Antibiotics impair immune checkpoint inhibitor effectiveness in Hispanic patients with non-small cell lung cancer (AB-CLICaP)

The Effects of Antibiotics on the Development and Treatment of Non-Small Cell Lung Cancer

There have been studies on antibiotic use concerning lung cancer and its potential impact on carcinogenesis and microbiome. However, subsequent research has failed to support these associations consistently. In terms of the potential carcinogenic of antibiotics on lung cancer, the available evidence has not been sufficient to draw any definitive conclusions. Maintaining immune homeostasis and preventing pathogen invasion is critically dependent on the microbiome. The subtle balance of the body microbiota, including the lungs, is susceptible to disruption by antibiotic use. There is an association between disruptions of the lung microbiome and respiratory diseases, including lung cancer, and decreased efficacy of treatments. Patients with lung cancer are often indicated for antibiotic treatment due to respiratory infections or other comorbidities. Pulmonary infections in the area of undetected lung tumors are not uncommon. They can be an early sign of malignancy, which may explain the association between antibiotic use and lung cancer diagnosis. Antibiotic use can also affect the effectiveness of immune checkpoint inhibitor therapy. Studies suggest that antibiotic use can impair the efficacy of immune checkpoint inhibitor therapy in lung cancer patients, particularly around the time when treatment is initiated. These findings require further study, understanding underlying mechanisms, and identifying microbiota signatures associated with treatment response.

Lung microbiome: an emerging player in lung cancer pathogenesis and progression

The microbiome of the lungs, although until recently neglected, is now emerging as a potential contributor to chronic lung diseases, including cancer. Preclinical evidence suggests that the microbial burden of the lungs shapes the host immunity mechanisms and affects local antitumor immune responses. Studies of cohorts of patients with lung cancer reveal that different microbiome profiles are detected in patients with lung cancer compared to controls. In addition, an association between differential lung microbiome composition and distinct responses to immunotherapy has been suggested, yet, with limited data. Scarce evidence exists on the role of the lung microbiome in the development of metastases in the lungs. Interestingly, the lung microbiome is not isolated and interacts with the gut microbiome through a dynamic axis. Future research on the involvement of the lung microbiome in lung cancer pathogenesis and potential therapeutic implications is greatly anticipated.

Intratumoral bacteria are an important "accomplice" in tumor development and metastasis

As emerging tumor components, intratumoral bacteria have been found in many solid tumors. Several studies have demonstrated that different cancer subtypes have distinct microbial compositions, and mechanistic studies have shown that intratumoral bacteria may promote cancer initiation and progression through DNA damage, epigenetic modification, inflammatory responses, modulation of host immunity and activation of oncogenes or oncogenic pathways. Moreover, intratumoral bacteria have been shown to modulate tumor metastasis and chemotherapy response. A better understanding of the tumor microenvironment and its associated microbiota will facilitate the design of new metabolically engineered species, opening up a new era of intratumoral bacteria-based cancer therapy. However, many questions remain to be resolved, such as where intratumoral bacteria originate and whether there is a direct causal relationship between intratumoral bacteria and tumor susceptibility. In addition, suitable preclinical models and more advanced detection techniques are crucial for studying the biological functions of intratumoral bacteria. In this review, we summarize the complicated role of intratumoral bacteria in the regulation of cancer development and metastasis and discuss their carcinogenic mechanisms and potential therapeutic aspects.

A systematic review and meta-analysis evaluating the impact of antibiotic use on the clinical outcomes of cancer patients treated with immune checkpoint inhibitors

Background

Immune checkpoint inhibitors (ICIs) have considerably improved patient outcomes in various cancer types, but their efficacy remains poorly predictable among patients. The intestinal microbiome, whose balance and composition can be significantly altered by antibiotic use, has recently emerged as a factor that may modulate ICI efficacy. The objective of this systematic review and meta-analysis is to investigate the impact of antibiotics on the clinical outcomes of cancer patients treated with ICIs.

Methods

PubMed and major oncology conference proceedings were systematically searched to identify all studies reporting associations between antibiotic use and at least one of the following endpoints: Overall Survival (OS), Progression-Free Survival (PFS), Objective Response Rate (ORR) and Progressive Disease (PD) Rate. Pooled Hazard Ratios (HRs) for OS and PFS, and pooled Odds Ratios (ORs) for ORR and PD were calculated. Subgroup analyses on survival outcomes were also performed to investigate the potential differential effect of antibiotics according to cancer types and antibiotic exposure time windows.

Results

107 articles reporting data for 123 independent cohorts were included, representing a total of 41,663 patients among whom 11,785 (28%) received antibiotics around ICI initiation. The pooled HRs for OS and PFS were respectively of 1.61 [95% Confidence Interval (CI) 1.48-1.76] and 1.45 [95% CI 1.32-1.60], confirming that antibiotic use was significantly associated with shorter survival. This negative association was observed consistently across all cancer types for OS and depending on the cancer type for PFS. The loss of survival was particularly strong when antibiotics were received shortly before or after ICI initiation. The pooled ORs for ORR and PD were respectively of 0.59 [95% CI 0.47-0.76] and 1.86 [95% CI 1.41-2.46], suggesting that antibiotic use was significantly associated with worse treatment-related outcomes.

Conclusion

As it is not ethically feasible to conduct interventional, randomized, controlled trials in which antibiotics would be administered to cancer patients treated with ICIs to demonstrate their deleterious impact versus control, prospective observational studies and interventional trials involving microbiome modifiers are crucially needed to uncover the role of microbiome and improve patient outcomes. Such studies will reduce the existing publication bias by allowing analyses on more homogeneous populations, especially in terms of treatments received, which is not possible at this stage given the current state of the field. In the meantime, antibiotic prescription should be cautiously considered in cancer patients receiving ICIs.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42019145675.

Conversion of unresponsiveness to immune checkpoint inhibition by fecal microbiota transplantation in patients with metastatic melanoma: study protocol for a randomized phase Ib/IIa trial

BACKGROUND

The gut microbiome plays an important role in immune modulation. Specifically, presence or absence of certain gut bacterial taxa has been associated with better antitumor immune responses. Furthermore, in trials using fecal microbiota transplantation (FMT) to treat melanoma patients unresponsive to immune checkpoint inhibitors (ICI), complete responses (CR), partial responses (PR), and durable stable disease (SD) have been observed. However, the underlying mechanism determining which patients will or will not respond and what the optimal FMT composition is, has not been fully elucidated, and a discrepancy in microbial taxa associated with clinical response has been observed between studies. Furthermore, it is unknown whether a change in the microbiome itself, irrespective of its origin, or FMT from ICI responding donors, is required for reversion of ICI-unresponsiveness. To address this, we will transfer microbiota of either ICI responder or nonresponder metastatic melanoma patients via FMT.

METHODS

In this randomized, double-blinded phase Ib/IIa trial, 24 anti-PD1-refractory patients with advanced stage cutaneous melanoma will receive an FMT from either an ICI responding or nonresponding donor, while continuing anti-PD-1 treatment. Donors will be selected from patients with metastatic melanoma treated with anti-PD-1 therapy. Two patients with a good response (≥ 30% decrease according to RECIST 1.1 within the past 24 months) and two patients with progression (≥ 20% increase according to RECIST 1.1 within the past 3 months) will be selected as ICI responding or nonresponding donors, respectively. The primary endpoint is clinical benefit (SD, PR or CR) at 12 weeks, confirmed on a CT scan at 16 weeks. The secondary endpoint is safety, defined as the occurrence of grade ≥ 3 toxicity. Exploratory endpoints are progression-free survival and changes in the gut microbiome, metabolome, and immune cells.

DISCUSSION

Transplanting fecal microbiota to restore the patients' perturbed microbiome has proven successful in several indications. However, less is known about the potential role of FMT to improve antitumor immune response. In this trial, we aim to investigate whether administration of FMT can reverse resistance to anti-PD-1 treatment in patients with advanced stage melanoma, and whether the ICI-responsiveness of the feces donor is associated with its effectiveness.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05251389 (registered 22-Feb-2022). Protocol V4.0 (08-02-2022).

Broad-spectrum antibiotics associated gut microbiome disturbance impairs T cell immunity and promotes lung cancer metastasis: a retrospective study

Background

Gut microbiome has been linked to a regulatory role in cancer progression. However, whether broad-spectrum antibiotics (ATB) associated gut microbiome dysbiosis contributes to an impaired T cell immune function, and ultimately promotes lung cancer metastasis is not well known.

Methods

In this study, a retrospective analysis was performed in a cohort of 263 patients initially diagnosed with non-small cell lung cancer (NSCLC) patients, including the ATB group (patients with broad-spectrum antibiotics treatment) (n = 124), and non-ATB group (n = 139) as control. ATB patients were prescribed ATB for over 5 days within 30 days prior to the collection of blood and fecal specimens and followed surgical treatment or first-line therapy. T cell immune function and metastasis-free survival (MFS) were evaluated between the two groups. Gut microbiota was evaluated by 16S rDNA sequencing. The predictive value of T cell immunity for MFS was evaluated by ROC analysis and Cox regression analysis.

Results

Our results suggest that broad-spectrum antibiotics (ATB) impair T cell immune function in patients with either early-stage or advanced NSCLC, which likely contribute to the promotion of lung cancer metastasis. Results of the survival analysis show that metastasis-free survival (MFS) is significantly shorter in the ATB patients than that in the non-ATB patients with stage III NSCLC. The 16S rDNA sequencing shows that ATB administration contributes to a significant dysbiosis of the composition and diversity of gut microbiota. Moreover, ROC analysis results of CD4 (AUC 0.642, p = 0.011), CD8 (AUC was 0.729, p < 0.001), CD16 + 56 + (AUC 0.643, p = 0.003), and the combination of CD4, CD8 and CD16 + 56+ (AUC 0.810, p < 0.001), or Cox regression analysis results of CD4 (HR 0.206, p < 0.001), CD8 (HR 0.555, p = 0.009), which is likely regulated by ATB administration, have significantly predictive values for MFS.

Conclusion

These results provide evidence of gut microbiome disturbance due to ATB administration is involved in the regulation of T cell immunity, and their predictive value for the tumor metastasis in lung cancer patients. Thus, gut microbiota may serve as a therapeutic target for lung cancer. Consequently, caution should be exercised before the long-term administration of broad-spectrum antibiotics in cancer patients.

Flausino L, Iyer G, Balkrishnan R. Effectiveness of immunological agents in non-small cell lung cancer

BACKGROUND AND AIM

Non-small cell lung cancer (NSCLC) continues to claim millions of lives worldwide. Although its poor prognosis is largely attributed to the lack of adequate and precise detection technologies, cancer cells' suppression of the immune system adds on to the difficulty of identifying abnormal NSCLC tumors in their early stages. Therefore, cancer immunotherapy, which activates the immune system and helps it fight tumors, has recently become the most sought-after technique, especially in the advanced stages of NSCLC, where surgery or chemotherapy may or may not bring about the desired survival benefits in patients.

METHODS

This review focuses on the various immunotherapeutic interventions and their efficacy in advanced NSCLC clinical trials. Monoclonal antibodies like anti-PD-1/PD-L1 agents and anti-CTLA-4 antibodies, cancer vaccines, oncolytic viruses and adoptive T cell therapy have been discussed in brief. Furthermore, the effects of gender, age, and race on the efficacy of immune checkpoint inhibitors and suggest plausible future approaches in the realm of immuno-oncology.

RESULTS

Immunotherapy is used alone or in combination either with other immunological agents or with chemotherapy. However, the efficacy of these strategies depends extensively on various demographic variables, as some patients respond perfectly well to immunotherapy, while others do not benefit at all or experience disease progression. By targeting a "hallmark" of cancer (immune evasion), immunotherapy has transformed NSCLC management, though several barriers prevent its complete effectiveness.

CONCLUSIONS

All these immunological strategies should be interpreted in the current setting of synergistic treatment, in which these agents can be combined with chemotherapy, radiotherapy, and, or surgery following patient and tumor characteristics to proportionate the best-individualized treatment and achieve superior results. To better pursue this goal, further investigations on cost-effectiveness and sex-gender, race, and age differences in immunotherapy are needed.

Persistent ethnicity-associated disparity in anti-tumor effectiveness of immune checkpoint inhibitors despite equal access

We reviewed response to immune checkpoint inhibitors (ICI) of 207 patients with diagnoses of lung or head and neck cancer treated with chemotherapy/ICI combination therapy and ICI monotherapy between 2015 and 2020 at one of three clinical pavilions associated with the Dan L. Duncan Comprehensive Cancer Center at Baylor College of Medicine. Two of these pavilions (Harris Health System and the Michael E. DeBakey Veterans Affairs Medical Center) serve large minority populations and provide equal access to care regardless of means. 174 patients had a diagnosis of lung cancer (non-small cell or small cell) and 33 had a diagnosis of head and neck squamous cell carcinoma (HNSCC). 38% self-identified as Black, 45% as non-Hispanic White, and 18% as Hispanic. The objective response rate (ORR) was similar for lung cancer (35.057%) and HNSCC patients (30.3%) (p=0.894). The ORR for Hispanic and Black patients was lower compared to non-Hispanic White patients (H 27.0%, B 32.5%, W 38.7%; H vs. W p=0.209; B vs. W p=0.398). When considering only patients treated with ICI monotherapy, the ORR for Hispanic patients dropped further to 20.7% while the ORR of Black and non-Hispanic White patients remained about the same (B 29.3% and W 35.9%, H vs. W p=0.133; B vs. W p=0.419). Immune related adverse events were the lowest in the Hispanic population occurring in only 30% of patients compared to 40% of patients in the Black cohort and 50% of the non-Hispanic White cohorts.

Pyroptosis-related lncRNAs are potential biomarkers for predicting prognoses and immune responses in patients with UCEC

Uterine corpus endometrial carcinoma (UCEC) is a malignant disease globally, and there is no unified prognostic signature at present. In our study, two clusters were identified. Cluster 1 showed better prognosis and higher infiltration level, such as tumor microenvironment (TME), tumor mutation burden (TMB), and immune checkpoint genes expression. Gene set enrichment analysis (GSEA) indicated that some tumor-related pathways and immune-associated pathways were exposed. What is more, six pyroptosis-related long noncoding RNAs (lncRNAs) (PRLs) were applied to establish a prognostic signature through multiple Cox regression analysis. In both training and testing sets, patients with higher risk score had poorer survival than patients with low risk. The area under the curve (AUC) of receiver operating characteristic (ROC) curves performed that the survival probability was better in people with lower risk score. Mechanism analysis revealed that high risk score was correlated with reduced immune infiltration and T cells exhaustion, matching the definition of an "immune-desert" phenotype. Patients with lower risk score were characterized by higher immune checkpoint gene expression and TMB and have a sensitive response to immunotherapy and chemotherapy compared with patients with high risk score. The signature has accurate prediction ability of UCEC and is a promising therapeutic target to improve the effect of immunotherapy.

The Emerging Role of the Gut Microbiome in the Cancer Response to Immune Checkpoint Inhibitors: A Narrative Review

The discovery of immune checkpoint inhibitors (ICIs) has revolutionized the care of cancer patients. However, the response to ICI therapy exhibits substantial interindividual variability. Efforts have been directed to identify biomarkers that predict the clinical response to ICIs. In recent years, the gut microbiome has emerged as a critical player that influences the efficacy of immunotherapy. An increasing number of studies have suggested that the baseline composition of a patient's gut microbiota and its dysbiosis are correlated with the outcome of cancer immunotherapy. This review tackles the rapidly growing body of evidence evaluating the relationship between the gut microbiome and the response to ICI therapy. Additionally, this review highlights the impact of antibiotic-induced dysbiosis on ICI efficacy and discusses the possible therapeutic interventions to optimize the gut microbiota composition to augment immunotherapy efficacy.

Impact of antibiotic treatment on immunotherapy response in women with recurrent gynecologic cancer

OBJECTIVE(S)

To identify whether antibiotics (ABX) impact immunotherapy (ICI) response rate (RR), progression-free survival (PFS), and overall survival (OS) in women with recurrent endometrial (EC), cervical (CC) and ovarian cancer (OC).

METHODS

This retrospective cohort study included women with recurrent EC, CC, and OC treated with ICIs from 1/1/17-9/1/2020. ABX were defined as 30 days before (pABX) or concurrently (cABX) with ICI. The impact of ABX upon PFS and OS was assessed by univariate analysis and multivariable Cox regression.

RESULTS

Of 101 women, 52.5% (n = 53) had recurrent EC, 21.4% (n = 22) CC and 25.7% (n = 26) OC. 56.9% (n = 58) received ABX, with 22.8% (n = 23) pABX and 46.5% (n = 47) cABX. While no difference was observed in ICI RR for any ABX vs. none (p = 0.89) and cABX vs. none (p = 0.33), pABX (n = 23) were associated with decreased RR vs. none (n = 78) (Partial Response - 8.7% vs. 30.8%; Complete Response - 4.3% vs. 9.0%; p = 0.002). On univariate analysis, pABX were associated with worsened PFS (2.9 vs. 8.9 months; HR 2.53, 95% CI 1.48-4.31, p < 0.001) and OS (9.3 vs. 19.9 months; HR 2.29, 95% CI 1.22-4.32, p = 0.01). No PFS or OS difference was noted for cABX (PFS - 9.3 vs. 6.0 months; HR 0.70, 95% CI 0.43-1.12; p = 0.14; OS - 13.4 vs. 16.3 months; HR 0.89, 95% CI 0.51-1.54; p = 0.68). On multivariable analysis, pABX were associated with significantly decreased PFS (HR 3.10, 95% CI 1.75-5.49, p < 0.001) and OS (HR 3.03, 95% CI 1.50-6.10, p = 0.002).

CONCLUSIONS

In women with recurrent EC, OC, and CC receiving ICI, pABX, but not cABX, are associated with decreased RR, PFS, and OS. Further investigation is warranted to understand predictors of ICI response in women with gynecologic cancer.