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

Shenqi Fuzheng injection modulates tumor fatty acid metabolism to downregulate MDSCs infiltration, enhancing PD-L1 antibody inhibition of intracranial growth in Melanoma

BACKGROUND

Addressing brain metastases in cancer presents substantial challenges due to limited therapeutic options and high mortality rates. In clinical practice, the amalgamation of traditional Chinese medicine with other treatment modalities has exhibited noteworthy efficacy in managing disease progression and enhancing quality of life.

OBJECTIVE

To substantiate the regulatory effects of Shenqi Fuzheng Injection (SFI) on the microenvironment of melanoma brain metastases and appraise whether SFI augments the anti-tumour effects of immune checkpoint inhibitors, with a specific focus on investigating the mechanisms underlying SFI's actions.

METHODS

Initially, we established a B16-F10 brain transplant tumour model in C57BL/6 mice using a stereotaxic apparatus. The efficacy of the drug was evaluated through in vivo imaging technology, HE staining, and immunofluorescence. Mass Cytometry (CyTOF) and flow cytometry were employed to analyse the impact of SFI on immune cell subpopulations in the tumour microenvironment. Subsequently, transcriptome sequencing and metabolomics were utilised to examine the effects of SFI on melanoma-related genes and metabolism. Molecular docking, Western Blot, and ELISA assays were conducted to investigate the targets of SFI in intervening in melanoma fatty acid metabolism. Finally, the anti-tumour effects of SFI in combination with immune checkpoint inhibitors were scrutinised in the brain transplant tumour model.

RESULTS

The pharmacological findings demonstrated that SFI inhibits the growth of melanoma brain transplant tumours in a dose-dependent manner. CyTOF, flow cytometry, and immunofluorescence results revealed that SFI significantly diminishes the levels of Myeloid-Derived Suppressor Cells (MDSCs) and Regulatory T cells (Tregs) in the tumour microenvironment while enhancing the levels of CD8+T and CD4+ T cells. Subsequently, transcriptomic and metabolomic findings, both in vitro and in vivo, indicate that SFI significantly inhibits the arachidonic acid metabolism process in melanoma cells. Molecular docking and biological experiments showed that SFI inhibits the expression of D6D and the activity of COX-2, leading to a reduction in downstream PGE2 production. Lastly, SFI significantly enhances the anti-tumour effects of PD-L1 antibody against intracranial melanoma.

CONCLUSION

SFI improves the tumour immune microenvironment in melanoma by intervening in fatty acid metabolism, thereby reducing levels of MDSCs and Tregs while increasing levels of CD8+ T and CD4+ T cells. Ultimately, this augmentation leads to enhanced anti-tumour effects of the immune checkpoint inhibitor PD-L1 antibody.

Predictive Factors in Metastatic Melanoma Treated with Immune Checkpoint Inhibitors: From Clinical Practice to Future Perspective

The introduction of immunotherapy revolutionized the treatment landscape in metastatic melanoma. Despite the impressive results associated with immune checkpoint inhibitors (ICIs), only a portion of patients obtain a response to this treatment. In this scenario, the research of predictive factors is fundamental to identify patients who may have a response and to exclude patients with a low possibility to respond. These factors can be host-associated, immune system activation-related, and tumor-related. Patient-related factors can vary from data obtained by medical history (performance status, age, sex, body mass index, concomitant medications, and comorbidities) to analysis of the gut microbiome from fecal samples. Tumor-related factors can reflect tumor burden (metastatic sites, lactate dehydrogenase, C-reactive protein, and circulating tumor DNA) or can derive from the analysis of tumor samples (driver mutations, tumor-infiltrating lymphocytes, and myeloid cells). Biomarkers evaluating the immune system activation, such as IFN-gamma gene expression profile and analysis of circulating immune cell subsets, have emerged in recent years as significantly correlated with response to ICIs. In this manuscript, we critically reviewed the most updated literature data on the landscape of predictive factors in metastatic melanoma treated with ICIs. We focus on the principal limits and potentiality of different methods, shedding light on the more promising biomarkers.

Hyperprogressive disease during PD-1 blockade in patients with advanced pancreatic cancer

The occurrence of markedly accelerated tumor growth during immunotherapy is considered a new mode of progression called hyperprogressive disease (HPD) and its impact on pancreatic cancer (PC) patients receiving immunotherapy is unknown. In this study, we described and explored the incidence, prognosis and predictors of HPD in patients with advanced PC treated with programmed cell death-1 (PD-1) inhibitors. We retrospectively analyzed clinicopathological data from 104 patients with advanced pancreatic cancer who were treated with PD-1 inhibitors at our institution during 2015-2020 and identified 10 (9.6%) patients with HPD. Overall survival (OS) was significantly poorer in patients with HPD compared to patients with progressive disease (PD) (median OS: 5.6 vs. 3.6 months, p < .01). Clinicopathological factors associated with the occurrence of HPD included smoking, metastatic sites >2, liver metastasis, antibiotic therapy within 21 days before immunotherapy (Abx B21), hemoglobin (Hb) level <110 g/L, and PD-1 inhibitor treatment line >2. Subgroup analysis showed that high levels of CA19-9 at baseline were associated with the development of subsequent HPD (p = .024) and a worse prognosis (mOS:16.2 months vs. 6.1 months, p < .01). Our study demonstrated that HPD may occur in PC patients treated with PD-1 inhibitors and is associated with several clinicopathological characteristics and poor prognosis. The baseline tumor marker CA19-9 may be one of the early predictors of HPD development in PC patients receiving immunotherapy.

Antimicrobial exposure is associated with decreased survival in triple-negative breast cancer

Antimicrobial exposure during curative-intent treatment of triple-negative breast cancer (TNBC) may lead to gut microbiome dysbiosis, decreased circulating and tumor-infiltrating lymphocytes, and inferior outcomes. Here, we investigate the association of antimicrobial exposure and peripheral lymphocyte count during TNBC treatment with survival, using integrated electronic medical record and California Cancer Registry data in the Oncoshare database. Of 772 women with stage I-III TNBC treated with and without standard cytotoxic chemotherapy - prior to the immune checkpoint inhibitor era - most (654, 85%) used antimicrobials. Applying multivariate analyses, we show that each additional total or unique monthly antimicrobial prescription is associated with inferior overall and breast cancer-specific survival. This antimicrobial-mortality association is independent of changes in neutrophil count, is unrelated to disease severity, and is sustained through year three following diagnosis, suggesting antimicrobial exposure negatively impacts TNBC survival. These results may inform mechanistic studies and antimicrobial prescribing decisions in TNBC and other hormone receptor-independent cancers.

The concomitant use of proton pump inhibitors and BRAF/MEK inhibitors in metastatic melanoma

BACKGROUND

Proton-pump inhibitors (PPIs) are commonly used by patients with cancer, although they could reduce the absorption of oral anticancer targeted therapies. The US Food and Drug Administration states that the effect of PPIs on the efficacy of dabrafenib use by patients with metastatic melanoma is unknown. As a precautionary measure, the European Society for Medical Oncology recommends avoiding PPIs for patients receiving dabrafenib.

OBJECTIVES

To determine the effect of the concomitant use of PPIs and BRAF/MEK inhibitors in patients with metastatic melanoma.

METHODS

Patients with advanced melanoma receiving BRAF/MEK inhibitors as first-line treatments between 2015 and 2017 in France were selected using the French National Health Insurance database. We compared time-to-treatment discontinuation (TTD) and overall survival (OS) according to concomitant PPI exposure. We balanced the baseline characteristics of patients exposed and nonexposed to PPIs using an overlap weighting method based on a propensity score.

RESULTS

The metastatic melanoma cohort comprised 1028 patients receiving BRAF/MEK inhibitors, including 361 (35.1%) patients using PPIs. PPI users had more comorbidities and a more severe metastatic disease. After having equally distributed metastatic sites and comorbidities across patients exposed and nonexposed to PPIs, concomitant PPI use was not associated with shorter TTD [weighted hazard ratio (wHR) 1.03, 95% confidence interval (CI) 0.86-1.24] or OS (wHR 1.11, 95% CI 0.88-1.39). Consistent results were observed when restricting the population to patients receiving dabrafenib, or when narrowing exposure to PPIs with stronger inhibition of cytochromes.

CONCLUSIONS

In a population-based cohort of patients with advanced melanoma, the concomitant use of PPIs and BRAF/MEK inhibitors was not associated with worse outcome.

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.