Statins and immune checkpoint inhibitors: a strategy to improve the efficacy of immunotherapy for cancer?

Unraveling the link between cholesterol and immune system in cancer: From biological mechanistic insights to clinical evidence. A narrative review

Cholesterol and its metabolism seem to be involved not only in cancer progression but also in immune cells activity. In this comprehensive review, we summarize preclinical, translational, and clinical evidence regarding the crucial role of cholesterol and its metabolism in regulating the immune response against cancer cells, shedding light on the multifaceted mechanisms by which cholesterol influences immune cell function and anti-tumor immunity. By synthesizing findings from preclinical studies, we have elucidated the impact of cholesterol on immune cell activation, differentiation, and effector functions. These investigations have revealed that cholesterol metabolism plays a pivotal role in shaping the immune response, with alterations in cholesterol levels directly impacting immune cell behavior and anti-tumor activity. All the steps related to cholesterol metabolism, including its de-novo synthesis, its influx and efflux mechanisms, as well as its metabolites, have a distinct impact on immune cells function and activity, which, if altered, might influence tumor progression. In addition, we have reviewed clinical studies investigating the role of circulating cholesterol on outcomes of patients with advanced tumors treated with immune checkpoint inhibitors, highlighting again in a clinical scenario the correlation between cholesterol and the immune system. Overall, our review emphasizes the importance of cholesterol and its metabolism in orchestrating the immune response against cancer cells. Herein we have provided a comprehensive overview of this emerging field by illustrating the intricate interplay between cholesterol and immune system.

The Effect of PD-1/PD-L1 Inhibitor and Statin Combination Therapy on Overall Survival and Gastrointestinal Toxicity

OBJECTIVES

Immune checkpoint inhibitors (ICIs), such as programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors, have been approved to treat a variety of cancers. Recently, studies have suggested that ICIs and statins are synergistic. However, the addition of statins to ICI therapy may increase the risk of gastrointestinal immune-related adverse events (irAEs). We investigated the effect of combination therapy with PD-1 and/or L1 inhibitors and statins on overall survival and gastrointestinal irAEs.

METHODS

We reviewed the charts of patients with select cancers who received PD-1 and/or PD-L1 inhibitors and statins. The incidence of gastrointestinal irAEs and overall survival were compared with that in a matched control group of patients who received PD-1 and/or PD-L1 inhibitors without statins.

RESULTS

Of the 823 patients in the statin group, 707 received PD-1 inhibitors, 86 received PD-L1 inhibitors, and 30 received both. Patients taking any statins (10.8%) and those taking high-intensity statins (15.8%) had higher rates of gastrointestinal irAEs than patients not taking statins (8.7%; P =0.046 and 0.006, respectively). Compared with the nonstatin treatments, statin use was associated with improved overall survival for patients taking PD-1 inhibitors ( P <0.001) and for patients with ( P =0.021) and without ( P <0.001) gastrointestinal irAEs.

CONCLUSIONS

Synergism of statins with PD-1 and PD-L1 inhibitors continues to be a developing field of interest. Our data demonstrate the survival benefit of combination therapy with PD-1 and/or PD-L1 inhibitors and statins, warranting further investigation.

Concomitant Statin Use and Survival in Patients With Cancer on Immune Checkpoint Inhibitors: A Meta-Analysis

PURPOSE

The prognostic significance of concomitant statin use in cancer treatment with immune checkpoint inhibitors (ICIs) remains a subject of ongoing investigation. This study aims to clarify the prognostic value of statin use in this patient population and to provide a robust, evidence-based foundation to guide therapeutic decisions.

METHODS

A systematic search strategy was used across a multitude of digital archives to exhaustively identify all relevant academic literature published up until June 20, 2024. Studies published in English that reported hazard ratios (HRs) for overall survival (OS) and/or progression-free survival (PFS), along with corresponding 95% CIs, were considered eligible for inclusion. Meta-analyses were conducted to calculate combined HRs with 95% CIs.

RESULTS

A total of 25 studies, involving 46,154 patients with cancer, were included in the meta-analysis. The pooled results indicated that concomitant statin use was linked to better OS (HR, 0.80 [95% CI, 0.71 to 0.92]) and PFS (HR, 0.80 [95% CI, 0.69 to 0.92]) in patients with cancer under ICI therapy. Sensitivity analyses further validated the consistency and robustness of the combined results.

CONCLUSION

On the basis of the available clinical evidence, the concomitant use of statin is linked to an improved prognosis in oncology patients on ICI-based therapy. These observations underscore the potential of statin as an important adjunctive therapy in the treatment paradigm for ICI-treated patients with cancer, thereby establishing their significance as a key consideration in clinical management strategies. Further randomized controlled trials are imperative to validate the effect of statin use within the realm of ICI therapy.

Atherosclerosis and the Bidirectional Relationship Between Cancer and Cardiovascular Disease: From Bench to Bedside, Part 2 Management

The first part of this review highlighted the evolving landscape of atherosclerosis, noting emerging cardiometabolic risk factors, the growing impact of exposomes, and social determinants of health. The prominent role of atherosclerosis in the bidirectional relationship between cardiovascular disease and cancer was also discussed. In this second part, we examine the complex interplay between multimorbid cardio-oncologic patients, cardiometabolic risk factors, and the harmful environments that lend a "syndemic" nature to these chronic diseases. We summarize management strategies targeting disordered cardiometabolic factors to mitigate cardiovascular disease and explore molecular mechanisms enabling more tailored therapies. Importantly, we emphasize the early interception of atherosclerosis through multifactorial interventions that detect subclinical signs (via biomarkers and imaging) to treat modifiable risk factors and prevent clinical events. A concerted preventive effort-referred to by some as a "preventome"-is essential to reduce the burden of atherosclerosis-driven chronic diseases, shifting from mere chronic disease management to the proactive promotion of "chronic health".

The impact of statins on melanoma survival: a systematic review and meta-analysis

Statin use may decrease recurrence and improve survival in patients with melanoma. In this systematic review and meta-analysis, we examine the current body of literature concerning the use of statins as an adjunctive therapy in melanoma, Medline, EMBASE, CENTRAL, and PubMed were systematically searched from inception through to April 2023. Studies were included if they compared patients with melanoma receiving and not receiving statin therapy concurrently with their oncologic treatment in terms of long-term oncologic outcomes. The primary outcome was 5-year overall survival (OS). Meta-analyses was performed with DerSimonian and Laird random effects. Risk of bias was assessed with the ROBINS-I and GRADE was used to assess certainty of evidence. From 952 citations, eight non-randomized studies were identified. Included studies were conducted between 2007 and 2022. Random effects meta-analysis of adjusted hazard ratios from three studies suggested an improvement in 5-year OS with statin use with wide 95% confidence intervals (CIs) crossing the line of no effect (hazard ratio 0.87, 95% CI: 0.73-1.04, P  = 0.12, I2  = 95%, very-low certainty). Outcome reporting was heterogeneous across all other oncologic outcomes such that pooling of data was not possible. Risk of bias was serious for seven studies and moderate for one study. This systematic review of studies evaluating the impact of statin use on survival in patients with melanoma found a 13% reduction in risk of death at 5 years from diagnosis - a point estimate suggesting benefit. However, the wide 95% CIs and resultant type II error risk create significant uncertainty.

Effect of Statin Lipophilicity on the Proliferation of Hepatocellular Carcinoma Cells

The HMG-CoA reductase inhibitors, statins, are drugs used globally for lowering the level of cholesterol in the blood. Different clinical studies of statins in cancer patients have indicated a decrease in cancer mortality, particularly in patients using lipophilic statins compared to those on hydrophilic statins. In this paper, we selected two structurally different statins (simvastatin and pravastatin) with different lipophilicities and investigated their effects on the proliferation and apoptosis of hepatocellular carcinoma cells. Lipophilic simvastatin highly influences cancer cell growth and survival in a time- and concentration-dependent manner, while pravastatin, due to its hydrophilic structure and limited cellular uptake, showed minimal cytotoxic effects.

Concurrent Use of Statins in Patients Undergoing Curative Intent Treatment for Triple Negative Breast Cancer: A Systematic Review and Meta-Analysis

Pre-clinical studies in triple negative breast cancer (TNBC) suggest that statins may inhibit cell proliferation, promote cell-cycle arrest, induce apoptosis, change the tumor microenvironment, and improve effectiveness of other therapies. Observational studies have demonstrated variable effects from statin therapy on oncologic outcomes in these patients. As such, we aimed to pool previous data via a systematic review and meta-analysis to elucidate the impact of concurrent statin use on oncologic outcomes for patients with TNBC. Medline, EMBASE, CENTRAL, and PubMed were systematically searched from inception through to June 2022. Studies were included if they compared patients with TNBC receiving and not receiving statin therapy concurrently with oncologic treatment for curative intent in terms of recurrence and survival in a non-metastatic setting. The primary outcomes were 5-year disease-free survival (DFS) and 5-year overall survival (OS). A pairwise meta-analyses was performed using inverse variance random effects. Risk of bias was assessed with the ROBINS-I and the GRADE approach was conducted to assess quality of evidence. From 4014 citations, 5 studies with 625 patients on statin therapy and 2707 patients not on statin therapy were included. There was a significant increase in 5-year DFS for patients on statin therapy compared to patients not on statin therapy (OR 1.44, 95% CI 1.04-1.98, P = .03). No significant difference was noted in 5-year OS between the 2 groups (OR 1.12, 95% CI 0.86-1.47, P = .40). Included studies were at moderate-to-high risk of bias. The GRADE quality of evidence was very low. This review presents very low-quality evidence that concurrent use of statins with oncologic treatment may potentially improve long-term DFS for patients with TNBC undergoing curative intent therapy. Future research by way of large, prospective study is required to further clarify the clinical utility of statins on patients undergoing treatment for TNBC.

Immune Response and Metastasis-Links between the Metastasis Driver MACC1 and Cancer Immune Escape Strategies

Metastasis remains the most critical factor limiting patient survival and the most challenging part of cancer-targeted therapy. Identifying the causal drivers of metastasis and characterizing their properties in various key aspects of cancer biology is essential for the development of novel metastasis-targeting approaches. Metastasis-associated in colon cancer 1 (MACC1) is a prognostic and predictive biomarker that is now recognized in more than 20 cancer entities. Although MACC1 can already be linked with many hallmarks of cancer, one key process-the facilitation of immune evasion-remains poorly understood. In this review, we explore the direct and indirect links between MACC1 and the mechanisms of immune escape. Therein, we highlight the signaling pathways and secreted factors influenced by MACC1 as well as their effects on the infiltration and anti-tumor function of immune cells.

Prognostic Impact of Blood Lipid Profile in Patients With Advanced Solid Tumors Treated With Immune Checkpoint Inhibitors: A Multicenter Cohort Study

BACKGROUND

Specific components of lipid profile seem to differently impact on immune activity against cancer and unraveling their prognostic role in patients with solid cancer treated with immune checkpoint inhibitors (ICIs) is needed.

MATERIALS AND METHODS

We retrospectively collected baseline clinicopathological characteristics including circulating lipid profile (total cholesterol [TC], triglycerides [TG], low-density lipoproteins [LDL], high-density lipoproteins [HDL]) of patients with consecutive solid cancer treated with ICIs, and we investigated their role in predicting clinical outcomes.

RESULTS

At a median follow-up of 32.9 months, among 430 enrolled patients, those with TC ≥ 200 mg/dl showed longer median progression-free survival (mPFS; 6.6 vs. 4.7 months, P = .4), although not reaching statistical significance, and significantly longer median overall survival (mOS; 19.4 vs. 10.8 months, P = .02) compared to those with TC < 200 mg/dl. Conversely, patients with TG ≥150 mg/dl displayed shorter PFS (3.4 vs. 5.1 months, P = .02) and OS (7.1 vs. 12.9 months, P = .009) compared to those with TG <150 mg/dl. TC and TG were then combined in a "LIPID score" identifying three subgroups: good-risk (GR) (TC ≥200 mg/dl and TG <150 mg/dl), intermediate-risk (IR) (TC <200 mg/dl and TG <150 mg/dl or TC ≥200 mg/dl and TG ≥150 mg/dl) and poor-risk (PR) (TC <200 mg/dl and TG ≥150 mg/dl). The mPFS of GR, IR, and PR groups was 7.8, 4.3, and 2.5 months, respectively (P = .005); mOS of GR, IR, and PR was 20.4, 12.4, and 5.3 months, respectively (P < .001). At multivariable analysis, the PR profile represented an independent poor prognostic factor for both PFS and OS.

CONCLUSIONS

We developed a lipid score that defined subgroups of patients with cancer who differently benefit from ICIs. Further mechanistic insights are warranted to clarify the prognostic and predictive role of lipid profile components in patients treated with ICIs.

Statin therapy: a potential adjuvant to immunotherapies in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide and accounts for more than 90% of primary liver cancer. The advent of immune checkpoint inhibitor (ICI)-related therapies combined with angiogenesis inhibition has revolutionized the treatment of HCC in late-stage and unresectable HCC, as ICIs alone were disappointing in treating HCC. In addition to the altered immune microenvironment, abnormal lipid metabolism in the liver has been extensively characterized in various types of HCC. Stains are known for their cholesterol-lowering properties and their long history of treating hypercholesterolemia and reducing cardiovascular disease risk. Apart from ICI and other conventional therapies, statins are frequently used by advanced HCC patients with dyslipidemia, which is often marked by the abnormal accumulation of cholesterol and fatty acids in the liver. Supported by a body of preclinical and clinical studies, statins may unexpectedly enhance the efficacy of ICI therapy in HCC patients through the regulation of inflammatory responses and the immune microenvironment. This review discusses the abnormal changes in lipid metabolism in HCC, summarizes the clinical evidence and benefits of stain use in HCC, and prospects the possible mechanistic actions of statins in transforming the immune microenvironment in HCC when combined with immunotherapies. Consequently, the use of statin therapy may emerge as a novel and valuable adjuvant for immunotherapies in HCC.