Association of Antibiotic Exposure With Survival and Toxicity in Patients With Melanoma Receiving Immunotherapy

The impact of antibiotic use on clinical features and survival outcomes of cancer patients treated with immune checkpoint inhibitors

Background

Nowadays, immune checkpoint inhibitors (ICIs) have become one of the essential immunotherapies for cancer patients. However, the impact of antibiotic (ATB) use on cancer patients treated with ICIs remains controversial.

Methods

Our research included retrospective studies and a randomized clinical trial (RCT) with cancer patients treated with ICIs and ATB, from the public database of PubMed, Web of Science, Embase, Cochrane, clinical trials, and JAMA. The survival outcomes included progression-free survival (PFS) and overall survival (OS). Meanwhile, hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated, and subgroup analyses were performed to determine the concrete association between ATB use and the prognosis of cancer patients treated in ICIs.

Results

Our results revealed that ATB use was associated with poor survival outcomes, including OS (HR: 1.94, 95% CI: 1.68–2.25, p <0.001) and PFS (HR: 1.83, 95% CI: 1.53–2.19, p <0.001). The subgroup analysis learned about the association between ATB use and the prognosis of cancer patients with ICI treatment, including 5 cancer types, 3 kinds of ICI, 5 different ATP windows, broad-spectrum ATB class, and ECOG score. ATB treatment was associated with poor OS of non-small-cell lung cancer (NSCLC), renal cell carcinoma (RCC), esophageal cancer (EC), and melanoma (MEL) in patients treated in ICIs, while non-small-cell lung cancer (NSCLC) and renal cell carcinoma (RCC) were associated with poor PFS. Meanwhile, it was strongly related to the ICI type and ATB window. Furthermore, it is firstly mentioned that the use of broad-spectrum ATB class was strongly associated with poor PFS.

Conclusion

In conclusion, our meta-analysis indicated that ATB use was significantly associated with poor OS and PFS of cancer patients treated with ICI immunotherapy, especially for patients with ATB use in the period of (−60 days; +30 days) near the initiation of ICI treatment. Also, different cancer types and the ICI type can also impact the survival outcome. This first reveals the strong relationship between the broad-spectrum ATB class and poor PFS. Still, more studies are needed for further study.

The gut microbiome, immune check point inhibition and immune-related adverse events in non-small cell lung cancer

Systemic treatment options for patients with lung cancer have expanded in recent years, with a number of immunotherapeutic strategies now in our treatment armamentarium. Toxicity of and resistance to treatment hold a major stake in lung cancer morbidity and mortality. Herein, we summarise the background, current evidence and potential mechanisms underlying the role of the commensal gut microbiota in immunotherapy outcomes such as response and toxicity in patients with non-small cell lung cancer (NSCLC).

Mycobiota and C-Type Lectin Receptors in Cancers: Know thy Neighbors

Numerous studies have demonstrated the importance of gut bacteria in the development of malignancy, while relatively little research has been done on gut mycobiota. As a part of the gut microbiome, the percentage of gut mycobiota is negligible compared to gut bacteria. However, the effect of gut fungi on human health and disease is significant. This review systematically summarizes the research progress on mycobiota, especially gut fungi, in patients with head and neck cancer (HNC), esophageal cancer (EC), gastric cancer (GC), colorectal cancer (CRC), hepatocellular carcinoma (HCC), pancreatic cancer, melanoma, breast cancer, and lung carcinoma-induced cachexia. Moreover, we also describe, for the first time in detail, the role of the fungal recognition receptors, C-type lectin receptors (CLRs) (Dectin-1, Dectin-2, Dectin-3, and Mincle) and their downstream effector caspase recruitment domain-containing protein 9 (CARD9), in tumors to provide a reference for further research on intestinal fungi in the diagnosis and treatment of malignant tumors.

Gut Microbiota and Immunotherapy

The gut microbiota is the largest microbiota in the body, which is closely related to the immune state of the body. A number of studies have shown that gut microbiota and its metabolites are involved in host immune regulation. Immune checkpoint inhibitors have become an important drug for the treatment of many malignant tumors, which can significantly improve the prognosis of tumor patients. However, a considerable number of patients cannot benefit from immune checkpoint inhibitors. At present, the known treatment methods of microbiota manipulation mainly include fecal microbiota transplantation, dietary regulation, prebiotics and so on. Therefore, this paper will discuss the possibility of improving the anti-tumor efficacy of immunotherapy from the perspectives of the gut microbiota and immunotherapy.

The Association Between Antibiotic Use and Outcome Among Metastatic Melanoma Patients Receiving Immunotherapy

BACKGROUND

Several observational studies have reported a decreased response to immune checkpoint inhibitors (ICI) following antibiotic use. ICI activity has been hypothesized to be impaired by antibiotic-induced gut dysbiosis.

METHODS

Patients with advanced melanoma receiving an anti-PD-1 antibody as a first-line therapy between 2015 and 2017 in France were selected using the French Health Insurance database. We compared overall survival and time-to-treatment discontinuation according to antibiotic exposure in the 3 months prior to the initiation of anti-PD-1 antibody. To disentangle a causal effect of antibiotics from a confounding bias, we balanced characteristics of patients exposed and nonexposed to antibiotics using an overlap weighting method based on a propensity score. We also evaluated a control cohort of patients with advanced melanoma receiving first-line targeted therapy, as there is no rationale for decreased efficacy of targeted therapy following antibiotic treatment.

RESULTS

The anti-PD-1 antibody cohort comprised 2605 individuals. Antibiotic exposure in the 3 months prior to anti-PD-1 antibody initiation was not associated with shorter overall survival (weighted hazard ratio = 1.01, 95% confidence interval = 0.88 to 1.17) or time-to-treatment discontinuation (weighted hazard ratio = 1.00, 95% confidence interval = 0.89 to 1.11). Consistent results were observed when the time frame of antibiotics was narrowed to 1 month prior to anti-PD-1 initiation or when exposure was restricted to antibiotics leading to more profound gut dysbiosis. Similar results were observed in the targeted therapy cohort.

CONCLUSIONS

In a large cohort of advanced melanoma patients, we showed that antibiotic use preceding anti-PD-1 antibody was not associated with worse outcome. Physicians should not delay immunotherapy for patients who have recently received antibiotics.

Association of Blood Biochemical Indexes and Antibiotic Exposure With Severe Immune-related Adverse Events in Patients With Advanced Cancers Receiving PD-1 Inhibitors

Some patients with cancer treated with programmed death 1 (PD-1) inhibitors experience immune-related severe adverse events (ir-SAEs), however, predictors are limited. The objective was to identify clinicopathologic features that may be associated with a higher ir-SAE risk. This was a nested case-control study. After screening a total of 832 PD-1 inhibitor-treated patients, we identified 42 ir-SAE cases. According to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, ir-SAEs were defined as grade ≥3 toxic effects associated with immunotherapy. A total of 126 controls were matched. The crude and adjusted risks of ir-SAEs were estimated by odds ratio (ORs) and 95% CIs using multivariate logistic regression models. Baseline neutrophil-to-lymphocyte ratio (NLR) [per SD increment-adjusted (aOR): 1.16], lactate dehydrogenase (LDH) ≥245 U/L (aOR: 2.39), and antibiotic exposure (aOR: 4.39) were associated with a higher risk of ir-SAEs. When NLR was categorized in 3 groups, significantly higher risks of ir-SAEs (aOR: 4.95) were found in participants in group 3 (>6) than in those in group 1 (<3). Furthermore, NLR (per SD increment-adjusted hazard ratio:1.08) were also significantly associated with shorter overall survival (OS). Baseline LDH ≥245 U/L and antibiotic exposure were no significant association with OS. In conclusion, ir-SAEs were associated between baseline NLR, LDH ≥245 U/L and antibiotic exposure. Lower NLR was correlated with longer OS for cancer.

The cure from within? a review of the microbiome and diet in melanoma

Therapy for cutaneous melanoma, the deadliest of the skin cancers, is inextricably linked to the immune system. Once thought impossible, cures for metastatic melanoma with immune checkpoint inhibitors have been developed within the last decade and now occur regularly in the clinic. Unfortunately, half of tumors do not respond to checkpoint inhibitors and efforts to further exploit the immune system are needed. Tantalizing associations with immune health and gut microbiome composition suggest we can improve the success rate of immunotherapy. The gut contains over half of the immune cells in our bodies and increasingly, evidence is linking the immune system within our gut to melanoma development and treatment. In this review, we discuss the importance the skin and gut microbiome may play in the development of melanoma. We examine the differences in the microbial populations which inhabit the gut of those who develop melanoma and subsequently respond to immunotherapeutics. We discuss the role of dietary intake on the development and treatment of melanoma. And finally, we review the landscape of published and registered clinical trials therapeutically targeting the microbiome in melanoma through dietary supplements, fecal microbiota transplant, and microbial supplementation.

Gut microbiota-drug interactions in cancer pharmacotherapies: implications for efficacy and adverse effects

INTRODUCTION

The gut microbiota is involved in host physiology and health. Reciprocal microbiota-drug interactions are increasingly recognized as underlying some individual differences in therapy response and adverse events. Cancer pharmacotherapies are characterized by a high degree of interpatient variability in efficacy and side effect profile and recently, the microbiota has emerged as a factor that may underlie these differences.

AREAS COVERED

The effects of cancer pharmacotherapy on microbiota composition and function are reviewed with consideration of the relationship between baseline microbiota composition, microbiota modification, antibiotics exposure and cancer therapy efficacy. We assess the evidence implicating the microbiota in cancer therapy-related adverse events including impaired gut function, cognition and pain perception. Finally, potential mechanisms underlying microbiota-cancer drug interactions are described, including direct microbial metabolism, and microbial modulation of liver metabolism and immune function. This review focused on preclinical and clinical studies conducted in the last 5 years.

EXPERT OPINION

Preclinical and clinical research supports a role for baseline microbiota in cancer therapy efficacy, with emerging evidence that the microbiota modification may assist in side effect management. Future efforts should focus on exploiting this knowledge towards the development of microbiota-targeted therapies. Finally, a focus on specific drug-microbiota-cancer interactions is warranted.

Intestinal Microbiome Associated With Immune-Related Adverse Events for Patients Treated With Anti-PD-1 Inhibitors, a Real-World Study

Aim

Immune checkpoint inhibitors (ICIs) have updated the treatment landscape for patients with advanced malignancies, while their clinical prospect was hindered by severe immune-related adverse events (irAEs). The aim of this study was to research the association between gut microbiome diversity and the occurrence of ICI-induced irAEs.

Patients and Method

We prospectively obtained the baseline fecal samples and clinical data from patients treated with anti-PD-1 inhibitors as monotherapy or in combination with chemotherapy or antiangiogenesis regardless of treatment lines. The 16S rRNA V3-V4 sequencing was used to test the gene amplicons of fecal samples. The development of irAEs was evaluated and monitored from the beginning of therapy based on CTCAE V5.01.

Results

A total of 150 patients were included in the study and followed up for at least 6 months. A total of 90 (60%) patients developed at least one type of adverse effect, among which mild irAEs (grades 1–2) occurred in 65 patients (72.22%) and severe irAEs (grades 3–5) in 25 patients (27.78%). Patients with severe irAEs showed a visible higher abundance of Streptococcus, Paecalibacterium, and Stenotrophomonas, and patients with mild irAEs had a higher abundance of Faecalibacterium and unidentified_Lachnospiraceae. With the aid of a classification model constructed with 5 microbial biomarkers, patients without irAEs were successfully distinguished from those with severe irAEs (AUC value was 0.66).

Conclusion

Certain intestinal bacteria can effectively distinguish patients without irAEs from patients with severe irAEs and provide evidence of gut microbiota as an informative source for developing predictive biomarkers to predict the occurrence of irAEs.

Association of antibiotic treatment with immune-related adverse events in patients with cancer receiving immunotherapy

Background

To determine whether antibiotic treatment is a risk factor for immune-related adverse events (irAEs) across different patients with cancer receiving anti-PD-1/PD-L1 therapies.

Methods

The retrospective analysis includes clinical information from 767 patients with cancer treated at Hunan Cancer Hospital from 2017 to 2020. The pharmacovigilance data analysis includes individual cases of 38,705 safety reports from the US Food and Drug Administration Adverse Event Reporting System (FAERS) from 2014 to 2020, and 25,122 cases of safety reports from the World Health Organization database VigiBase from 2014 to 2019. All cases that received anti-PD-1/PD-L1 treatment were included. Multiomics data from patients across 25 cancer types were download from The Cancer Genome Atlas. Logistic regression and propensity score algorithm was employed to calculate OR of irAEs.

Results

Retrospective analysis of in-house patients showed that irAE potential risks are higher in all cancer (OR 2.12, 95% CI 1.38 to 3.22, false discovery rate (FDR) adjusted-p=1.93×10⁻³) and patients with lung cancer (OR 3.16, 95% CI 1.67 to 5.95, FDR adjusted-p=1.93×10⁻³) when using antibiotics. Potential risk of irAEs in patients with lung cancer with antibiotic treatment is significantly higher in FAERS (OR 1.39, 95% CI 1.21 to 1.59; FDR adjusted-p=1.62×10⁻⁵) and VigiBase (OR 1.32, 95% CI 1.09 to 1.59, FDR adjusted-p=0.05). Mechanistically, decreased microbial diversity caused by antibiotics use may increase the irAE risk through mediating the irAE-related factors.

Conclusions

Our study is the first to comprehensively demonstrate the associations of irAEs and antibiotic during anti-PD-1/PD-L1 therapy across a wide spectrum of cancers by analyzing multisource data. Administration of antibiotics should be carefully evaluated in patients with cancer treated by anti-PD-1/PD-L1 to avoid potentially increasing irAE risk.

Recent advances in primary resistance mechanisms against immune checkpoint inhibitors

PURPOSE OF REVIEW

The resistance of immune checkpoint inhibitors (ICIs) has become an obstacle to further improve the survival of patients with advanced cancer. This review provides an overview of recent advances in primary resistance mechanisms of ICIs.

RECENT FINDINGS

With the improvement of study approach, new characteristics and trends have emerged in the classification of tumor immune subtypes. The effects of germline genetic on tumor microenvironment and the efficacy of immunotherapy have been further studied. Exosomal programmed death-ligand 1 (PD-L1) is an increasing focus of research in primary resistance mechanisms of ICIs. In addition to antibiotics and steroids, the influence of other concomitant medications on the efficacy of ICIs has recently gained more attention.

SUMMARY

Exploring the resistance mechanisms of ICIs is one of the great challenges in the field of tumor immunotherapy. Continued work to understand the resistance mechanism of ICIs is ongoing.

Risk Factors for Infections, Antibiotic Therapy, and Its Impact on Cancer Therapy Outcomes for Patients with Solid Tumors

Infections represent a significant cause of morbidity and mortality in cancer patients. Multiple factors related to the patient, tumor, and cancer therapy can affect the risk of infection in patients with solid tumors. A thorough understanding of such factors can aid in the identification of patients with substantial risk of infection, allowing medical practitioners to tailor therapy and apply prophylactic measures to avoid serious complications. The use of novel treatment modalities, including targeted therapy and immunotherapy, brings diagnostic and therapeutic challenges into the management of infections in cancer patients. A growing body of evidence suggests that antibiotic therapy can modulate both toxicity and antitumor response induced by chemotherapy, radiotherapy, and especially immunotherapy. This article provides a comprehensive review of potential risk factors for infections and therapeutic approaches for the most prevalent infections in patients with solid tumors, and discusses the potential effect of antibiotic therapy on toxicity and efficacy of cancer therapy.

A new biological triangle in cancer: intestinal microbiota, immune checkpoint inhibitors and antibiotics

Cancer immunotherapy has revolutionized the treatment of many malignant tumors. Although immune checkpoint inhibitors (ICIs) can reactivate the anti-tumor activity of immune cells, sensitivity to immune checkpoint inhibitor therapy depends on the complex tumor immune processes. In recent years, numerous researches have demonstrated the role of intestinal microbiota in immunity and metabolism of the tumor microenvironment, as well as the efficacy of immunotherapy. Epidemiological studies have further demonstrated the efficacy of antibiotic therapy on the probability of patients' response to ICIs and predictability of the short-term survival of cancer patients. Disturbance to the intestinal microbiota significantly affects ICIs-mediated immune reconstitution and is considered a possible mechanism underlying the development of adverse effects during antibiotic-based ICIs treatment. Intestinal microbiota, antibiotics, and ICIs have gradually become important considerations for the titer of immunotherapy. In the case of immunotherapy, the rational use of antibiotics and intestinal microbiota is expected to yield a better prognosis for patients with malignant tumors.

Immune checkpoint inhibitors in melanoma

Immune checkpoint inhibitors target the dysfunctional immune system, to induce cancer-cell killing by CD8-positive T cells. Immune checkpoint inhibitors, specifically anti-CTLA4 and anti-PD-1 antibodies, have revolutionised the management of many cancers, particularly advanced melanoma, for which tumour regression and long-term durable cancer control is possible in nearly 50% of patients, compared with less than 10% historically. Despite the absence of adequately powered trial data, combined anti-CTLA4 and anti-PD-1 checkpoint inhibition has the highest 5-year overall survival rate of all therapies in advanced melanoma, and has high activity in melanoma brain metastases. A phase 3 study has shown the addition of an anti-LAG3 antibody to nivolumab improves progression-free survival, but its effect on overall survival and how this combination compares to combined anti-CTLA4 and anti-PD-1 checkpoint inhibition is unknown. At present, there are no highly sensitive and specific biomarkers of response to immune checkpoint inhibitors, and clinical factors, such as volume and sites of disease, serum lactate dehydrogenase, and BRAF mutation status, are used to select initial therapy for patients with advanced melanoma. Immune checkpoint inhibitors can induce autoimmune toxicities by virtue of their mechanism of action. These toxicities, termed immune-related adverse events, occur most frequently with combined anti-CTLA4 and anti-PD-1 checkpoint inhibition; can have a variety of presentations; can affect any organ system (most often the skin, colon, endocrine system, and liver); and appear to mimic classic autoimmune diseases. Immune-related adverse events require prompt recognition and management, which may be different from the autoimmune disease it mimics. Immune checkpoint inhibitors appear to be safe for use in patients with HIV, viral hepatitis, and patients with mild-to-moderate pre-existing autoimmune diseases. Patients with organ transplants can respond to immune checkpoint inhibitors but have a high chance of transplant loss. PD-1 inhibitors are now an established standard of care as adjuvant therapy in high-risk resected stage III or IV melanoma. Neoadjuvant checkpoint inhibition for resectable stage III melanoma, which is currently limited to clinical trials, is emerging as a highly effective therapy.

Intestinal microbiota influences clinical outcome and side effects of early breast cancer treatment

The prognosis of early breast cancer (BC) relies on cell autonomous and immune parameters. The impact of the intestinal microbiome on clinical outcome has not yet been evaluated. Shotgun metagenomics was used to determine the composition of the fecal microbiota in 121 specimens from 76 early BC patients, 45 of whom were paired before and after chemotherapy. These patients were enrolled in the CANTO prospective study designed to record the side effects associated with the clinical management of BC. We analyzed associations between baseline or post-chemotherapy fecal microbiota and plasma metabolomics with BC prognosis, as well as with therapy-induced side effects. We examined the clinical relevance of these findings in immunocompetent mice colonized with BC patient microbiota that were subsequently challenged with histo-compatible mouse BC and chemotherapy. We conclude that specific gut commensals that are overabundant in BC patients compared with healthy individuals negatively impact BC prognosis, are modulated by chemotherapy, and may influence weight gain and neurological side effects of BC therapies. These findings obtained in adjuvant and neoadjuvant settings warrant prospective validation.

Broad-Spectrum Antibiotic Use and Disease Progression in Early-Stage Melanoma Patients: A Retrospective Cohort Study

Animal studies and a few clinical studies have reported mixed findings on the association between antibiotics and cancer incidence. Antibiotics may inhibit tumor cell growth, but could also alter the gut-microbiome-modulated immune system and increase the risk of cancer. Studies that assess how antibiotics affect the progression of cancer are limited. We evaluated the association between broad-spectrum antibiotic use and melanoma progression. We conducted a retrospective cohort study using IQVIA PharMetrics® Plus data (2008-2018). We identified patients with malignant melanoma who underwent wide local excision or Mohs micrographic surgery within 90 days of first diagnosis. Surgery date was the index date. Patients were excluded if they had any other cancer diagnosis or autoimmune disorders in 1 year before the index date ("baseline"). Exposure to broad-spectrum antibiotics was identified in three time windows using three cohorts: 3 months prior to the index date, 1 month after the index date, and 3 months after the index date. The covariates were patients' demographic and clinical characteristics identified in the 1-year baseline period. The patients were followed from the index date until cancer progression, loss of enrollment, or the end of 2 years after the index date. Progression was defined as: (i) any hospice care after surgery, (ii) a new round of treatment for melanoma (surgery, chemotherapy, immunotherapy, targeted therapy, or radiotherapy) 180 days after prior treatment, or (iii) a metastasis diagnosis or a diagnosis of a new nonmelanoma primary cancer at least 180 days after first melanoma diagnosis or prior treatment. A high-dimensional propensity score approach with inverse weighting was used to adjust for the patients' baseline differences. Cox proportional hazard regression was used for estimating the association. The final samples included 3930, 3831, and 3587 patients (mean age: 56 years). Exposure to antibiotics was 16% in the prior-3-months, 22% in the post-1-month, and 22% in the post-3-months. In the pre-3-months analysis, 9% of the exposed group and 9% of the unexposed group had progressed. Antibiotic use was not associated with melanoma progression (HR: 0.81; 95% CI: 0.57-1.14). However, antibiotic use in subsequent 1 month and subsequent 3 months was associated with 31% reduction (HR: 0.69; 95% CI: 0.51-0.92) and 32% reduction (HR: 0.68; 95% CI: 0.51-0.91) in progression, respectively. In this cohort of patients with likely early-stage melanoma cancer, antibiotic use in 1 month and 3 months after melanoma surgery was associated with a lower risk of melanoma progression. Future studies are warranted to validate the findings.

Tumour neoantigen mimicry by microbial species in cancer immunotherapy

Tumour neoantigens arising from cancer-specific mutations generate a molecular fingerprint that has a definite specificity for cancer. Although this fingerprint perfectly discriminates cancer from healthy somatic and germline cells, and is therefore therapeutically exploitable using immune checkpoint blockade, gut and extra-gut microbial species can independently produce epitopes that resemble tumour neoantigens as part of their natural gene expression programmes. Such tumour molecular mimicry is likely not only to influence the quality and strength of the body's anti-cancer immune response, but could also explain why certain patients show favourable long-term responses to immune checkpoint blockade while others do not benefit at all from this treatment. This article outlines the requirement for tumour neoantigens in successful cancer immunotherapy and draws attention to the emerging role of microbiome-mediated tumour neoantigen mimicry in determining checkpoint immunotherapy outcome, with far-reaching implications for the future of cancer immunotherapy.

Enhancing Checkpoint Inhibitor Therapy in Solid Tissue Cancers: The Role of Diet, the Microbiome & Microbiome-Derived Metabolites

Host immunity plays a central role in the regulation of anti-tumour responses during checkpoint inhibitor therapy (CIT). The mechanisms involved in long lasting remission remain unclear. Animal studies have revealed that the microbiome influences the host immune response. This is supported by human studies linking a higher microbial richness and diversity with enhanced responses to CIT. This review focuses on the role of diet, the microbiome and the microbiome-derived metabolome in enhancing responses to current CIT in solid tissue cancers. The Western diet has been associated with dysbiosis, inflammation and numerous metabolic disorders. There is preliminary evidence that lifestyle factors including a high fibre diet are associated with improved responses to CIT via a potential effect on the microbiota. The mechanisms through which the microbiota may regulate long-term immunotherapy responses have yet to be determined, although bacterial-metabolites including short chain fatty acids (SCFAs) are recognized to have an impact on T cell differentiation, and may affect T effector/regulatory T cell balance. SCFAs were also shown to enhance the memory potential of activated CD8 T cells. Many therapeutic approaches including dietary manipulation and fecal transplantation are currently being explored in order to enhance immunotherapy responses. The microbiome-derived metabolome may be one means through which bacterial metabolic products can be monitored from the start of treatment and could be used to identify patients at risk of poor immunotherapy responses. The current review will discuss recent advances and bring together literature from related fields in nutrition, oncology and immunology to discuss possible means of modulating immunity to improve responses to current CIT.

Antimicrobial immunotherapeutics: past, present and future

In this age of antimicrobial resistance (AMR) there is an urgent need for novel antimicrobials. One area of recent interest is in developing antimicrobial effector molecules, and even cell-based therapies, based on those of the immune system. In this review, some of the more interesting approaches will be discussed, including immune checkpoint inhibitors, Interferons (IFNs), Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF), Chimeric Antigen Receptor (CAR) T cells, Antibodies, Vaccines and the potential role of trained immunity in protection from and/or treatment of infection.

Antibiotic-induced disruption of the microbiome exacerbates chemotherapy-induced diarrhoea and can be mitigated with autologous faecal microbiota transplantation

BACKGROUND

Chemotherapy is well documented to disrupt the gut microbiome, leading to poor treatment outcomes and a heightened risk of adverse toxicity. Although strong associations exist between its composition and gastrointestinal toxicity, its causal contribution remains unclear. Our inability to move beyond association has limited the development and implementation of microbial-based therapeutics in chemotherapy adjuncts with no clear rationale of how and when to deliver them.

METHODS/RESULTS

Here, we investigate the impact of augmenting the gut microbiome on gastrointestinal toxicity caused by the chemotherapeutic agent, methotrexate (MTX). Faecal microbiome transplantation (FMT) delivered after MTX had no appreciable impact on gastrointestinal toxicity. In contrast, disruption of the microbiome with antibiotics administered before chemotherapy exacerbated gastrointestinal toxicity, impairing mucosal recovery (P < 0.0001) whilst increasing diarrhoea severity (P = 0.0007) and treatment-related mortality (P = 0.0045). Importantly, these detrimental effects were reversed when the microbiome was restored using autologous FMT (P = 0.03), a phenomenon dictated by the uptake and subsequent expansion of Muribaculaceae.

CONCLUSIONS

These are the first data to show that clinically impactful symptoms of gastrointestinal toxicity are dictated by the microbiome and provide a clear rationale for how and when to target the microbiome to mitigate the acute and chronic complications caused by disruption of the gastrointestinal microenvironment. Translation of this new knowledge should focus on stabilising and strengthening the gut microbiome before chemotherapy and developing new microbial approaches to accelerate recovery of the mucosa. By controlling the depth and duration of mucosal injury, secondary consequences of gastrointestinal toxicity may be avoided.

The role of gut microbiome in modulating response to immune checkpoint inhibitor therapy in cancer

Immunotherapy has led to a paradigm shift in the treatment of several cancers. There have been significant efforts to identify biomarkers that can predict response and toxicities related to immune checkpoint inhibitor (ICPI) therapy. Despite these advances, it has been challenging to tease out why a subset of patients benefit more than others or why certain patients experience immune-related adverse events (irAEs). Although the immune-modulating properties of the human gut bacterial ecosystem are yet to be fully elucidated, there has been growing interest in evaluating the role of the gut microbiome in shaping the therapeutic response to cancer immunotherapy. Considerable research efforts are currently directed to utilizing metagenomic and metabolic profiling of stool microbiota in patients on ICPI-based therapies. Dysbiosis or loss of microbial diversity has been associated with a poor treatment response to ICPIs and worse survival outcomes in cancer patients. Emerging data have shown that certain bacterial strains, such as Faecalibacterium that confer sensitivity to ICPI, also have a higher propensity to increase the risk of irAEs. Additionally, the microbiome can modulate the local immune response at the intestinal interface and influence the trafficking of bacterial peptide primed T-cells distally, influencing the toxicity patterns to ICPI. Antibiotic or diet induced alterations in composition of the microbiome can also indirectly alter the production of certain bacterial metabolites such as deoxycholate and short chain fatty acids that can influence the anti-tumor tolerogenesis. Gaining sufficient understanding of the exact mechanisms underpinning the interplay between ICPI induced anti-tumor immunity and the immune modulatory role gut microbiome can be vital in identifying potential avenues of improving outcomes to cancer immunotherapy. In the current review, we have summarized and highlighted the key emerging data supporting the role of gut microbiome in regulating response to ICPIs in cancer.

Antibiotics and steroids, the double enemies of anticancer immunotherapy: a review of the literature

The advent of immunotherapy in onco-haematology has represented a kind of revolution that has been able to modify the prognosis of numerous tumours that until recently would have been rapidly lethal. While much is known about the mechanism of action of these drugs, relatively little is known about the factors that represent potential predictors of response and toxicity. Among these factors, the simultaneous administration of antibiotics and/or steroids seems to have a negative impact. Furthermore, several retrospective studies have highlighted the strong link between cancer and gut microbiota, regardless of the tumour site, and how microbiota, playing a key role in the prevention of systemic inflammation at various levels and in the intestinal homeostasis, can be negatively influenced by the dysbiosis caused by antibiotic therapy administered during or in the weeks immediately preceding the start of immunotherapy. Moreover, we assume that the concurrent administration of steroids, which is often necessary in cancer patients, likely results in a deleterious effect on the therapeutic outcomes of immunotherapy. In this review, we will try to clarify the evidence on the possible detrimental effects of antibiotics and steroids, which are currently considered the double enemies of anticancer immunotherapy.

The Potential Role of the Intestinal Micromilieu and Individual Microbes in the Immunobiology of Chimeric Antigen Receptor T-Cell Therapy

Cellular immunotherapy with chimeric antigen receptor (CAR)-T cells (CARTs) represents a breakthrough in the treatment of hematologic malignancies. CARTs are genetically engineered hybrid receptors that combine antigen-specificity of monoclonal antibodies with T cell function to direct patient-derived T cells to kill malignant cells expressing the target (tumor) antigen. CARTs have been introduced into clinical medicine as CD19-targeted CARTs for refractory and relapsed B cell malignancies. Despite high initial response rates, current CART therapies are limited by a long-term loss of antitumor efficacy, the occurrence of toxicities, and the lack of biomarkers for predicting therapy and toxicity outcomes. In the past decade, the gut microbiome of mammals has been extensively studied and evidence is accumulating that human health, apart from our own genome, largely depends on microbes that are living in and on the human body. The microbiome encompasses more than 1000 bacterial species who collectively encode a metagenome that guides multifaceted, bidirectional host-microbiome interactions, primarily through the action of microbial metabolites. Increasing knowledge has been accumulated on the role of the gut microbiome in T cell-driven anticancer immunotherapy. It has been shown that antibiotics, dietary components and gut microbes reciprocally affect the efficacy and toxicity of allogeneic hematopoietic cell transplantation (allo HCT) as the prototype of T cell-based immunotherapy for hematologic malignancies, and that microbiome diversity metrics can predict clinical outcomes of allo HCTs. In this review, we will provide a comprehensive overview of the principles of CD19-CART immunotherapy and major aspects of the gut microbiome and its modulators that impact antitumor T cell transfer therapies. We will outline i) the extrinsic and intrinsic variables that can contribute to the complex interaction of the gut microbiome and host in CART immunotherapy, including ii) antibiotic administration affecting loss of colonization resistance, expansion of pathobionts and disturbed mucosal and immunological homeostasis, and ii) the role of specific gut commensals and their microbial virulence factors in host immunity and inflammation. Although the role of the gut microbiome in CART immunotherapy has only been marginally explored so far, this review may open a new chapter and views on putative connections and mechanisms.

Immunomodulation by the Commensal Microbiome During Immune-Targeted Interventions: Focus on Cancer Immune Checkpoint Inhibitor Therapy and Vaccination

Emerging evidence in clinical and preclinical studies indicates that success of immunotherapies can be impacted by the state of the microbiome. Understanding the role of the microbiome during immune-targeted interventions could help us understand heterogeneity of treatment success, predict outcomes, and develop additional strategies to improve efficacy. In this review, we discuss key studies that reveal reciprocal interactions between the microbiome, the immune system, and the outcome of immune interventions. We focus on cancer immune checkpoint inhibitor treatment and vaccination as two crucial therapeutic areas with strong potential for immunomodulation by the microbiota. By juxtaposing studies across both therapeutic areas, we highlight three factors prominently involved in microbial immunomodulation: short-chain fatty acids, microbe-associate molecular patterns (MAMPs), and inflammatory cytokines. Continued interrogation of these models and pathways may reveal critical mechanistic synergies between the microbiome and the immune system, resulting in novel approaches designed to influence the efficacy of immune-targeted interventions.

Use of antibiotics is associated with worse clinical outcomes in patients with cancer treated with immune checkpoint inhibitors: A systematic review and meta-analysis

OBJECTIVES

Observational and experimental studies suggest that the use of antibiotics close to administration of immune checkpoint inhibitors (ICI) can have a negative effect on tumour response and patient survival, due to microbiome dysbiosis and the resultant suppression of host immune response against neoplastic cells.

METHODS

A systematic search of PUBMED and EMBASE was undertaken for studies published between 1 January 2017 and 1 June 2020, evaluating the association between the use of antibiotics and clinical outcomes in patients with cancer treated with ICIs. A meta-analysis of the association between the use of antibiotics and clinical outcomes was also performed.

RESULTS

Forty-eight studies met the inclusion criteria (12,794 patients). Use of antibiotics was associated with shorter overall survival [hazard ratio (HR) 1.88, 95% confidence interval (CI) 1.59-2.22; adjusted HR 1.87, 95% CI 1.55-2.25] and progression-free survival (HR 1.52, 95% CI 1.36-1.70; adjusted HR 1.93, 95% CI 1.59-2.36), decreased response rate [odds ratio (OR) 0.54, 95% CI 0.34-0.86] and more disease progression (OR 2.00, 95% CI 1.27-3.14). The negative association between the use of antibiotics and progression-free survival was stronger in patients with renal cell carcinoma or melanoma compared with lung cancer. Only antibiotic administration >1 month prior to ICI initiation was associated with increased disease progression. Heterogeneity was substantial for all outcomes.

CONCLUSIONS

Recent use of antibiotics in patients with cancer treated with ICIs was associated with worse clinical outcomes. Such patients may benefit from dedicated antimicrobial stewardship programmes.

Dermatologic infections in cancer patients treated with checkpoint inhibitors

BACKGROUND

The incidence of dermatologic infections in patients receiving checkpoint inhibitors (CPIs) has not been systematically described.

OBJECTIVE

Identify the incidence of dermatologic infections in patients who received CPIs.

METHODS

Retrospective review of dermatologic infections in patients who received CPIs between 2005 and 2020 and were evaluated by dermatologists at Memorial Sloan Kettering Cancer Center.

RESULTS

Of 2061 patients in the study, 1292 were actively receiving CPIs (≤ 90 days since the last dose) and 769 had previously been on CPIs (> 90 days since the last dose). The dermatologic infection rate was significantly higher in patients with active CPI treatment (17.5%) than in patients not actively being treated (8.2%; P < .0001). In patients on CPIs, 82 (36.2%), 78 (34.5%), and 48 (21.2%) had bacterial, fungal, and viral infections, respectively, and 18 (8.0%) had polymicrobial infections. Anti-cytotoxic T-lymphocyte-associated antigen-4 monotherapy was associated with the highest risk of infection (hazard ratio, 2.93; 95% confidence interval, 1.87 to 4.60; P < .001).

LIMITATIONS

Retrospective design and sample limited to patients referred to dermatology.

CONCLUSIONS

Patients actively receiving CPIs are more susceptible to dermatologic infections, with anti-cytotoxic T-lymphocyte-associated antigen-4 monotherapy carrying the highest risk, suggesting that the index of suspicion for infections should be increased in these patients to minimize morbidity and optimize care.

New Insights Into the Cancer-Microbiome-Immune Axis: Decrypting a Decade of Discoveries

The past decade has witnessed groundbreaking advances in the field of microbiome research. An area where immense implications of the microbiome have been demonstrated is tumor biology. The microbiome affects tumor initiation and progression through direct effects on the tumor cells and indirectly through manipulation of the immune system. It can also determine response to cancer therapies and predict disease progression and survival. Modulation of the microbiome can be harnessed to potentiate the efficacy of immunotherapies and decrease their toxicity. In this review, we comprehensively dissect recent evidence regarding the interaction of the microbiome and anti-tumor immune machinery and outline the critical questions which need to be addressed as we further explore this dynamic colloquy.

Biomarkers for precision immunotherapy in the metastatic setting: hope or reality?

Precision immunotherapy is a crucial approach to improve the efficacy of anti-cancer treatments, particularly in the metastatic setting. In this respect, accurate patient selection takes advantage of the multidimensional integration of patients' clinical information and tumour-specific biomarkers status. Among these biomarkers, programmed death-ligand 1, tumour-infiltrating lymphocytes, microsatellite instability, mismatch repair and tumour mutational burden have been widely investigated. However, novel tumour-specific biomarkers and testing methods will further improve patients' outcomes. Here, we discuss the currently available strategies for the implementation of a precision immunotherapy approach in the clinical management of metastatic solid tumours and highlight future perspectives.

Is the survival of patients treated with ipilimumab affected by antibiotics? An analysis of 1585 patients from the French National hospital discharge summary database (PMSI)

Background: The gut microbiota has a key role in the regulation of the immune system. Disruption of the gut microbiota’s composition by antibiotics might significantly affect the efficacy of immune checkpoint inhibitors. In a study of patients treated with ipilimumab, we sought to assess the relationship between overall survival and in-hospital antibiotic administration.

Methods: Patients having been treated with ipilimumab between January 2012 and November 2014 were selected from the French National Hospital Discharge Summary Database. Exposure to antibiotics was defined as the presence of a hospital stay with a documented systemic bacterial infection in the 2 months before or the month after initiation of the patient’s first ever course of ipilimumab. The primary outcome was overall survival.

Results: We studied 43,124 hospital stays involving 1585 patients from 97 centers. All patients had received ipilimumab monotherapy for advanced melanoma. Overall, 117 of the 1585 patients (7.4%) were documented as having received systemic antibiotic therapy in hospital during the defined exposure period. The median overall survival time was shorter in patients with infection (6.3 months, vs. 15.4 months in patients without an infection; hazard ratio (HR) = 1.88, 95% confidence interval [1.46; 2.43], p = 10⁻⁶). In a multivariate analysis adjusted for covariates, infection was still significantly associated with overall survival (HR = 1.68, [1.30; 2.18], p = 10⁻⁵).

Conclusions: In patients treated with ipilimumab for advanced melanoma, infection, and antibiotic administration in hospital at around the time of the patient’s first ever course of ipilimumab appears to be associated with significantly lower clinical benefit.

Antibiotics, cancer risk and oncologic treatment efficacy: a practical review of the literature

Antibiotics have been extensively used to treat infectious diseases over the past century and have largely contributed to increased life expectancy over time. However, antibiotic use can impose profound and protracted changes to the diversity of the microbial ecosystem, affecting the composition of up to 30% of the bacterial species in the gut microbiome. By modifying human microbiota composition, antibiotics alter the action of several oncologic drugs, potentially leading to decreased efficacy and increased toxicities. Whether antibiotics interfere with cancer therapies or even increase the risk of cancer development has been under investigation, and no randomised trials have been conducted so far. The aim of the current review is to describe the possible effects of antibiotic therapies on different oncologic treatments, especially immunotherapies, and to explore the link between previous antibiotics use and the development of cancer.

Elucidating the gut microbiota composition and the bioactivity of immunostimulatory commensals for the optimization of immune checkpoint inhibitors

Accumulating evidence from preclinical studies and human trials demonstrated the crucial role of the gut microbiota in determining the effectiveness of anticancer therapeutics such as immunogenic chemotherapy or immune checkpoint blockade. In summary, it appears that a diverse intestinal microbiota supports therapeutic anticancer responses, while a dysbiotic microbiota composition that lacks immunostimulatory bacteria or contains overabundant immunosuppressive species causes treatment failure. In this review, we explore preclinical and translational studies highlighting how eubiotic and dysbiotic microbiota composition can affect progression-free survival in cancer patients.