Immunotherapy in colorectal cancer: is the long-awaited revolution finally happening?

Homologous recombination deficiency and immunotherapy response in microsatellite-stable colorectal cancer: Evidence from a cohort study in China

BACKGROUND

Patients with colorectal cancer (CRC) exhibiting microsatellite instability (MSI)-high generally demonstrate a favorable response to immunotherapy. In contrast, the efficacy of immunotherapy in microsatellite-stable (MSS) CRC patients is considerably restricted. This study sought to evaluate the effectiveness of immunotherapy in MSS patients characterized by homologous recombination deficiency (HRD) as opposed to those with homologous recombination proficiency (HRP).

AIM

To investigate and compare the clinicopathological characteristics, treatment modalities, and outcomes between the HRD and HRP groups in CRC.

METHODS

Next-generation sequencing was performed on 268 CRC patients to identify tumor-associated genetic alterations and assess their HRD scores and MSI status. Patients with HRD-related gene alterations or an HRD score ≥ 30 were classified into the HRD group, while the remaining patients were assigned to the HRP group. Clinical data, including staging and treatment regimens, were collected for analysis. Cox regression and Kaplan-Meier survival curves were employed to evaluate whether the HRD group demonstrated improved survival outcomes following immunotherapy treatment.

RESULTS

Among the 268 patients, 64 were classified into the HRD group, which had a higher proportion of early-stage CRC diagnoses compared to the HRP group. Kaplan-Meier survival curves indicated significantly better survival rates in the HRD group compared to the HRP group across all cohorts, as well as among MSS patients treated with immunotherapy (P < 0.05).

CONCLUSION

This study demonstrates that CRC patients with HRD have a more favorable prognosis and suggests that HRD status could serve as a predictive marker for immunotherapy response in MSS patients.

Navigating through novelties concerning mCRC treatment-the role of immunotherapy, chemotherapy, and targeted therapy in mCRC

Over the course of nearly six decades since the inception of initial trials involving 5-FU in the treatment of mCRC (metastatic colorectal cancer), our progressive comprehension of the pathophysiology, genetics, and surgical techniques related to mCRC has paved the way for the introduction of novel therapeutic modalities. These advancements not only have augmented the overall survival but have also positively impacted the quality of life (QoL) for affected individuals. Despite the remarkable progress made in the last two decades in the development of chemotherapy, immunotherapy, and target therapies, mCRC remains an incurable disease, with a 5-year survival rate of 14%. In this comprehensive review, our primary goal is to present an overview of mCRC treatment methods following the latest guidelines provided by the National Comprehensive Cancer Network (NCCN), the American Society of Clinical Oncology (ASCO), and the American Society of Colon and Rectal Surgeons (ASCRS). Emphasis has been placed on outlining treatment approaches encompassing chemotherapy, immunotherapy, targeted therapy, and surgery's role in managing mCRC. Furthermore, our review delves into prospective avenues for developing new therapies, offering a glimpse into the future of alternative pathways that hold potential for advancing the field.

Immunocheckpoint Inhibitors in Microsatellite-Stable or Proficient Mismatch Repair Metastatic Colorectal Cancer: Are We Entering a New Era?

Colorectal cancer (CRC) is the third most frequent cancer and the second leading cause of cancer-related deaths in Europe. About 5% of metastatic CRC (mCRC) are characterized by high microsatellite instability (MSI) due to a deficient DNA mismatch repair (dMMR), and this condition has been related to a high sensitivity to immunotherapy, in particular to the Immune Checkpoint Inhibitors (ICIs). In fact, in MSI-H or dMMR mCRC, treatment with ICIs induced remarkable response rates and prolonged survival. However, the majority of mCRC cases are mismatch-repair-proficient (pMMR) and microsatellite-stable (MSS), and unfortunately these conditions involve resistance to ICIs. This review aims to provide an overview of the strategies implemented to overcome ICI resistance and/or define subgroups of patients with MSS or dMMR mCRC who may benefit from immunotherapy.

Hilar/mediastinal and cutaneous drug-induced sarcoidosis-like reaction associated with immune checkpoint inhibitors in metastatic colorectal cancer: a case report

Background

Immune checkpoint inhibitors (ICIs) are the standard treatment for metastatic colorectal cancer (mCRC) with high microsatellite instability (MSI-H). Among immune-related adverse events (irAEs), drug-induced sarcoidosis-like reactions (DISR) are often difficult to differentiate from cancer progression.

Main Body

This is a case of a woman in her mid-60s, with mCRC (RAS wild/BRAF mutant/MSI-H) and abdominal lymph node metastasis, treated with four courses of ipilimumab + nivolumab every 3 weeks, followed by nivolumab every 2 weeks as third-line treatment. After treatment, the original lymph node metastases shrank, but hilar/mediastinal lymph nodes appeared. Endoscopic ultrasound-guided fine-needle aspiration of these lymph nodes revealed multiple epithelioid granulomas without necrosis, indicating a sarcoidosis-like reaction. Fluorodeoxyglucose-positron emission tomography scan showed abnormal subcutaneous accumulation in bilateral forearms and bilateral knee joints. Biopsy of the cutaneous lesions was also performed, which revealed epithelioid granulomas. As the patient had no symptoms in other organs, no specific therapeutic intervention was administered. After the discontinuation of immunotherapy, the sarcoidosis-like reaction regressed without cancer relapse.

Conclusions

Clinicians should be aware of the possibility of DISR as an irAE during the ICI treatment of mCRC. In suspected cases of DISR following ICI therapy, it is important to differentiate between cancer progression and DISR through histological diagnosis for the subsequent strategy, as radiological and serological findings are not definitive.

The Prognostic and therapeutic value and clinical implications of fibroblast activation protein-α as a novel biomarker in colorectal cancer

The identification of contributing factors leading to the development of Colorectal Cancer (CRC), as the third fatal malignancy, is crucial. Today, the tumor microenvironment has been shown to play a key role in CRC progression. Fibroblast-Activation Protein-α (FAP) is a type II transmembrane cell surface proteinase expressed on the surface of cancer-associated fibroblasts in tumor stroma. As an enzyme, FAP has di- and endoprolylpeptidase, endoprotease, and gelatinase/collagenase activities in the Tumor Microenvironment (TME). According to recent reports, FAP overexpression in CRC contributes to adverse clinical outcomes such as increased lymph node metastasis, tumor recurrence, and angiogenesis, as well as decreased overall survival. In this review, studies about the expression level of FAP and its associations with CRC patients' prognosis are reviewed. High expression levels of FAP and its association with clinicopathological factors have made as a potential target. In many studies, FAP has been evaluated as a therapeutic target and diagnostic factor into which the current review tries to provide a comprehensive insight. Video Abstract.

B7H4 Expression Is More Frequent in MSS Status Colorectal Cancer and Is Negatively Associated with Tumour Infiltrating Lymphocytes

The immunotherapies based on ICIs in CRC are nowadays limited to microsatellite unstable tumours which are approximately 15% of all CRC cases. There are a few new immune checkpoints belonging to the B7 family, including B7H4. B7H4 expression is associated with so-called “cold tumours”, and its function is linked to the downregulation of various immune cell populations. Our study aimed to investigate whether B7H4 expression is dependent on microsatellite status in CRC and on elucidating the immunological context in which the expression of B7H4 occurs. We enrolled 167 patients in the study. We prepared the homogenates from tumour tissues and healthy adjacent tissue to assess the B7H4 levels and the Bio-Plex Pro Human 48-cytokine panel. We assessed the microsatellite status of the tumour, B7H4 expression, CD8+ T cell population, and the TILs and budding in H + E stained slides by the IHC method. We used an online available database for further exploring the biological characteristics of B7H4. The expression of B7H4 was more frequent in microsatellite stable tumours, and was negatively associated with TILs. B7H4 is positively correlated with antitumour immunosuppressive iTME, thus contributing to the immunosuppressive environment in CRC.

Current Landscape and Potential Challenges of Immune Checkpoint Inhibitors in Microsatellite Stable Metastatic Colorectal Carcinoma

Colorectal cancer (CRC) is the third most frequent cancer and the second most common cause of cancer-related death in Europe. High microsatellite instability (MSI-H) due to a deficient DNA mismatch repair (dMMR) system can be found in 5% of metastatic CRC (mCRC) and has been established as a biomarker of response to immunotherapy in these tumors. Therefore, immune checkpoint inhibitors (ICIs) in mCRC with these characteristics were evaluated with results showing remarkable response rates and durations of response. The majority of mCRC cases have high levels of DNA mismatch repair proteins (pMMR) with consequent microsatellite stability or low instability (MSS or MSI-low), associated with an inherent resistance to ICIs. This review aims to provide a comprehensive analysis of the possible approaches to overcome the mechanisms of resistance and evaluates potential biomarkers to establish the role of ICIs in pMMR/MSS/MSI-L (MSS) mCRC.

Survival for patients with metastatic colon cancer underwent cytoreductive colectomy in the era of rapid development of anticancer drugs: A real-world analysis based on updated population dataset of 2004-2018

Objective: Metastatic colon cancer (mCC) poses a great threat to the survival of patients suffering from it. In the past decade, many clinical trials have been carried out to improve the prognosis of patients with mCC. Numerous treatments have emerged, and satisfactory efficacy has been demonstrated in randomized phase III trials in highly selective patients with mCC. Our present study aims to investigate whether these therapeutic advances can be reflected to the broader mCC patients who performed cytoreductive colectomy. Method: General and prognostic data for patients diagnosed with mCC who underwent cytoreductive colectomy between 2004-2018 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Survival was analyzed using the Kaplan-Meier method and Cox proportional hazards model. The hazard ratio (HR) and its 95% confidence interval (CI) were used to evaluate the influence of risk factors on prognosis. Results: A total of 26,301 patients diagnosed with mCC treated with cytoreductive colectomy were included in this study. The median overall survival was 19 months (range, 17-23). The good prognosis was associated with patients diagnosed at the most recent year, younger age, non-black race, female, married, without previous history of malignancy, no second malignancy onset, descending/sigmoid/splenic flexure colon tumor, normal CEA levels at diagnosis, low primary tumor burden, T1/T2 stage, N0 stage, single organ metastasis, underwent surgical resection of synchronous distant metastatic lymph nodes or organs, a high number of lymph-node examinations, low positive lymph-node ratio and received adjuvant chemotherapy. The proportion of patients surviving for ≥24 months increased from 37% in 2004 to 44.2% in 2016 (p < 0.001), especially in ≤49 years patients [46.8% in 2004 to 57.8% in 2016 (p < 0.001)]. The percentage of patients who died within 3 months decreased between 2004 and 2018 (from 19.6% to 15.7%; p < 0.001). Conclusion: Over a span of 15 years, the long-term survival has improved in real-world mCC patients who were treated with cytoreductive colectomy, especially among younger patients. However, the median overall survival remains not substantial.

Real-World Activity and Safety of Trifluridine-Tipiracil Plus Bevacizumab Therapy in Patients with Refractory Metastatic Colorectal Cancer

BACKGROUND

The combination of trifluridine-tipiracil and bevacizumab was compared with trifluridine-tipiracil monotherapy in a randomized, open-label, phase II trial, resulting in a statistically significant and clinically relevant improvement in progression-free survival (PFS), with tolerable toxicity in patients with refractory metastatic colorectal cancer (mCRC); however, evidence supporting the role of this combination in a real-world setting is limited.

OBJECTIVE

The aim of our work was to provide further evidence on the activity and safety of this combination in a real-world series of Western mCRC patients refractory or intolerant to previous therapies.

PATIENT AND METHODS

We conducted a retrospective, observational study of patients with mCRC refractory or intolerant to standard therapies. Patients were treated with trifluridine-tipiracil and bevacizumab. Previous therapy with fluoropyrimidines, irinotecan, oxaliplatin, bevacizumab, aflibercept, regorafenib, and cetuximab or panitumumab (only RAS wild-type) was allowed, as was previous participation in clinical trials. Clinicopathological characteristics, overall response rate (ORR), disease control rate (DCR), overall survival (OS), PFS, and safety data were retrospectively collected and analyzed.

RESULTS

We recorded 31 patients treated between 1 December 2017 and 30 June 2022. Median age was 69 years (range 38-82 years), 39% were male, 100% had an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-1, tumor location was left-sided in 77% of cases, 54% had synchronous presentation, 35% were RAS mutant, 3% were BRAF mutant, and 71% underwent primary tumor resection; 64% of patients had liver metastases, 55% had lung metastases, and 23% had peritoneal carcinomatosis. The median number of previous treatment lines was 2 (range 0-5), and 84% of patients received at least one previous anti-angiogenic agent. The ORR and DCR were 3% and 71%, respectively. With a median follow-up of 8 months (range 2-39), median PFS was 6 months (95% confidence interval [CI] 3.1-8.9 months) and median OS was 14 months (95% CI 10.1-17.8 months). Adverse events of any grade were reported in 58% of patients. The most common grade 3-4 toxicities were neutropenia (19%) and anemia (6%); 35% of patients required either dose delays or dose reductions due to toxicity. Granulocyte colony-stimulating factor (G-CSF) prophylaxis was administered either on first or subsequent cycles of treatment in 35% of patients. No treatment-related deaths occurred. Sixty percent of the patients who discontinued treatment eventually received one or more lines of subsequent therapy.

CONCLUSIONS

Our series provides further evidence on the activity and safety of the combination of trifluridine-tipiracil and bevacizumab in a real-world series of Western refractory mCRC patients.

Deciphering colorectal cancer immune microenvironment transcriptional landscape on single cell resolution - A role for immunotherapy

Single cell RNA sequencing (scRNA-seq) is a novel high-throughput technique that enables the investigation of a single cell's entire transcriptome. It elucidates intricate cellular networks and generates indices that will eventually enable the development of more targeted and personalized medications. The importance of scRNA-seq has been highlighted in complex biological systems such as cancer and the immune system, which exhibit significant cellular heterogeneity. Colorectal cancer (CRC) is the third most common type of cancer and the second leading cause of cancer-related death globally. Chemotherapy continues to be used to treat these patients. However, 5-FU has been utilized in chemotherapy regimens with oxaliplatin and irinotecan since the 1960s and is still used today. Additionally, chemotherapy-resistant metastatic CRCs with poor prognoses have been treated with immunotherapy employing monoclonal antibodies, immune checkpoint inhibitors, adoptive cell therapy and cancer vaccines. Personalized immunotherapy employing tumor-specific neoantigens allows for treating each patient as a distinct group. Sequencing and multi-omics approaches have helped us identify patients more precisely in the last decade. The introduction of modern methods and neoantigen-based immunotherapy may usher in a new era in treating CRC. The unmet goal is to better understand the cellular and molecular mechanisms that contribute to CRC pathogenesis and resistance to treatment, identify novel therapeutic targets, and make more stratified and informed treatment decisions using single cell approaches. This review summarizes current scRNA-seq utilization in CRC research, examining its potential utility in the development of precision immunotherapy for CRC.

Dostarlimab: A Review

Dostarlimab (JEMPERLI) is a PD-1 monoclonal antibody for the treatment of adult patients, with mismatch repair deficient (dMMR), recurrent or advanced endometrial cancer that has progressed on or following prior therapy with a platinum-containing regimen. As determined by an FDA-approved test this indication was granted rapid approval based on the rate of tumor response and the duration of the response. Continued approval for this indication is conditioned on further confirmatory trials demonstrating and documenting clinical benefit. In June 2022, the clinical trial NCT04165772 reported a 100% remission rate for rectal cancer. This clinical trial brought proof that we can match a tumor and the genetics of what is driving it, with therapy. This clinical trial continues to enroll patient and is currently enrolling patients with gastric, prostate, and pancreatic cancers. Dostarlamib is being recommended for rectal cancer. The focus of this review is to summarize the existing knowledge regarding Dostarlimab and explore the possibilities of mono- and combination therapies.

Clinical management of metastatic colorectal cancer in the era of precision medicine

Colorectal cancer (CRC) represents approximately 10% of all cancers and is the second most common cause of cancer deaths. Initial clinical presentation as metastatic CRC (mCRC) occurs in approximately 20% of patients. Moreover, up to 50% of patients with localized disease eventually develop metastases. Appropriate clinical management of these patients is still a challenging medical issue. Major efforts have been made to unveil the molecular landscape of mCRC. This has resulted in the identification of several druggable tumor molecular targets with the aim of developing personalized treatments for each patient. This review summarizes the improvements in the clinical management of patients with mCRC in the emerging era of precision medicine. In fact, molecular stratification, on which the current treatment algorithm for mCRC is based, although it does not completely represent the complexity of this disease, has been the first significant step toward clinically informative genetic profiling for implementing more effective therapeutic approaches. This has resulted in a clinically relevant increase in mCRC disease control and patient survival. The next steps in the clinical management of mCRC will be to integrate the comprehensive knowledge of tumor gene alterations, of tumor and microenvironment gene and protein expression profiling, of host immune competence as well as the application of the resulting dynamic changes to a precision medicine-based continuum of care for each patient. This approach could result in the identification of individual prognostic and predictive parameters, which could help the clinician in choosing the most appropriate therapeutic program(s) throughout the entire disease journey for each patient with mCRC. CA Cancer J Clin. 2022;72:000-000.

DNA Damage Repair in Brain Tumor Immunotherapy

With the gradual understanding of tumor development, many tumor therapies have been invented and applied in clinical work, and immunotherapy has been widely concerned as an emerging hot topic in the last decade. It is worth noting that immunotherapy is nowadays applied under too harsh conditions, and many tumors are defined as “cold tumors” that are not sensitive to immunotherapy, and brain tumors are typical of them. However, there is much evidence that suggests a link between DNA damage repair mechanisms and immunotherapy. This may be a breakthrough for the application of immunotherapy in brain tumors. Therefore, in this review, first, we will describe the common pathways of DNA damage repair. Second, we will focus on immunotherapy and analyze the mechanisms of DNA damage repair involved in the immune process. Third, we will review biomarkers that have been or may be used to evaluate immunotherapy for brain tumors, such as TAMs, RPA, and other molecules that may provide a precursor assessment for the rational implementation of immunotherapy for brain tumors. Finally, we will discuss the rational combination of immunotherapy with other therapeutic approaches that have an impact on the DNA damage repair process in order to open new pathways for the application of immunotherapy in brain tumors, to maximize the effect of immunotherapy on DNA damage repair mechanisms, and to provide ideas and guidance for immunotherapy in brain tumors.