical activity in mCRC in combination with immune checkpoint inhibitors (ICIs), particularly in patients without liver metastases. The TKI zanzalintinib (XL092) targets VEGFR, MET and TAM kinases, proteins that are involved in tumor growth, angiogenesis, metastasis and immunosuppression. Zanzalintinib has immunomodulatory properties that may enhance response to ICIs. Presented is the design of STELLAR-303, a global, phase III, open-label, randomized study evaluating zanzalintinib plus atezolizumab versus regorafenib in patients with non-MSI-H mCRC who progressed during/after or are refractory/intolerant to standard-of-care therapy. The primary end point is overall survival in patients without liver metastases.Clinical Trial Registration: NCT05425940 (ClinicalTrials.gov).

Third-line treatment and beyond in metastatic colorectal cancer: What do we have and what can we expect?

Colorectal cancer remains the third most common cancer worldwide and the second cause of cancer-related death. Treatment advances and precision oncological medicine for these tumours have been stalled in comparison to those for other common tumours such as lung and breast cancer. However, the recent publication of the SUNLIGHT trial results with the trifluridine/tipiracil (TAS-102)-bevacizumab combination and the irruption of new molecular targets with guided treatments have opened new possibilities in third-line metastatic colorectal cancer management. Anti-EGFR rechallenge, anti-HER2 targeted therapies or the promising results of Pressurised Intraperitoneal Aerosol Chemotherapy (PIPAC), are some of the available options that may modify what is presumably third-line colorectal treatment. Hereby, we present the evidence of the different treatment options in third-line colorectal cancer and beyond, as well as the possibilities of sequencing them.

Colorectal cancer

Despite decreased incidence rates in average-age onset patients in high-income economies, colorectal cancer is the third most diagnosed cancer in the world, with increasing rates in emerging economies. Furthermore, early onset colorectal cancer (age ≤50 years) is of increasing concern globally. Over the past decade, research advances have increased biological knowledge, treatment options, and overall survival rates. The increase in life expectancy is attributed to an increase in effective systemic therapy, improved treatment selection, and expanded locoregional surgical options. Ongoing developments are focused on the role of sphincter preservation, precision oncology for molecular alterations, use of circulating tumour DNA, analysis of the gut microbiome, as well as the role of locoregional strategies for colorectal cancer liver metastases. This overview is to provide a general multidisciplinary perspective of clinical advances in colorectal cancer.

Efficacy and safety of PD-1/L1 inhibitors as first-line therapy for metastatic colorectal cancer: a meta-analysis

Objective

To evaluate the efficacy and safety of PD-1/L1 inhibitors as first-line therapy in metastatic colorectal cancer(mCRC).

Method

Articles evaluating first-line PD-1/L1 inhibitors for mCRC were sought in four databases (Pubmed, Embase, Web of Science, and the Cochrane Library) from the inception of the databases until 11 November 2023. Meta-analyses were conducted to assess the rates of progression-free survival (PFS), overall survival (OS), complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD), objective response rate (ORR), disease control rate (DCR), and grade ≥ 3 treatment-related adverse events (trAEs).

Results

Totally nine studies were included for meta-analysis. A subgroup analysis was performed based on mismatch repair(MMR) status and regimens. In patients diagnosed with mismatch repair-deficient(dMMR) mCRC who received PD-1/L1 inhibitors as their first-line treatment, the ORR was 0.54 (95% CI, 0.39 to 0.68), the median PFS was 53.2 months, the Grade≥ 3 TRAEs rate was 0.33(95% CI, 0.12 to 0.60) and the median OS was not determined. For patients with proficient mismatch repair (pMMR) mCRC who underwent a combined treatment of PD-1/L1 inhibitors, anti-VEGF monoclonal antibody and chemotherapy as their first-line therapy, the ORR was 0.62 (95% CI, 0.56 to 0.68), the median PFS was 10.1 months, the median OS was 26.7 months, and the Grade≥ 3 TRAEs rate was 0.59(95% CI, 0.39 to 0.77).

Conclusion

Our results revealed that the utilization of PD-1/L1 inhibitors as first-line therapy for dMMR mCRC yielded highly favorable outcomes, while maintaining an acceptable level of safety. Administering a combination of PD-1/L1 inhibitors, anti-VEGF monoclonal antibody, and chemotherapy as first-line treatment in patients with pMMR mCRC led to an improved ORR. However, there was no significant improvement in the long-term prognosis of the tumor.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024506196, identifier CRD42024506196.

Neoadjuvant Immunotherapy for Patients With Microsatellite Instability-High or POLE-Mutated Locally Advanced Colorectal Cancer With Bulky Tumors: New Optimization Strategy

OBJECTIVE

To evaluate the efficacy and safety of neoadjuvant immunotherapy for patients with microsatellite instability-high (MSI-H) or DNA polymerase ε (POLE)-mutated locally advanced colorectal cancer (LACRC) with bulky tumors.  PATIENTS: We retrospectively reviewed 22 consecutive patients with MSI-H or POLE-mutated LACRC with bulky tumors (>8 cm in diameter) who received preoperative programmed death-1 blockade, with or without CapOx chemotherapy.  MAIN OUTCOME MEASURES: Pathological complete response (pCR), clinical complete response (cCR), toxicity, R0 resection rate, and complications were evaluated. Survival outcomes were analyzed using the Kaplan-Meier method. Multiplex immunofluorescence analysis were performed before and after treatment.  RESULTS: The incidence of immune-related adverse events (irAEs) was 36.4% (8/22). Five of 22 patients presented with surgical emergencies, most commonly perforation or obstruction. The 22 patients underwent a median 4 (1-8) cycles. Two patients were evaluated as cCR and underwent a watch and wait strategy. The R0 resection rate was 100.0% (20/20) and pCR rate was 70.0% (14/20). Twelve of 14 cT4b patients (85.7%) avoided multivisceral resection, and 10 of them achieved pCR or cCR. In the two patients with POLE mutations, one each achieved pCR and cCR. No Grade III/IV postoperative complications occurred. The median follow-up was 16.0 months. Two-year event-free and overall survival for the whole cohort was both 100%.  CONCLUSIONS: Preoperative immunotherapy is the optimal option for MSI-H or POLE-mutated LACRC with bulky tumors, especially cT4b. Preoperative immunotherapy in patients with T4b CRC can reduce multivisceral resection and achieve high CR rate.

Long-term survivals of immune checkpoint inhibitors as neoadjuvant and adjuvant therapy in dMMR/MSI-H colorectal and gastric cancers

BACKGROUND

The long-term survival benefit of immune checkpoint inhibitors (ICIs) in neoadjuvant and adjuvant settings is unclear for colorectal cancers (CRC) and gastric cancers (GC) with deficiency of mismatch repair (dMMR) or microsatellite instability-high (MSI-H).

METHODS

This retrospective study enrolled patients with dMMR/MSI-H CRC and GC who received at least one dose of neoadjuvant ICIs (neoadjuvant cohort, NAC) or adjuvant ICIs (adjuvant cohort, AC) at 17 centers in China. Patients with stage IV disease were also eligible if all tumor lesions were radically resectable.

RESULTS

In NAC (n = 124), objective response rates were 75.7% and 55.4%, respectively, in CRC and GC, and pathological complete response rates were 73.4% and 47.7%, respectively. The 3-year disease-free survival (DFS) and overall survival (OS) rates were 96% (95%CI 90-100%) and 100% for CRC (median follow-up [mFU] 29.4 months), respectively, and were 84% (72-96%) and 93% (85-100%) for GC (mFU 33.0 months), respectively. In AC (n = 48), the 3-year DFS and OS rates were 94% (84-100%) and 100% for CRC (mFU 35.5 months), respectively, and were 92% (82-100%) and 96% (88-100%) for GC (mFU 40.4 months), respectively. Among the seven patients with distant relapse, four received dual blockade of PD1 and CTLA4 combined with or without chemo- and targeted drugs, with three partial response and one progressive disease.

CONCLUSION

With a relatively long follow-up, this study demonstrated that neoadjuvant and adjuvant ICIs might be both associated with promising DFS and OS in dMMR/MSI-H CRC and GC, which should be confirmed in further randomized clinical trials.

Research Advances of Lipid Nanoparticles in the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a common type of gastrointestinal tract (GIT) cancer and poses an enormous threat to human health. Current strategies for metastatic colorectal cancer (mCRC) therapy primarily focus on chemotherapy, targeted therapy, immunotherapy, and radiotherapy; however, their adverse reactions and drug resistance limit their clinical application. Advances in nanotechnology have rendered lipid nanoparticles (LNPs) a promising nanomaterial-based drug delivery system for CRC therapy. LNPs can adapt to the biological characteristics of CRC by modifying their formulation, enabling the selective delivery of drugs to cancer tissues. They overcome the limitations of traditional therapies, such as poor water solubility, nonspecific biodistribution, and limited bioavailability. Herein, we review the composition and targeting strategies of LNPs for CRC therapy. Subsequently, the applications of these nanoparticles in CRC treatment including drug delivery, thermal therapy, and nucleic acid-based gene therapy are summarized with examples provided. The last section provides a glimpse into the advantages, current limitations, and prospects of LNPs in the treatment of CRC.

Differences in the risk of immune-related pneumonitis between PD-1 and PD-L1 inhibitors: a meta-analysis according to the new mirror-principle and PRISMA guidelines

PURPOSE

To compare the risk of immune-associated pneumonitis between PD-1 and PD-L1 inhibitors, the meta-analysis was designed.

METHOD

The difference in risk of immune-associated pneumonitis between PD-1 and PD-L1 inhibitors was assessed by two different meta-analysis methods, the Mirror-pairing and the PRISMA guidelines.

RESULTS

A total of eighty-eight reports were used for meta-analysis, while thirty-two studies were used for the Mirror-pairing. Both PD-1 and PD-L1 inhibitors (used alone or combined with chemotherapy) increased the risk of developing immune-related pneumonitis (P < 0.00001; P < 0.00001). Based on indirect analyses results (subgroup analyses), the risk of PD-L1-induced pneumonitis was weaker than that of PD-1 inhibitors when the control group was chemotherapy (OR = 3.33 vs. 5.43) or placebo (OR = 2.53 vs. 3.19), while no obvious significant differences were found (P = 0.17; P = 0.53). For the Mirror-pairing-based meta-analysis, the risk of PD-1-induced pneumonitis was significantly higher than that of PD-L1 inhibitors (OR = 1.46, 95%CI [1.08, 1.98], I2 = 0%, Z = 2.47 (P = 0.01)). However, this difference was not significant, when they were combined with chemotherapy (OR = 1.05, 95%CI [0.68, 1.60], I2 = 38%, Z = 0.21 (P = 0.84)).

CONCLUSION

Both PD-1 and PD-L1 inhibitors increased the risk of immune-related pneumonitis, while the risk of PD-1-induced pneumonitis was significantly higher than that of PD-L1 inhibitors.

Efficacy and Safety of Neoadjuvant Subcutaneous Envafolimab in dMMR/MSI-H Locally Advanced Colon Cancer

BACKGROUND

Neoadjuvant immunotherapy with programmed death-ligand 1 blockade for colon cancer, especially for mismatch repair-deficient (dMMR)/high microsatellite instability (MSI-H) colon cancer, has gained considerable attention recently.

OBJECTIVE

This study aimed to assess the safety and efficacy of neoadjuvant subcutaneous envafolimab in patients with dMMR/MSI-H locally advanced colon cancer.

METHODS

Patients with dMMR/MSI-H locally advanced colon cancer treated with envafolimab at Sun Yat-sen University Cancer Center and Yunnan Cancer Hospital from October 2021 to July 2023 were retrospectively reviewed and analyzed. The primary endpoint was the pathological complete response (CR) rate, and secondary endpoints were treatment-related adverse events and complete clinical response rate.

RESULTS

Overall, 15 patients were analyzed. After neoadjuvant immunotherapy with envafolimab, six patients achieved a CR, with five partial responses, and four stable disease. Three patients achieving a complete clinical response chose to accept a "watch and wait" strategy, and surgery was performed in 12 patients. Postoperative pathology results revealed seven patients achieved pathological CRs, and five patients achieved tumor regression grade 2, with 66.7% of the total CR rate. The most common treatment-related adverse events were pruritus and rash (40%), with no severe cases. No recurrences occurred over a 7.9-month follow-up.

CONCLUSIONS

Envafolimab yielded promising surgical outcomes and safety in dMMR/MSI-H locally advanced colon cancer, representing a promising treatment modality for this population.

Advancements in combining targeted therapy and immunotherapy for colorectal cancer

Colorectal cancer (CRC) is a prevalent gastrointestinal cancer posing significant clinical challenges. CRC management traditionally involves surgery, often coupled with chemotherapy. However, unresectable or metastatic CRC (mCRC) presents a complex challenge necessitating innovative treatment strategies. Targeted therapies have emerged as the cornerstone of treatment in such cases, with interventions tailored to specific molecular attributes. Concurrently, immunotherapies have revolutionized cancer treatment by harnessing the immune system to combat malignant cells. This review explores the evolving landscape of CRC treatment, focusing on the synergy between immunotherapies and targeted therapies, thereby offering new avenues for enhancing the effectiveness of therapy for CRC.

Molecular subtypes of colorectal cancer in the era of precision oncotherapy: Current inspirations and future challenges

BACKGROUND

Colorectal cancer (CRC) is among the most hackneyed malignancies. Even patients with identical clinical symptoms and the same TNM stage still exhibit radically different clinical outcomes after receiving equivalent treatment regimens, indicating extensive heterogeneity of CRC. Myriad molecular subtypes of CRC have been exploited for decades, including the most compelling consensus molecular subtype (CMS) classification that has been broadly applied for patient stratification and biomarker-drug combination formulation. Encountering barriers to clinical translation, however, CMS classification fails to fully reflect inter- or intra-tumor heterogeneity of CRC. As a consequence, addressing heterogeneity and precisely managing CRC patients with unique characteristics remain arduous tasks for clinicians.

REVIEW

In this review, we systematically summarize molecular subtypes of CRC and further elaborate on their clinical applications, limitations, and future orientations.

CONCLUSION

In recent years, exploration of subtypes through cell lines, animal models, patient-derived xenografts (PDXs), organoids, and clinical trials contributes to refining biological insights and unraveling subtype-specific therapies in CRC. Therapeutic interventions including nanotechnology, clustered regulatory interspaced short palindromic repeat/CRISPR-associated nuclease 9 (CRISPR/Cas9), gut microbiome, and liquid biopsy are powerful tools with the possibility to shift the immunologic landscape and outlook for CRC precise medicine.

Randomized Phase II Trial of Immunotherapy-Based Total Neoadjuvant Therapy for Proficient Mismatch Repair or Microsatellite Stable Locally Advanced Rectal Cancer (TORCH)

PURPOSE

To assess whether the integration of PD-1 inhibitor with total neoadjuvant therapy (iTNT) can lead to an improvement in complete responses (CRs) and favors a watch-and-wait (WW) strategy in patients with proficient mismatch repair or microsatellite stable (pMMR/MSS) locally advanced rectal cancer (LARC).

PATIENTS AND METHODS

We conducted a prospective, multicenter, randomized, open-label, phase II trial using a pick-the-winner design. Eligible patients with clinical T3-4 and/or N+ rectal adenocarcinoma were randomly assigned to group A for short-course radiotherapy (SCRT) followed by six cycles of consolidation immunochemotherapy with capecitabine and oxaliplatin and toripalimab or to group B for two cycles of induction immunochemotherapy followed by SCRT and the rest four doses. Either total mesorectal excision or WW was applied on the basis of tumor response. The primary end point was CR which included pathological CR (pCR) after surgery and clinical CR (cCR) if WW was applicable, with hypothesis of an increased CR of 40% after iTNT compared with historical data of 25% after conventional TNT.

RESULTS

Of the 130 patients enrolled, 121 pMMR/MSS patients were evaluable (62 in group A and 59 in group B). At a median follow-up of 19 months, CR was achieved at 56.5% in group A and 54.2% in group B. Both groups fulfilled the predefined statistical hypothesis (P < .001). Both groups reported a pCR rate of 50%. Respectively, 15 patients in each group underwent WW and remained disease free. The most frequent grade 3 to 4 toxicities were thrombocytopenia and neutropenia. Patients in group A had higher rate of cCR (43.5% v 35.6%) at restaging and lower rate of grade 3 to 4 thrombocytopenia (24.2% v 33.9%) during neoadjuvant treatment.

CONCLUSION

The iTNT regimens remarkably improved CR rates in pMMR/MSS LARC compared with historical benchmark with acceptable toxicity. Up-front SCRT followed by immunochemotherapy was selected for future definitive study.

A comprehensive overview of the molecular features and therapeutic targets in BRAFV600E-mutant colorectal cancer

As one of the most prevalent digestive system tumours, colorectal cancer (CRC) poses a significant threat to global human health. With the emergence of immunotherapy and target therapy, the prognosis for the majority of CRC patients has notably improved. However, the subset of patients with BRAF exon 15 p.V600E mutation (BRAFV600E) has not experienced remarkable benefits from these therapeutic advancements. Hence, researchers have undertaken foundational investigations into the molecular pathology of this specific subtype and clinical effectiveness of diverse therapeutic drug combinations. This review comprehensively summarised the distinctive molecular features and recent clinical research advancements in BRAF-mutant CRC. To explore potential therapeutic targets, this article conducted a systematic review of ongoing clinical trials involving patients with BRAFV600E-mutant CRC.

Defining clinically useful biomarkers of immune checkpoint inhibitors in solid tumours

Although more than a decade has passed since the approval of immune checkpoint inhibitors (ICIs) for the treatment of melanoma and non-small-cell lung, breast and gastrointestinal cancers, many patients still show limited response. US Food and Drug Administration (FDA)-approved biomarkers include programmed cell death 1 ligand 1 (PDL1) expression, microsatellite status (that is, microsatellite instability-high (MSI-H)) and tumour mutational burden (TMB), but these have limited utility and/or lack standardized testing approaches for pan-cancer applications. Tissue-based analytes (such as tumour gene signatures, tumour antigen presentation or tumour microenvironment profiles) show a correlation with immune response, but equally, these demonstrate limited efficacy, as they represent a single time point and a single spatial assessment. Patient heterogeneity as well as inter- and intra-tumoural differences across different tissue sites and time points represent substantial challenges for static biomarkers. However, dynamic biomarkers such as longitudinal biopsies or novel, less-invasive markers such as blood-based biomarkers, radiomics and the gut microbiome show increasing potential for the dynamic identification of ICI response, and patient-tailored predictors identified through neoadjuvant trials or novel ex vivo tumour models can help to personalize treatment. In this Perspective, we critically assess the multiple new static, dynamic and patient-specific biomarkers, highlight the newest consortia and trial efforts, and provide recommendations for future clinical trials to make meaningful steps forwards in the field.

Advancements in the Management of Synchronous Colorectal Liver Metastases: A Comprehensive Review of Surgical, Systemic, and Local Treatment Modalities

PURPOSE OF REVIEW

This review addresses the current landscape of colorectal cancer (CRC) with a focus on liver metastases, the third most common cancer globally. It explores recent findings in treatment strategies, emphasizing the dynamic interplay between surgery, systemic chemotherapy, and local therapies for synchronous colorectal liver metastases (CRLMs).

RECENT FINDINGS

Highlighting the role of advanced imaging, the review underscores the significance of contrast-enhanced MRI in surgical planning for CRLMs. Surgical resection remains a primary choice for resectable cases, with considerations for oncologic scoring systems and tumor biology. Perioperative systemic chemotherapy plays a pivotal role, especially in conversion therapy for initially unresectable CRLMs. The review also explores various local therapies, including radiofrequency ablation, microwave ablation, stereotactic body radiotherapy, hepatic arterial infusional chemotherapy, selective internal radiation therapy, and transarterial chemoembolization for unresectable cases. A comprehensive approach, integrating surgery, systemic chemotherapy, and local therapies, is crucial for managing synchronous CRLMs. Surgical resection and perioperative chemotherapy are key players, guided by considerations of tumor biology and scoring systems. For unresectable cases, local therapies offer viable alternatives, emphasizing the need for tailored treatments. Multidisciplinary collaboration among medical oncologists, surgeons, and radiologists is essential. Ongoing research will refine treatment approaches, while emerging technologies hold promise for further advancements in managing colorectal liver metastases.

Non-operative management after immune checkpoint inhibitors for early-stage, dMMR/MSI-H gastrointestinal cancers

Surgery is a standard treatment for early-stage gastrointestinal cancers, often preceded by neoadjuvant chemo(radio)therapy or followed by adjuvant therapy. While leading to cure in a proportion of patients, it has some drawbacks such as intra/post-operative complications, mutilation and life-long functional sequelae. Further to the unprecedented efficacy data from studies of immune checkpoint inhibitors for advanced mismatch repair deficient/microsatellite instable (dMMR/MSI-H) tumours, a strong interest has recently emerged for the investigation of such agents in the neoadjuvant setting. Although limited by the exploratory design and small sample size, trials of neoadjuvant immune checkpoint inhibitors for early-stage dMMR/MSI-H gastrointestinal cancers have consistently reported complete response rates ranging from 70 % to 100 %. As a result, the question has arisen as to whether surgery is still needed or organ-preserving strategies should be offered to this especially immuno-sensitive population. In this article, we discuss the available evidence for neoadjuvant immune checkpoint inhibitors in dMMR/MSI-H gastrointestinal cancers and analyse opportunities and challenges to the implementation of non-operative management approaches in this setting.

Circadian control of tumor immunosuppression affects efficacy of immune checkpoint blockade

The circadian clock is a critical regulator of immunity, and this circadian control of immune modulation has an essential function in host defense and tumor immunosurveillance. Here we use a single-cell RNA sequencing approach and a genetic model of colorectal cancer to identify clock-dependent changes to the immune landscape that control the abundance of immunosuppressive cells and consequent suppression of cytotoxic CD8+ T cells. Of these immunosuppressive cell types, PD-L1-expressing myeloid-derived suppressor cells (MDSCs) peak in abundance in a rhythmic manner. Disruption of the epithelial cell clock regulates the secretion of cytokines that promote heightened inflammation, recruitment of neutrophils and the subsequent development of MDSCs. We also show that time-of-day anti-PD-L1 delivery is most effective when synchronized with the abundance of immunosuppressive MDSCs. Collectively, these data indicate that circadian gating of tumor immunosuppression informs the timing and efficacy of immune checkpoint inhibitors.

Challenges and Opportunities for Precision Surgery for Colorectal Liver Metastases

The incidence of colorectal cancer and colorectal liver metastases (CRLM) is increasing globally due to an interaction of environmental and genetic factors. A minority of patients with CRLM have surgically resectable disease, but for those who have resection as part of multimodal therapy for their disease, long-term survival has been shown. Precision surgery-the idea of careful patient selection and targeting of surgical intervention, such that treatments shown to be proven to benefit on a population level are the optimal treatment for each individual patient-is the new paradigm of care. Key to this is the understanding of tumour molecular biology and clinically relevant mutations, such as KRAS, BRAF, and microsatellite instability (MSI), which can predict poorer overall outcomes and a poorer response to systemic therapy. The emergence of immunotherapy and hepatic artery infusion (HAI) pumps show potential to convert previously unresectable disease to resectable disease, in addition to established systemic and locoregional therapies, but the surgeon must be wary of poor-quality livers and the spectre of post-hepatectomy liver failure (PHLF). Volume modulation, a cornerstone of hepatic surgery for a generation, has been given a shot in the arm with the advent of liver venous depletion (LVD) ensuring significantly more hypertrophy of the future liver remnant (FLR). The optimal timing of liver resection for those patients with synchronous disease is yet to be truly established, but evidence would suggest that those patients requiring complex colorectal surgery and major liver resection are best served with a staged approach. In the operating room, parenchyma-preserving minimally invasive surgery (MIS) can dramatically reduce the surgical insult to the patient and lead to better perioperative outcomes, with quicker return to function.

The tumor immune microenvironment and T-cell-related immunotherapies in colorectal cancer

The tumor microenvironment includes a complex network of immune T-cell subsets that play important roles in colorectal cancer (CRC) progression and are key elements of CRC immunotherapy. T cells develop and migrate within tumors, recognizing tumor-specific antigens to regulate immune surveillance. Current immunotherapies are divided into the following main categories based on the regulatory role of T-cell subsets in the tumor immune microenvironment (TIME): cytokines, monoclonal antibodies, peptide vaccines, CAR-T cells and more. This review describes the composition of the tumor immune microenvironment in colorectal cancer and the involvement of T cells in the pathogenesis and progression of CRC as well as current T-cell-related immunotherapies. Further studies on CRC-specific tumor antigens, the gene regulation of T cells, and the regulation of immune activity are needed.

Critical Appraisal and Future Challenges of Artificial Intelligence and Anticancer Drug Development

The conventional rules for anti-cancer drug development are no longer sufficient given the relatively limited number of patients available for therapeutic trials. It is thus a real challenge to better design trials in the context of new drug approval for anti-cancer treatment. Artificial intelligence (AI)-based in silico trials can incorporate far fewer but more informative patients and could be conducted faster and at a lower cost. AI can be integrated into in silico clinical trials to improve data analysis, modeling and simulation, personalized medicine approaches, trial design optimization, and virtual patient generation. Health authorities are encouraged to thoroughly review the rules for setting up clinical trials, incorporating AI and in silico methodology once they have been appropriately validated. This article also aims to highlight the limits and challenges related to AI and machine learning.

Imaging in the era of risk-adapted treatment in colon cancer

The treatment landscape for patients with colon cancer is continuously evolving. Risk-adapted treatment strategies, including neoadjuvant chemotherapy and immunotherapy, are slowly finding their way into clinical practice and guidelines. Radiologists are pivotal in guiding clinicians toward the most optimal treatment for each colon cancer patient. This review provides an overview of recent and upcoming advances in the diagnostic management of colon cancer and the radiologist's role in the multidisciplinary approach to treating colon cancer.

First-line serplulimab in metastatic colorectal cancer: Phase 2 results of a randomized, double-blind, phase 2/3 trial

BACKGROUND

Whether or not the addition of immunotherapy to current standard-of-care treatments can improve efficacy in proficient mismatch repair (pMMR)/microsatellite-stable (MSS) metastatic colorectal cancer (mCRC), the predominant type of mCRC, is unclear.

METHODS

This randomized, double-blind, phase 2 part of a phase 2/3 trial was conducted at 23 hospitals across China (ClinicalTrials.gov: NCT04547166). Patients with unresectable metastatic/recurrent colorectal adenocarcinoma and no prior systemic therapy were randomly assigned 1:1 to receive every-3-weeks intravenous serplulimab (300 mg) plus HLX04 (7.5 mg/kg) and XELOX (serplulimab group) or placebo (300 mg) plus bevacizumab (7.5 mg/kg) and XELOX (placebo group). The primary endpoint was independent radiology review committee (IRRC)-assessed progression-free survival (PFS). Secondary endpoints included other efficacy endpoints and safety.

FINDINGS

Between July 16, 2021, and January 20, 2022, 114 patients were enrolled and randomly assigned to the serplulimab (n = 57) or placebo (n = 57) group. All patients had stage IV CRC, and 95.7% of the patients with available microsatellite instability (MSI) status were MSS. With a median follow-up duration of 17.7 months, median PFS was prolonged in the serplulimab group (17.2 vs. 10.7 months; hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.31-1.14). Although the median overall survival (OS) was not reached for either group, a trend of an OS benefit was observed for the serplulimab group (HR, 0.77; 95% CI, 0.41-1.45). 36 (65.5%) and 32 (56.1%) patients in the serplulimab and placebo groups had grade ≥3 treatment-related adverse events, respectively.

CONCLUSIONS

Serplulimab plus HLX04 and XELOX exhibits promising efficacy and is safe and tolerable in patients with treatment-naive mCRC.

FUNDING

This work was funded by Shanghai Henlius Biotech, Inc.

Transient TCR-based T cell therapy in a patient with advanced treatment-resistant MSI-high colorectal cancer

We previously demonstrated the antitumor effectiveness of transiently T cell receptor (TCR)-redirected T cells recognizing a frameshift mutation in transforming growth factor beta receptor 2. We here describe a clinical protocol using mRNA TCR-modified T cells to treat a patient with progressive, treatment-resistant metastatic microsatellite instability-high (MSI-H) colorectal cancer. Following 12 escalating doses of autologous T cells electroporated with in-vitro-transcribed Radium-1 TCR mRNA, we assessed T cell cytotoxicity, phenotype, and cytokine production. Tumor markers and growth on computed tomography scans were evaluated and immune cell tumor infiltrate at diagnosis assessed. At diagnosis, tumor-infiltrating CD8+ T cells had minimal expression of exhaustion markers, except for PD-1. Injected Radium-1 T cells were mainly naive and effector memory T cells with low expression of exhaustion markers, except for TIGIT. We confirmed cytotoxicity of transfected Radium-1 T cells against target cells and found key cytokines involved in tumor metastasis, growth, and angiogenesis to fluctuate during treatment. The treatment was well tolerated, and despite his advanced cancer, the patient obtained a stable disease with 6 months survival post-treatment. We conclude that treatment of metastatic MSI-H colorectal cancer with autologous T cells electroporated with Radium-1 TCR mRNA is feasible, safe, and well tolerated and that it warrants further investigation in a phase 1/2 study.

Inhibition of glycolysis enhances the efficacy of immunotherapy via PDK-mediated upregulation of PD-L1

BACKGROUND

Immunotherapy for gastric cancer remains a challenge due to its limited efficacy. Metabolic reprogramming toward glycolysis has emerged as a promising avenue for enhancing the sensitivity of tumors to immunotherapy. Pyruvate dehydrogenase kinases (PDKs) play pivotal roles in regulating glycolysis. The importance of PDKs in the context of gastric cancer immunotherapy and their potential as therapeutic targets have not been fully explored.

METHODS

PDK and PD-L1 expression was analyzed using data from the GSE66229 and The Cancer Genome Atlas (TCGA) cohorts. Additionally, the Immune Checkpoint Blockade Therapy Atlas (ICBatlas) database was utilized to assess PDK expression in an immune checkpoint blockade (ICB) therapy group. Subsequently, the upregulation of PD-L1 and the enhancement of anticancer effects achieved by targeting PDK were validated through in vivo and in vitro assays. The impact of PDK on histone acetylation was investigated using ChIP‒qPCR to detect changes in histone acetylation levels.

RESULTS

Our analysis revealed a notable negative correlation between PD-L1 and PDK expression. Downregulation of PDK led to a significant increase in PD-L1 expression. PDK inhibition increased histone acetylation levels by promoting acetyl-CoA generation. The augmentation of acetyl-CoA production and concurrent inhibition of histone deacetylation were found to upregulate PD-L1 expression in gastric cancer cells. Additionally, we observed a significant increase in the anticancer effect of PD-L1 antibodies following treatment with a PDK inhibitor.

CONCLUSIONS

Downregulation of PDK in gastric cancer cells leads to an increase in PD-L1 expression levels, thus potentially improving the efficacy of PD-L1 immune checkpoint blockade therapy.

Early Changes in Tumor-Naive Cell-Free Methylomes and Fragmentomes Predict Outcomes in Pembrolizumab-Treated Solid Tumors

Early kinetics of circulating tumor DNA (ctDNA) in plasma predict response to pembrolizumab but typically requires sequencing of matched tumor tissue or fixed gene panels. We analyzed genome-wide methylation and fragment-length profiles using cell-free methylated DNA immunoprecipitation and sequencing (cfMeDIP-seq) in 204 plasma samples from 87 patients before and during treatment with pembrolizumab from a pan-cancer phase II investigator-initiated trial (INSPIRE). We trained a pan-cancer methylation signature using independent methylation array data from The Cancer Genome Atlas to quantify cancer-specific methylation (CSM) and fragment-length score (FLS) for each sample. CSM and FLS are strongly correlated with tumor-informed ctDNA levels. Early kinetics of CSM predict overall survival and progression-free survival, independently of tumor type, PD-L1, and tumor mutation burden. Early kinetics of FLS are associated with overall survival independently of CSM. Our tumor-naïve mutation-agnostic ctDNA approach integrating methylomics and fragmentomics could predict outcomes in patients treated with pembrolizumab.

SIGNIFICANCE

Analysis of methylation and fragment length in plasma using cfMeDIP-seq provides a tumor-naive approach to measure ctDNA with results comparable with a tumor-informed bespoke ctDNA. Early kinetics within the first weeks of treatment in methylation and fragment quantity can predict outcomes with pembrolizumab in patients with various advanced solid tumors. This article is featured in Selected Articles from This Issue, p. 897.

Treatment strategies and molecular mechanism of radiotherapy combined with immunotherapy in colorectal cancer

Radiotherapy (RT) remodels the tumor immune microenvironment (TIME) and modulates the immune response to indirectly destroy tumor cells, in addition to directly killing tumor cells. RT combined with immunotherapy may significantly enhance the efficacy of RT in colorectal cancer by modulating the microenvironment. However, the molecular mechanisms by which RT acts as an immunomodulator to modulate the immune microenvironment remain unclear. Further, the optimal modalities of RT combined with immunotherapy for the treatment of colorectal cancer, such as the time point of combining RT and immunization, the fractionation pattern and dosage of radiotherapy, and other methods to improve the efficacy, are also being explored parallelly. To address these aspects, in this review, we summarized the mechanisms by which RT modulates TIME and concluded the progress of RT combined with immunization in preclinical and clinical trials. Finally, we discussed heavy ion radiation therapy and the efficacy of prediction markers and other immune combination therapies. Overall, combining RT with immunotherapy to enhance antitumor effects will have a significant clinical implication and will help to facilitate individualized treatment modalities.

Pembrolizumab Plus Binimetinib With or Without Chemotherapy for MSS/pMMR Metastatic Colorectal Cancer: Outcomes From KEYNOTE-651 Cohorts A, C, and E

BACKGROUND

Cohorts A, C, and E of the phase Ib KEYNOTE-651 study evaluated pembrolizumab + binimetinib ± chemotherapy in microsatellite stable/mismatch repair-proficient metastatic colorectal cancer.

PATIENTS AND METHODS

Patients received pembrolizumab 200 mg every 3 weeks plus binimetinib 30 mg twice daily alone (cohort A; previously treated with any chemotherapy) or with 5-fluorouracil, leucovorin, oxaliplatin (cohort C; previously untreated) or 5-fluorouracil, leucovorin, irinotecan (cohort E; previously treated with 1 line of therapy including fluoropyrimidine + oxaliplatin-based regimen) every 2 weeks. Binimetinib dose-escalation to 45 mg twice daily was planned in all cohorts using a modified toxicity probability interval design (target dose-limiting toxicity [DLT], 30%). The primary endpoint was safety; investigator-assessed objective response rate was secondary.

RESULTS

In cohort A, 1/6 patients (17%) had DLTs with binimetinib 30 mg; none occurred in 14 patients with 45 mg. In cohort C, 3/9 patients (33%) had DLTs with binimetinib 30 mg; dose was not escalated to 45 mg. In cohort E, 1/5 patients (20%) had DLTs with binimetinib 30 mg; 5/10 patients (50%) had DLTs with 45 mg. Enrollment was stopped in cohort E binimetinib 45 mg and deescalated to 30 mg; 2/4 additional patients (50%) had DLTs with binimetinib 30 mg (total 3/9 [33%] had DLTs with binimetinib 30 mg). Objective response rate was 0% in cohort A, 9% in cohort C, and 15% in cohort E.

CONCLUSION

Per DLT criteria, binimetinib + pembrolizumab (cohort A) was tolerable, binimetinib + pembrolizumab + 5-fluorouracil, leucovorin, oxaliplatin (cohort C) did not qualify for binimetinib dose escalation to 45 mg, and binimetinib + pembrolizumab + 5-fluorouracil, leucovorin, irinotecan (cohort E) required binimetinib dose reduction from 45 to 30 mg. No new safety findings were observed across cohorts. There was no apparent additive efficacy when binimetinib + pembrolizumab was added to chemotherapy. Data did not support continued enrollment in cohorts C and E.

Systematic Review of Neoadjuvant Immunotherapy for Mismatch Repair Deficient Locally Advanced Colon Cancer: An Emerging Strategy

BACKGROUND

In April 2023, the National Comprehensive Cancer Network endorsed neoadjuvant immunotherapy for select patients with nonmetastatic mismatch repair deficient colon cancer. Approximately 15% of incident colon cancers are mismatch repair deficient, resulting in a distinct molecular subtype with high microsatellite instability that is responsive to immune checkpoint inhibition.

OBJECTIVE

To describe the existing evidence supporting neoadjuvant immunotherapy for mismatch repair deficient, microsatellite unstable nonmetastatic colon cancer.

DATA SOURCES

A medical librarian performed PubMed, Embase, and Web of Science searches most recently on April 24, 2023. The PubMed search was re-run on September 26, 2023, to identify any additional studies published between April 24 and September 26, 2023.

STUDY SELECTION

Two authors screened titles and abstracts in the published studies. The inclusion criteria were 1) English language, 2) adults with primary cancer of the colon, 3) nonmetastatic disease, 4) neoadjuvant immunotherapy, and 5) reporting on 10 or more cases.

INTERVENTION

Neoadjuvant immunotherapy.

MAIN OUTCOME MEASURES

Safety (grade 3+ treatment-related adverse events) and efficacy (complete pathologic responses).

RESULTS

From 7691 studies identified, 6370 were screened and 8 were included. Various agents, dosing regimens, and treatment durations were used, with durations of immunotherapy ranging from 1 to 16 cycles. Complete R0 resections were consistently achieved in 98% to 100% of resections. Of patients who received neoadjuvant immunotherapy and underwent resection, 50% to 91% had ypT0N0 pathology. The safety profiles were generally favorable, with grade 1 to 2 treatment-related adverse events (mostly immune-related) during immunotherapy reported in 22.2% to 70% of patients. Postoperative complications after neoadjuvant immunotherapy were reassuring, with no severe complications reported.

LIMITATIONS

Small number of heterogeneous and uncontrolled studies precluding a meta-analysis.

CONCLUSIONS

Neoadjuvant immune checkpoint inhibition is associated with high rates of pathologic complete responses in locally advanced colon cancer. The literature is limited, particularly for postoperative outcomes, and more studies are needed to understand the safety and positioning of these regimens in the neoadjuvant context.

Microsatellite instability: A 2024 update

Deficient mismatch repair (dMMR) results in microsatellite instability (MSI), a pronounced mutator phenotype. High-frequency MSI (MSI-H)/dMMR is gaining increasing interest as a biomarker for advanced cancer patients to determine their eligibility for immune checkpoint inhibitors (ICIs). Various methods based on next-generation sequencing (NGS) have been developed to assess the MSI status. Comprehensive genomic profiling (CGP) testing can precisely ascertain the MSI status as well as genomic alterations in a single NGS test. The MSI status can be also ascertained through the liquid biopsy-based CGP assays. MSI-H has thus been identified in various classes of tumors, resulting in a greater adoption of immunotherapy, which is hypothesized to be effective against malignancies that possess a substantial number of mutations and/or neoantigens. NGS-based studies have also characterized MSI-driven carcinogenesis, including significant rates of fusion kinases in colorectal cancers (CRCs) with MSI-H that are targets for therapeutic kinase inhibitors, particularly in MLH1-methylated CRCs with wild-type KRAS/BRAF. NTRK fusion is linked to the colorectal serrated neoplasia pathway. Recent advances in investigations of MSI-H malignancies have resulted in the development of novel diagnostic or therapeutic techniques, such as a synthetic lethal therapy that targets the Werner gene. DNA sensing in cancer cells is required for antitumor immunity induced by dMMR, opening up novel avenues and biomarkers for immunotherapy. Therefore, clinical relevance exists for analyses of MSI and MSI-H-associated genomic alterations in malignancy. In this article, we provide an update on MSI-driven carcinogenesis, with an emphasis on unique landscapes of diagnostic and immunotherapeutic strategies.

Pembrolizumab Plus mFOLFOX7 or FOLFIRI for Microsatellite Stable/Mismatch Repair-Proficient Metastatic Colorectal Cancer: KEYNOTE-651 Cohorts B and D

BACKGROUND

The phase 1b KEYNOTE-651 study evaluated pembrolizumab plus chemotherapy in microsatellite stable or mismatch repair-proficient metastatic colorectal cancer.

PATIENTS AND METHODS

Patients with microsatellite stable or mismatch repair-proficient metastatic colorectal cancer received pembrolizumab 200 mg every 3 weeks plus 5-fluorouracil, leucovorin, oxaliplatin (previously untreated; cohort B) or 5-fluorouracil, leucovorin, irinotecan (previously treated with fluoropyrimidine plus oxaliplatin; cohort D) every 2 weeks. Primary end point was safety; investigator-assessed objective response rate per RECIST v1.1 was secondary and biomarker analysis was exploratory.

RESULTS

Thirty-one patients were enrolled in cohort B and 32 in cohort D; median follow-up was 30.2 and 33.5 months, respectively. One dose-limiting toxicity (grade 3 small intestine obstruction) occurred in cohort D. In cohort B, grade 3 or 4 treatment-related adverse events (AEs) occurred in 18 patients (58%), most commonly neutropenia and decreased neutrophil count (n = 5 each). In cohort D, grade 3 or 4 treatment-related AEs occurred in 17 patients (53%), most commonly neutropenia (n = 7). No grade 5 treatment-related AEs occurred. Objective response rate was 61% in cohort B (KRAS wildtype: 71%; KRAS mutant: 53%) and 25% in cohort D (KRAS wildtype: 47%; KRAS mutant: 6%). In both cohorts, PD-L1 combined positive score and T-cell-inflamed gene expression profiles were higher and HER2 expression was lower in responders than nonresponders. No association between tumor mutational burden and response was observed.

CONCLUSION

Pembrolizumab plus 5-fluorouracil, leucovorin, oxaliplatin/5-fluorouracil, leucovorin, irinotecan demonstrated an acceptable AE profile. Efficacy data appeared comparable with current standard of care (including by KRAS mutation status). Biomarker analyses were hypothesis-generating, warranting further exploration.

CLINICALTRIALS

GOV IDENTIFIER

ClinicalTrials.gov; NCT03374254.

Conversion therapy with pembrolizumab for a peritoneal metastasis of rectal cancer causing hydronephrosis in a patient with Lynch syndrome

A 44-year-old woman with Lynch syndrome was referred to our hospital for treatment of recurrence of microsatellite instability-high rectal cancer. [18F]Fluorodeoxyglucose (18FDG)-positron emission tomography revealed a peritoneal metastasis with invasion to the small intestine and left ureter. The peritoneal metastasis was diagnosed initially as unresectable because of extensive invasion to the left ureter requiring nephrectomy. Hence, first-line treatment with pembrolizumab was started. After the first course of pembrolizumab, she developed hydronephrosis and a resulting urinary tract infection (UTI). A percutaneous nephrostomy was performed to control the UTI. After six courses of pembrolizumab, 18FDG-positron emission tomography showed that the peritoneal metastasis was smaller with significantly reduced 18FDG uptake, and it was then diagnosed as resectable without nephrectomy. She underwent R0 resection of the peritoneal metastasis with partial resection of the small intestine. Intraoperatively, the peritoneal metastasis showed no invasion of the left ureter, allowing its preservation. The percutaneous nephrostomy was removed postoperatively, and she has not developed any subsequent UTIs. Histopathologically, the tumor showed a pathological complete response to pembrolizumab. To the best of our knowledge, this is the first case of conversion therapy with pembrolizumab for peritoneal metastasis with hydronephrosis.

State-of-the-Art Management of Colorectal Cancer: Treatment Advances and Innovation

Colorectal cancer (CRC) remains a significant global health challenge, ranking among the leading causes of cancer-related morbidity and mortality worldwide. Recent advancements in molecular characterization have revolutionized our understanding of the heterogeneity within colorectal tumors, particularly in the context of tumor sidedness. Tumor sidedness, referring to the location of the primary tumor in either the right or left colon, has emerged as a critical factor influencing prognosis and treatment responses in metastatic CRC. Molecular underpinnings of CRC, the impact of tumor sidedness, and how this knowledge guides therapeutic decisions in the era of precision medicine have led to improved outcomes and better quality of life in patients. The emergence of circulating tumor DNA as a prognostic and predictive tool in CRC heralds promising advancements in the diagnosis and monitoring of the disease. This innovation facilitates better patient selection for exploration of additional treatment options. As the field progresses, with investigational agents demonstrating potential as future treatments for refractory metastatic CRC, new avenues for enhancing outcomes in this challenging disease are emerging.

Immunotherapy in Colorectal Cancer - Finding the Achilles' Heel

AbstractColorectal cancer treatment has evolved considerably in the last decade with the development of immunotherapies. Immune checkpoint inhibitor therapies have brisk and durable responses in patients with advanced microsatellite instability-high colorectal cancer, both surgically resectable and unresectable; however, patients with microsatellite stable colorectal cancer in general do not respond to the same therapy. Emerging evidence shows that immune checkpoint inhibitors may elicit responses in subsets of patients with microsatellite stable colorectal cancer, especially when combined with other anticancer agents that can modulate the tumor microenvironment. Therefore, rationally designed therapeutic combinations involving immune checkpoint inhibitors, as well as the development of predictive biomarkers for optimal patient selection, have emerged as two key areas of active research. In addition, other immunotherapeutic agents such as cell-based therapies and bispecific T-cell engagers are beginning to be studied in preclinical and early-phase settings. Although by no means a universal treatment strategy, immunotherapy can elicit responses in microsatellite stable colorectal cancer and further research is needed to extend their benefit to patients with microsatellite stable colorectal cancer. Here, we review the current state of immunotherapeutic regimens for microsatellite stable colorectal cancer.

A collaborative review of the microsatellite instability/deficient mismatch repair phenotype in patients with upper tract urothelial carcinoma

OBJECTIVE

To perform a collaborative review of the literature exploring the microsatellite instability/deficient mismatch repair (MSI/dMMR) phenotype in patients with upper tract urothelial carcinoma (UTUC).

METHOD

A collaborative review of the literature available on Medline was conducted by the Cancer Committee of the French Association of Urology to report studies describing the genetic mechanisms, investigation, prevalence and impact of the MSI/dMMR phenotype in UTUC patients.

RESULTS

The predominant genetic mechanism leading to the MSI/dMMR phenotype in UTUC patients is related to the constitutional mutation of one allele of the MMR genes MLH1, MSH2, MSH6 and PMS2 within Lynch syndrome. Indications for its investigation currently remain limited to patients with a clinical suspicion for sporadic UTUC to refer only those with a positive testing for germline DNA sequencing to screen for this syndrome. With regard to technical aspects, despite the interest of MSIsensor, only PCR and immunohistochemistry are routinely used to somatically investigate the MSI and dMMR phenotypes, respectively. The prevalence of the MSI/dMMR phenotype in UTUC patients ranges from 1.7% to 57%, depending on the study population, investigation method and definition of a positive test. Younger age and a more balanced male to female ratio at initial diagnosis are the main specific clinical characteristics of UTUC patients with an MSI/dMMR phenotype. Despite the conflicting results available in the literature, these patients may have a better prognosis, potentially related to more favourable pathological features. Finally, they may also have lower sensitivity to chemotherapy but greater sensitivity to immunotherapy.

CONCLUSION

Our collaborative review summarises the available data from published studies exploring the MSI/dMMR phenotype in UTUC patients, the majority of which are limited by a low level of evidence.