Immunotherapy in MSI/dMMR tumors in the perioperative setting: The IMHOTEP trial

Immunotherapy in the neoadjuvant treatment of gastrointestinal tumors: is the time ripe?

Immune checkpoint inhibitors (ICIs) revolutionized the management of mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) gastrointestinal (GI) cancers. Based on notable results observed in the metastatic setting, several clinical trials investigated ICIs as neoadjuvant treatment (NAT) for localized dMMR/MSI-H GI cancers, achieving striking results in terms of clinical and pathological responses and creating the opportunity to spare patients from neoadjuvant chemotherapy and/or radiotherapy and even surgical resection. Nevertheless, these impressive findings are mainly derived from small proof of concept phase II studies and there are still several open questions to address. Moreover, dMMR/MSI-H represents a limited subgroup accounting for less than 10% of GI cancers. Consequently, many efforts have been produced to investigate neoadjuvant ICIs also in mismatch repair-proficient/microsatellite stable (MSS) cancers, considering the potential synergistic effect in combining immune-targeted agents with standard therapies such as chemo and/or radiotherapy. However, results for combining ICIs to the standard of care in the unselected population are still unsatisfactory, without improvements in event-free survival in esophago-gastric adenocarcinoma for the addition of pembrolizumab to chemotherapy, and sometimes limited benefit in patients with locally advanced rectal cancer. Therefore, a major challenge will be to identify among the heterogenous spectrum of this disease, those patients that could take advantage of neoadjuvant immunotherapy and deliver the most effective treatment. In this review we discuss the rationale of NAT in GI malignancies, summarize the available evidence regarding the completed trials that evaluated this treatment strategy in both MSI-H and MSS tumors. Finally, we discuss ongoing studies and future perspectives to render neoadjuvant immunotherapy another arrow in the quiver for the treatment of locally advanced GI tumors.

Non-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR)

INTRODUCTION

This article is a summary of the French intergroup guidelines regarding the management of non-metastatic colon cancer (CC), revised in November 2022.

METHODS

These guidelines represent collaborative work of all French medical and surgical societies involved in the management of CC. Recommendations were graded in three categories (A, B, and C) according to the level of evidence found in the literature published up to November 2022.

RESULTS

Initial evaluation of CC is based on clinical examination, colonoscopy, chest-abdomen-pelvis computed tomography (CT) scan, and carcinoembryonic antigen (CEA) assay. CC is usually managed by surgery and adjuvant treatment depending on the pathological findings. The use of adjuvant therapy remains a challenging question in stage II disease. For high-risk stage II CC, adjuvant chemotherapy must be discussed and fluoropyrimidine monotherapy or oxaliplatin-based chemotherapy proposed according to the type and number of poor prognostic features. Oxaliplatin-based chemotherapy (FOLFOX or CAPOX) is the current standard for adjuvant therapy of patients with stage III CC. However, these regimens are associated with significant oxaliplatin-induced neurotoxicity. The results of the recent IDEA study provide evidence that 3 months of treatment with CAPOX is as effective as 6 months of oxaliplatin-based therapy in patients with low-risk stage III CC (T1-3 and N1). A 6-month oxaliplatin-based therapy remains the standard of care for high-risk stage III CC (T4 and/or N2). For patients unfit for oxaliplatin, fluoropyrimidine monotherapy is recommended.

CONCLUSION

French guidelines for non-metastatic CC management help to offer the best personalized therapeutic strategy in daily clinical practice. Each individual case must be discussed within a multidisciplinary tumor board and then the treatment option decided with the patient.

Chronic gastrointestinal immune-related adverse events in patients exposed to immune checkpoint inhibitors

BACKGROUND AND AIMS

Immune checkpoint inhibitors (ICI) cause acute gastrointestinal (GI) immune-related adverse events (IrAEs). We aimed to report and describe chronic GI IrAEs.

METHODS

We included consecutive patients addressed to a single center between October 2010 and March 2022 for endoscopic and/or histological GI inflammation persisting at least six months after the last dose of ICI.

RESULTS

Among a total of 178 patients addressed for GI IrAE, 14 met the inclusion criteria (8 %). The median follow-up was 13 months after discontinuation of ICI. The most common symptom was watery diarrhea (54 %). Ten (77 %) patients had colonic involvement and three patients (21 %) had ileal involvement. Ten patients (77 %) had inflammatory lesions, two patients (15 %) had fistulas and one patient had (8 %) a stricture. All patients had lymphoplasmacytic infiltrate and basal plasmacytosis, and seven (54 %) had crypt distortions. Nine patients (69 %) received medical therapy, including five patients treated with vedolizumab, two patients (15 %) underwent intestinal resection. At the last follow-up, seven of the 13 patients were receiving maintenance therapy. Endoscopic lesions persisted one year after discontinuing ICI in 4/6 patients, and two years after discontinuation in 3/4 patients.

CONCLUSIONS

Chronic GI IrAEs exist after ICI use.

The Evolving Landscape of Neoadjuvant Immunotherapy in Gastroesophageal Cancer

Despite advances in treatment strategies and surgical approaches in recent years, improving survival outcomes in esophagogastric cancer (EGC) patients treated with curative intent remains a significant area of unmet need. The recent emergence of adjuvant immunotherapy as the standard of care for resected EGC demonstrates the impact of immunotherapy in improving recurrence-free survival. Neoadjuvant and perioperative immunotherapies represent another promising approach with potential advantages over adjuvant therapy. Despite the promising results of early neoadjuvant immunotherapy studies, there are several challenges and future research needs. The optimal timing, duration and number of doses in relation to surgery and the optimal combination of immunotherapies are still unclear. In addition, rigorous correlative studies need to be performed to identify biomarkers for patient selection and treatment response prediction to maximize the benefits of neoadjuvant immunotherapy. In this review, we provide a concise summary of the current standard of care for resectable EGC and discuss the rationale for the use of immune checkpoint inhibitors in this setting and the pre-clinical and early clinical data of these novel therapies. Finally, we will examine the potential role and future direction of immunotherapy in the treatment paradigm and the perceived challenges and opportunities that lay ahead.

Neoadjuvant Immune Checkpoint Inhibitor Therapy for Localized Deficient Mismatch Repair Colorectal Cancer: A Review

Importance

Colorectal cancers (CRCs) with deficient DNA mismatch repair (dMMR) account for 15% of all CRCs. Deficient MMR is a predictive biomarker associated with responsiveness to immune checkpoint inhibitors (ICIs) in solid tumors, including CRC. The remarkable effectiveness of ICIs in metastatic CRC has led to their evaluation in the neoadjuvant and adjuvant treatment of localized disease.

Observations

Multiple prospective phase 2 studies in limited numbers of patients with localized dMMR CRC demonstrate high complete clinical and pathological response rates (60%-100%) to neoadjuvant ICIs, with low rates of grade 3 or higher ICI-related toxic effects. Given the median follow-up of 12 to 25 months in these studies, longer-term monitoring is needed to determine the durability of response and to ensure that oncologic outcomes are not compromised in patients undergoing nonoperative management. Neoadjuvant ICI therapy is especially attractive for patients with rectal cancer given the significant morbidity that accompanies pelvic irradiation and total mesorectal excision. Ongoing and planned prospective phase 2 trials will provide further data on important issues, including optimal neoadjuvant treatment duration, ICI monotherapy vs combination, and the need for adjuvant ICI therapy.

Conclusions and Relevance

While this review found that early results of neoadjuvant immunotherapy for localized dMMR CRC show high rates of major and complete pathological response, longer-term follow-up data are needed to ensure that oncologic outcomes are not compromised and are ideally improved. Neoadjuvant ICI therapy in localized dMMR CRC represents a potential paradigm shift with implications for organ preservation.

Treatment of gastric adenocarcinoma: A rapidly evolving landscape

Gastric adenocarcinoma (GC) and gastroesophageal junction adenocarcinoma represent frequent and severe diseases whose management has radically changed over the last 10 years. With the advent of second- and third-line standard therapies for metastatic GC patients in the 2010s, the molecular dismemberment of the disease and positive trials with immunotherapy and targeted agents will mark the 2020s. New treatment options have emerged in the neoadjuvant, adjuvant, and metastatic setting. In addition to improved multimodal treatment in operable patients, new subgroups have emerged depending on molecular alterations (HER2, Microsatellite instability) or expression of specific proteins in the tumour (PDL1, Claudin 18.2) making immunohistochemistry central in profiling the tumour for an optimal individualised management. The aim of this review is to describe the current standards of management of early and late stage GC and the molecular markers needed today to optimally manage our patients together with future perspectives on this disease.

[Novel Treatment Concepts in Patients with Colorectal Carcinomas and High Microsatellite Instability]

Approximately 15% of patients with colorectal cancer show high microsatellite instability (MSI-high) in their tumour tissue. For one third of these patients, there is a hereditary cause for this finding - that leads to the diagnosis of Lynch Syndrome. In combination with clinical findings such as the Amsterdam or the revised Bethesda criteria, MSI-high status has been used as a tool in identifying patients at risk. Today, MSI-status has gained much more importance, due to its impact on treatment decisions. Patients with UICC II cancers should not receive adjuvant treatment. For patients with distant metastases and MSI-high status, immune checkpoint inhibitors can be given as first line therapy - with tremendous success. Novel data show a deep response for immune checkpoint antibodies in patients with locally advanced colon as well as rectal cancer in a neoadjuvant setting. Especially for patients with MSI-high rectal cancer, there might be a novel therapeutic regimen utilising immune checkpoint inhibitors without neoadjuvant radio-chemotherapy and even without surgery. This could lead to a relevant reduction in morbidity in this patient cohort. In conclusion, universal MSI-testing is essential for identifying patients at risk for Lynch syndrome and for optimal decision making in treatment planning.

Landscapes and mechanisms of CD8+ T cell exhaustion in gastrointestinal cancer

CD8+ T cells, a cytotoxic T lymphocyte, are a key component of the tumor immune system, but they enter a hyporeactive T cell state in long-term chronic inflammation, and how to rescue this depleted state is a key direction of research. Current studies on CD8+ T cell exhaustion have found that the mechanisms responsible for their heterogeneity and differential kinetics may be closely related to transcription factors and epigenetic regulation, which may serve as biomarkers and potential immunotherapeutic targets to guide treatment. Although the importance of T cell exhaustion in tumor immunotherapy cannot be overstated, studies have pointed out that gastric cancer tissues have a better anti-tumor T cell composition compared to other cancer tissues, which may indicate that gastrointestinal cancers have more promising prospects for the development of precision-targeted immunotherapy. Therefore, the present study will focus on the mechanisms involved in the development of CD8+ T cell exhaustion, and then review the landscapes and mechanisms of T cell exhaustion in gastrointestinal cancer as well as clinical applications, which will provide a clear vision for the development of future immunotherapies.

Recent Advances in the Systemic Treatment of Localized Gastroesophageal Cancer

The overall survival expectancy of localized gastroesophageal cancer patients still remains under 5 years despite advances in neoadjuvant and adjuvant treatment strategies in recent years. For almost a decade, immunotherapy has been successfully implemented as a first-line treatment for various oncological diseases in advanced stages. In the case of advanced gastroesophageal cancer, 2021 witnessed several approvals of immune checkpoint inhibitor therapies by different authorities. Although it is still a debate whether this treatment should be restricted to a certain subgroup of patients based on biomarker selection, immunotherapy agents are making remarkable steps in resectable settings as well. The Checkmate-577 study demonstrated significant benefits of nivolumab as an adjuvant treatment for resectable esophageal and gastroesophageal junction tumors and thereby obtained approvals both from U.S. American and European authorities. First results of further potential practice-changing clinical trials are expected in 2023, which might change the treatment armamentarium for resectable gastroesophageal cancers significantly. This review aims to demonstrate the advances of immunotherapy and targeted therapies in treatment of localized gastric, gastroesophageal junction and esophageal tumors and gives a short summary on promising ongoing clinical trials.

Pattern of recurrence and overall survival in esophagogastric cancer after perioperative FLOT and clinical outcomes in MSI-H population: the PROSECCO Study

BACKGROUND

FLOT regimen is the standard perioperative treatment in Western countries for patients with locally advanced gastric (GC) or gastroesophageal junction cancer (GEJC). High microsatellite instability (MSI-H) and Mismatch Repair deficient (dMMR) demonstrated a favorable prognostic role and a concomitant negative predictive impact on the benefit of perioperative 5-fluorouracil-based doublets; however, its role in pts receiving FLOT chemotherapy is still unclear.

METHODS

This is a retrospective, multicenter observational study of 265 pts with GC/GEJC treated with perioperative FLOT regimen in 11 Italian oncology centers between January 2017 to December 2021 and analyzed for microsatellite status.

RESULTS

The MSI-H phenotype was found in 27 (10.2%) of 265 analyzed tumors. Compared to microsatellite stable (MSS) and Mismatch Repair proficient (pMMR) cases, MSI-H/dMMR were more frequently female (48.1% vs. 27.3%, p = 0.0424), elderly pts (age > 70 years, 44.4% vs. 13.4%, p = 0.0003), Laurens's intestinal type (62.5% vs. 36.1%, p = 0.02) and pts with a primary location tumor in the antrum (37 vs. 14.3%, p = 0.0004). A statistically significant difference in the rate of pathologically negative lymph node emerged (63% vs 30.7%, p = 0.0018). Compared to the MSS/pMMR tumor population, the MSI-H/dMMR subgroup had a better DFS (median not reached [NR] vs. 19.5 [15.59-23.59] mos, p = 0.031) and OS (median NR vs. 34.84 [26.68-47.60] mos, p = 0.0316).

CONCLUSIONS

These real-world data confirm that FLOT treatment is effective in daily clinical practice for locally advanced GC/GEJC, also in the MSI-H/dMMR subgroup. It also showed a higher rate of nodal status downstaging and a better outcome of MSI-H/dMMR pts in comparison to MSS/pMMR.

Updates in gynecologic care for individuals with lynch syndrome

Lynch syndrome is an autosomal dominant hereditary cancer syndrome caused by germline pathogenic variants (PVs) in DNA mismatch repair genes (MLH1, MSH2, PMS2, MSH6) or the EPCAM gene. It is estimated to affect 1 in 300 individuals and confers a lifetime risk of cancer of 10-90%, depending on the specific variant and type of cancer. Lynch syndrome is the most common cause of inherited colorectal cancer, but for women, endometrial cancer is more likely to be the sentinel cancer. There is also evidence that certain PVs causing Lynch syndrome confer an increased risk of ovarian cancer, while the risk of ovarian cancer in others is not well defined. Given this, it is essential for the practicing gynecologist and gynecologic oncologist to remain up to date on the latest techniques in identification and diagnosis of individuals with Lynch syndrome as well as evidence-based screening and risk reduction recommendations for those impacted. Furthermore, as the landscape of gynecologic cancer treatment shifts towards treatment based on molecular classification of tumors, knowledge of targeted therapies well-suited for mismatch repair deficient Lynch tumors will be crucial. The objective of this review is to highlight recent updates in the literature regarding identification and management of individuals with Lynch syndrome as it pertains to endometrial and ovarian cancers to allow gynecologic providers the opportunity to both prevent and identify Lynch-associated cancers earlier, thereby reducing the morbidity and mortality of the syndrome.

Pathological complete response after neoadjuvant immunotherapy combined with chemotherapy in pediatric rectal carcinoma: A case report

Background

Pediatric colorectal carcinoma (PCRC) is a rare non-embryonal tumor with an incidence of 0.1% to 1% of adults. Immune checkpoint inhibitors (ICIs) targeting programmed death-1 (PD-1) have shown significant efficacy in defective mismatch repair/Microsatellite instability-high (dMMR/MSI-H) metastatic CRC (mCRC). Although several studies have reported neoadjuvant immunotherapy (NIT) in MSI-H/dMMR non-mCRC patients, not all patients achieved pathological complete remission (pCR). There are differences between PCRC and adult colorectal carcinoma (CRC), and the role of NIT in PCRC remains to be further defined.

Case presentation

We report the case of a 12-year-old child who was admitted to the hospital with abdominal pain and vomiting for more than 3 months. The child's diagnosis was difficult and complex. He was initially diagnosed with intestinal obstruction, eventually diagnosed with a rare PCRC and identified as locally advanced colorectal cancer (LACRC) with genetic sequencing results showing MSI-H. After a thorough evaluation by clinicians, he received 4 cycles of Camrelizumab (anti-PD-1 antibody) + CapeOx (capecitabine and oxaliplatin) NIT combination chemotherapy. Repeat imaging and all tumor markers were unremarkable, and R0 resection was achieved. Postoperative pathology showed a tumor regression grade (TRG) of 0 grade determined as pCR. Postoperative review has not shown any recurrence or metastasis to date and the prognosis is good.

Conclusion

PCRC should improve the diagnostic efficiency to prevent misdiagnosis and miss the best time for treatment. NIT and or chemotherapy can be a reasonable and effective treatment option for dMMR/MSI-H locally advanced PCRC. Our report provides some support and evidence for neoadjuvant immunotherapy for locally advanced PCRC, while highlighting the importance of preoperative detection of microsatellite status for locally advanced PCRC.