Use of broad-spectrum antibiotics impacts outcome in patients treated with immune checkpoint inhibitors

The association between antibiotics use and outcome of cancer patients treated with immune checkpoint inhibitors: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis was to evaluate the impact of antibiotics use on survival of cancer patients with immune checkpoint inhibitors (ICIs).

METHODS

Electronic databases including Pubmed, Emabse, and the Cochrane library were searched. The primary endpoints were overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 20 retrospective studies were included. The median OS (7.9 months versus 17.65 months) and PFS (2.4 months versus 4.4 months) of the antibiotics use group were shorter compared to control group. Meta-analysis also showed that the risks of death (HR = 1.90, 95 % CI: 1.55-2.34; P < 0.01) and disease progression (HR=1.53, 95 % CI: 1.30-1.79; P < 0.01) in antibiotics positive group were significantly higher than that of the negative group. The prognostic role of antibiotics use was still significant regardless of cancer types and timing of antibiotics (P < 0.01 for all).

CONCLUSION

Use of antibiotics may be associated with worse outcomes in cancer patients treated with ICIs.

Cumulative Antibiotic Use Significantly Decreases Efficacy of Checkpoint Inhibitors in Patients with Advanced Cancer

BACKGROUND

With the advent of immunotherapy, substantial progress has been made in improving outcomes for patients with advanced cancer. However, not all patients benefit equally from treatment, and confounding immune-related issues may have an impact. Several studies suggest that antibiotic use (which alters the gut microbiome) may result in poorer outcomes for patients treated with immune checkpoint inhibitors (ICI).

MATERIALS AND METHODS

This is a large, single-site retrospective review of n = 291 patients with advanced cancer treated with ICI (n = 179 melanoma, n = 64 non-small cell lung cancer, and n = 48 renal cell carcinoma). Antibiotic use (both single and multiple courses/prolonged use) during the periods 2 weeks before and 6 weeks after ICI treatment was investigated.

RESULTS

Within this cohort, 92 patients (32%) received antibiotics. Patients who did not require antibiotics had the longest median progression-free survival (PFS), of 6.3 months, and longest median overall survival (OS), of 21.7 months. With other clinically relevant factors controlled, patients who received a single course of antibiotics had a shorter median OS (median OS, 17.7 months; p = .294), and patients who received multiple courses or prolonged antibiotic treatment had the worst outcomes overall (median OS, 6.3 months; p = .009). Progression-free survival times were similarly affected.

CONCLUSION

This large, multivariate analysis demonstrated that antibiotic use is an independent negative predictor of PFS and OS in patients with advanced cancer treated with ICIs. This study highlighted worse treatment outcomes from patients with cumulative (multiple or prolonged courses) antibiotic use, which warrants further investigation and may subsequently inform clinical practice guidelines advocating careful use of antibiotics.

IMPLICATIONS FOR PRACTICE

Antibiotic use is negatively associated with treatment outcomes of immune checkpoint inhibitors (ICI) in advanced cancer. Cumulative antibiotic use is associated with a marked negative survival outcome. Judicious antibiotic prescribing is warranted in patients receiving treatment with ICI for treatment of advanced malignancy.

The effect of antibiotics on clinical outcomes in immune-checkpoint blockade: a systematic review and meta-analysis of observational studies

PURPOSE

Pre-clinical and early clinical data suggests the microbiome plays an important role in oncogenesis and influences response to immune checkpoint blockade (ICB). The objective of this systematic review and meta-analysis was to determine whether antibiotics affect overall survival (OS) and progression free survival (PFS) in patients with solid malignancies treated with ICB.

PATIENTS AND METHODS

A systematic search of EMBASE, MEDLINE and conference proceedings was conducted for observational studies examining the effect of antibiotics on ICB. A random effects study-level meta-analysis was performed with pooling of the hazards ratio (HR) for OS and PFS. Meta-regression was used to determine the impact of the timing of antibiotic exposure on OS.

RESULTS

766 studies were identified, and 18 studies met the inclusion criteria. Of the 2889 patients included, 826 (28.6%) were exposed to antibiotics. The most common malignancies were lung (59%), renal cell carcinoma (RCC) or urothelial carcinoma (16.3%) and melanoma (18.7%). OS was prolonged in those without antibiotic exposure (pooled HR 1.92, 95% CI 1.37-2.68, p < 0.001). The effect of antibiotics on OS was greater in studies defining antibiotic exposure as 42 days prior to initiation of ICB (HR 3.43, 95% CI 2.29-5.14, p < 0.0001). PFS was also longer in patients who did not receive antibiotics (pooled HR 1.65, 95% CI 1.3-2.1, p < 0.0001).

CONCLUSION

In patients receiving ICB, OS and PFS are longer in patients who are not exposed to antibiotics. Antibiotic use in the 42 days before starting ICB appears to be most detrimental to outcome.

Impact of the gut microbiome on immune checkpoint inhibitor efficacy-a systematic review

Background

Immune checkpoint inhibitors (icis) are increasingly being used in clinical practice, improving outcomes for cancer patients. Preclinical models showed significant interaction between the gut microbiome (gm) and response to icis. However, that interaction remains unclear in clinical practice.

Methods

We performed a systematic review in medline to determine■ whether antibiotics affect ici efficacy,■ whether baseline gm composition and ici efficacy show any correlations,■ whether baseline gm composition and emergence of immune-related adverse events (iraes) show any correlations, and■ whether gm manipulation can alleviate the iraes.Included publications had to be written in English or French and had to describe a quantifiable link between gm composition or its modification and the response to icis or the occurrence of iraes, or both.

Results

Of 1451 articles published before December 2018, 13 publications met the inclusion criteria. Five full-text articles and two abstracts highlighted a negative effect of antibiotics on ici efficacy. The composition of the gm was associated with ici efficacy in five full-text articles and one abstract, and with iraes in two full-text articles. In 2 cases, fecal microbiota transplantation was reported to reduce immune colitis.

Conclusions

If possible, antibiotics should be avoided before ici treatment because of their negative effect on ici anticancer efficacy. No specific commensal bacterium was associated with ici efficacy, but an intact gm with high bacterial diversity and a good ratio of "responder-associated" bacteria to "non-responder-associated" bacteria seem to be correlated with better patient outcomes. Fecal microbiota transplantation is a promising technique for reducing ici-associated colitis.

The effect of antibiotics on the clinical outcomes of patients with solid cancers undergoing immune checkpoint inhibitor treatment: a retrospective study

BACKGROUND

This study aimed to assess the effect of antibiotics on the clinical outcomes of patients with solid cancers undergoing treatment with immune checkpoint inhibitors (ICIs).

METHODS

The medical records of 234 patients treated with ICIs for any type of solid cancer between February 2012 and May 2018 at the Seoul St. Mary's Hospital were retrospectively reviewed. The data of patients who received antibiotics within 60 days before the initiation of ICI treatment were analyzed. The patients' responses to ICI treatment and their survival were evaluated.

RESULTS

Non-small-cell lung carcinoma was the most common type of cancer. About half of the patients were treated with nivolumab (51.9%), and cephalosporin (35.2%) was the most commonly used class of antibiotics. The total objective response rate was 21%. Antibiotics use was associated with a decreased objective response (odds ratio 0.466, 95% confidence interval [CI] 0.225-0.968, p = 0.040). The antibiotics group exhibited shorter progression-free survival (PFS) and overall survival (OS) than the no antibiotics group (median PFS: 2 months vs. 4 months, p < 0.001; median OS: 5 months vs. 17 months, p < 0.001). In the multivariate analysis, antibiotics use was a significant predictor of patient survival (PFS: hazard ratio [HR] 1.715, 95% CI 1.264-2.326, p = 0.001; OS: HR 1.785, 95% CI 1.265-2.519, p = 0.001).

CONCLUSIONS

The use of antibiotics may affect the clinical outcomes of patients with solid cancers treated with ICIs. Careful prescription of antibiotics is warranted in candidates who are scheduled for ICI treatment.

TRIAL REGISTRATION

Not applicable (retrospective study).

Antibiotic therapy and outcome from immune-checkpoint inhibitors

Sensitivity to immune checkpoint inhibitor (ICPI) therapy is governed by a complex interplay of tumor and host-related determinants. Epidemiological studies have highlighted that exposure to antibiotic therapy influences the probability of response to ICPI and predict for shorter patient survival across malignancies. Whilst a number of studies have reproducibly documented the detrimental effect of broad-spectrum antibiotics, the immune-biologic mechanisms underlying the association with outcome are poorly understood. Perturbation of the gut microbiota, an increasingly well-characterized factor capable of influencing ICPI-mediated immune reconstitution, has been indicated as a putative mechanism to explain the adverse effects attributed to antibiotic exposure in the context of ICPI therapy. Prospective studies are required to validate antibiotic-mediated gut perturbations as a mechanism of ICPI refractoriness and guide the development of strategies to overcome this barrier to an effective delivery of anti-cancer immunotherapy.

Impact of the microbiome on checkpoint inhibitor treatment in patients with non-small cell lung cancer and melanoma

The microbiome is increasingly recognized for its role in multiple aspects of cancer development and treatment, specifically in response to checkpoint inhibitors. While checkpoint inhibitors have revolutionized cancer treatment by producing durable anti-tumor responses, only a minority of patients respond to the available immunotherapy drugs and accurate, sensitive and specific microbiome predictors of response to treatment remain elusive. Additionally, the specific mechanisms linking the microbiome and host immunological responses remain unclear. In this review, we examine the evidence for the gut microbiome's association with anti-tumor responses to checkpoint inhibitors in the treatment of melanoma, non-small cell lung cancer, and renal cell carcinoma. Furthermore, we discuss the current evidence available from murine models seeking to explain the immunological mechanisms that may drive this process. While this work is promising in defining the impact of gut microbiota in cancer treatment, many unanswered questions indicate the need for additional human and experimental studies.

The negative impact of antibiotics on outcomes in cancer patients treated with immunotherapy: a new independent prognostic factor?

Immune-checkpoint inhibitors (ICI) now represent the standard of care for several cancer types. In pre-clinical models, absence of an intact gut microbiome negatively impacted ICI efficacy and these findings permitted to unravel the importance of the commensal microbiota in immuno-oncology. Recently, multiple clinical studies including more than 1800 patients in aggregate demonstrated the negative predictive impact of treatments with broad-spectrum antibiotics (ATB) on cancer patients receiving ICI. Altogether, these results have led to the hypothesis that ATB-induced dysbiosis might influence the clinical response through the modulation of the gut microbiome. Controversy still remains, as ATB treatment might simply constitute a surrogate marker of unfit or immunodeficient patients. In this review, we summarize recent publications addressing the impact of the gut microbiome on ICI efficacy, discuss currently available data on the effect of ATB administered in different time-frames respect to ICI initiation, and finally, evoke the therapeutic implications of these findings.

Antibiotic use and the efficacy of immune checkpoint inhibitors in cancer patients: a pooled analysis of 2740 cancer patients

The gut microbiota plays a critical role in the anti-tumor immune response. There is increasing data showing that antibiotics (ATBs) change the composition of the gut microbiota and affect the efficacy of immune checkpoint inhibitors (ICIs). However, this is the first meta-analysis to evaluate the association between ATB use and ICI efficacy in cancer patients to provide a better understanding of the strength of this association. We performed a literature search for relevant studies that evaluated the relationship between ATB use and ICI efficacy using the PubMed, Embase, and conference databases. The primary outcomes consisted of overall survival (OS) and progression-free survival (PFS) measured by hazard ratios (HR) and corresponding 95% confidence intervals (CI). Subgroup and sensitivity analyses were also performed. A total of 19 eligible studies comprising 2,740 cancer patients treated with ICIs were included in the analysis. Our results indicated that ATB use was negatively associated with OS in cancer patients (HR = 2.37; 95% CI = 2.05-2.75; P < .001), without heterogeneity (I2 = 0.0%; P = .851). Moreover, ATB use significantly reduced PFS in patients treated with ICIs (HR = 1.84; 95% CI = 1.49-2.26; P < .001; I2 = 56.2%). Similar results were obtained in the subgroup analyses stratified by the time of ATB use and cancer type. Sensitivity analyses confirmed the stability of our results. Therefore, the findings of our meta-analysis indicated that ATB use is negatively associated with OS and PFS in cancer patients treated with ICI immunotherapy.

Intestinal Microbiota: A Novel Target to Improve Anti-Tumor Treatment?

Recently, preclinical and clinical studies targeting several types of cancer strongly supported the key role of the gut microbiota in the modulation of host response to anti-tumoral therapies such as chemotherapy, immunotherapy, radiotherapy and even surgery. Intestinal microbiome has been shown to participate in the resistance to a wide range of anticancer treatments by direct interaction with the treatment or by indirectly stimulating host response through immunomodulation. Interestingly, these effects were described on colorectal cancer but also in other types of malignancies. In addition to their role in therapy efficacy, gut microbiota could also impact side effects induced by anticancer treatments. In the first part of this review, we summarized the role of the gut microbiome on the efficacy and side effects of various anticancer treatments and underlying mechanisms. In the second part, we described the new microbiota-targeting strategies, such as probiotics and prebiotics, antibiotics, fecal microbiota transplantation and physical activity, which could be effective adjuvant therapies developed in order to improve anticancer therapeutic efficiency.

Complex interactions between the microbiome and cancer immune therapy

Immuno-oncology has rapidly grown in the last thirty years, and immunotherapeutic agents are now approved to treat many disparate cancers. Immune checkpoint inhibitors (ICIs) are employed to augment cytotoxic anti-cancer activity by inhibiting negative regulatory elements of the immune system. Modulating the immune system to target neoplasms has improved survivability of numerous cancers in many individuals, but forecasting outcomes post therapy is difficult due to insufficient predictive biomarkers. Recently, the tumor and gastrointestinal microbiome and immune milieu have been investigated as predictors and influencers of cancer immune therapy. In this review, we discuss: (1) ways to measure the microbiome including relevant bioinformatic analyses, (2) recent developments in animal studies and human clinical trials utilizing gut microbial composition and function as biomarkers of cancer immune therapy response and toxicity, and (3) using prebiotics, probiotics, postbiotics, antibiotics, and fecal microbiota transplant (FMT) to modulate immune therapy. We discuss the respective benefits of 16S ribosomal RNA (rRNA) gene and shotgun metagenomic sequencing including important considerations in obtaining samples and in designing and interpreting human and animal microbiome studies. We then focus on studies discussing the differences in response to ICIs in relation to the microbiome and inflammatory mediators. ICIs cause colitis in up to 25% of individuals, and colitis is often refractory to common immunosuppressive medications. Researchers have measured microbiota composition prior to ICI therapy and correlated baseline microbiota composition with efficacy and colitis. Certain bacterial taxa that appear to enhance therapeutic benefit are also implicated in increased susceptibility to colitis, alluding to a delicate balance between pro-inflammatory tumor killing and anti-inflammatory protection from colitis. Pre-clinical and clinical models have trialed probiotic administration, e.g. Bifidobacterium spp. or FMT, to treat colitis when immune suppressive agents fail. We are excited about the future of modulating the microbiome to predict and influence cancer outcomes. Furthermore, novel therapies employed for other illnesses including bacteriophage and genetically-engineered microbes can be adapted in the future to promote increased advancements in cancer treatment and side effect management.

Concomitant medications during immune checkpoint blockage in cancer patients: Novel insights in this emerging clinical scenario

The use of immune checkpoint inhibitors (ICIs) in cancer patients is rapidly growing. However, the potential impact of some widely used concomitant medications is still largely unclear. Emerging data suggest that gut microbiota may affect the efficacy of ICIs, leading to the hypothesis that concurrent antibiotics and proton pump inhibitors use could have a detrimental effect. In addition, steroid use might potentially impair the activity of immunotherapy, due its known immunosuppressive effects, and some safety concerns have been raised in patients receiving commonly used vaccination during ICIs. However, all randomized trials evaluating ICIs consistently excluded patients receiving high corticosteroid doses and data regarding other concomitant medications are lacking. Recently, several retrospective studies have tried to address this unmet medical need. Herein we discuss the latest evidence on the influence of these medications, critically analyzing the data reported so far and the possible implications in our clinical practice.

Baseline Absolute Lymphocyte Count and ECOG Performance Score Are Associated with Survival in Advanced Non-Small Cell Lung Cancer Undergoing PD-1/PD-L1 Blockade

Immune-checkpoint blockade in front-line or second-line treatment improves survival in advanced non-small cell lung cancer (aNSCLC) when compared with chemotherapy alone. However, easily applicable predictive parameters are necessary to guide immune-checkpoint inhibition in clinical practice. In this retrospective bi-centric analysis, we investigated the impact of baseline patient and tumor characteristics on clinical outcome in aNSCLC patients treated with programmed cell death protein 1(PD-1)/programmed cell death ligand 1 (PD-L1) inhibitors. Between May 2015 and January 2018, 142 unselected consecutive NSCLC patients received PD-1/PD-L1 inhibitors during the course of disease. In multivariate analysis, we identified the Eastern Cooperative Oncology Group (ECOG) performance status (ECOG > 1 versus ECOG ≤ 1, HR: 3.23, 95%CI: 1.58-6.60, P = 0.001), baseline absolute lymphocyte count (ALC; high: >0.93 × 109/L versus low: ≤ 0.93 × 109/L, HR: 0.38, 95%CI: 0.23-0.62, P < 0.001), prior or concomitant anti-vascular endothelial growth factor (VEGF) targeting therapy (yes versus no, HR: 2.18, 95%CI: 1.15-4.14, P = 0.017) and TNM stage (IV versus III, HR: 4.18, 95%CI: 1.01-17.36, P = 0.049) as the most relevant parameters for survival. Neither antibiotic exposure (antibiotic-positive versus antibiotic-negative, HR: 0.90, 95%CI: 0.56-1.45, P = 0.675), nor PD-L1 expression on tumor cells (≥1% versus <1%, HR: 0.68, 95%CI: 0.41-1.13, P = 0.140) was associated with survival. Baseline ECOG performance status and ALC were associated with survival in aNSCLC patients treated with PD-1/PD-L1 inhibitors and assessment of these parameters could be suitable in clinical practice.

Cancer Immune Checkpoint Inhibitor Therapy and the Gut Microbiota

The past decade has seen tremendous advances in both our understanding of cancer immunosuppressive microenvironments and colonic bacteria facilitated by immune checkpoint inhibitor antibodies and next generation sequencing, respectively. Because an important role of the host immune system is to communicate with and regulate the gut microbial community, it should not come as a surprise that the behavior of one is coupled to the other. In this review, we will attempt to dissect some of the studies demonstrating cancer immunotherapy modulation by specific gut microbes and discuss possible molecular mechanisms for this effect.