An FDA overview of rodent carcinogenicity studies of angiotensin II AT-1 receptor blockers: pulmonary adenomas and carcinomas

Antihypertensive treatment and risk of cancer: an individual participant data meta-analysis

BACKGROUND

Some studies have suggested a link between antihypertensive medication and cancer, but the evidence is so far inconclusive. Thus, we aimed to investigate this association in a large individual patient data meta-analysis of randomised clinical trials.

METHODS

We searched PubMed, MEDLINE, The Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from Jan 1, 1966, to Sept 1, 2019, to identify potentially eligible randomised controlled trials. Eligible studies were randomised controlled trials comparing one blood pressure lowering drug class with a placebo, inactive control, or other blood pressure lowering drug. We also required that trials had at least 1000 participant years of follow-up in each treatment group. Trials without cancer event information were excluded. We requested individual participant data from the authors of eligible trials. We pooled individual participant-level data from eligible trials and assessed the effects of angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), β blockers, calcium channel blockers, and thiazide diuretics on cancer risk in one-stage individual participant data and network meta-analyses. Cause-specific fixed-effects Cox regression models, stratified by trial, were used to calculate hazard ratios (HRs). The primary outcome was any cancer event, defined as the first occurrence of any cancer diagnosed after randomisation. This study is registered with PROSPERO (CRD42018099283).

FINDINGS

33 trials met the inclusion criteria, and included 260 447 participants with 15 012 cancer events. Median follow-up of included participants was 4·2 years (IQR 3·0-5·0). In the individual participant data meta-analysis comparing each drug class with all other comparators, no associations were identified between any antihypertensive drug class and risk of any cancer (HR 0·99 [95% CI 0·95-1·04] for ACEIs; 0·96 [0·92-1·01] for ARBs; 0·98 [0·89-1·07] for β blockers; 1·01 [0·95-1·07] for thiazides), with the exception of calcium channel blockers (1·06 [1·01-1·11]). In the network meta-analysis comparing drug classes against placebo, we found no excess cancer risk with any drug class (HR 1·00 [95% CI 0·93-1·09] for ACEIs; 0·99 [0·92-1·06] for ARBs; 0·99 [0·89-1·11] for β blockers; 1·04 [0·96-1·13] for calcium channel blockers; 1·00 [0·90-1·10] for thiazides).

INTERPRETATION

We found no consistent evidence that antihypertensive medication use had any effect on cancer risk. Although such findings are reassuring, evidence for some comparisons was insufficient to entirely rule out excess risk, in particular for calcium channel blockers.

FUNDING

British Heart Foundation, National Institute for Health Research, Oxford Martin School.

Systematic review and meta-analysis of randomised controlled clinical trial evidence refutes relationship between pharmacotherapy with angiotensin-receptor blockers and an increased risk of cancer

AIMS

The potential influence of angiotensin-receptor blockers (ARBs) on carcinogenesis is a much-debated topic. Both observational, as well as preclinical studies in rodent carcinogenic assays, suggest a major role of the Renin-Angiotensin-Aldosterone-System (RAAS) in cancer development. Therefore, a systematic review and meta-analysis with available study data on ARBs and carcinogenicity in general as primary outcome were conducted. Secondary outcomes were defined as tumour-specific mortality rates and the frequency of new cases of specific tumour types with particular emphasis on lung, breast, and prostate cancer.

METHODS

A systematic literature research was performed in MEDLINE, EMBASE, Cochrane Library, and TOXLINE. We used a combination of MeSH terms, keywords and substance names of ARBs and searched between 1950 and 2016. At least 100 participants in each study arm and a minimum follow-up for one year were necessary for study inclusion. Odds ratios (OR) were calculated by a random-effects model.

RESULTS

A total of 8818 potentially eligible publications were identified of whom seven randomised controlled trials, four case-control studies and one cohort study met our inclusion criteria. As a key result, we found no effect on carcinogenesis in randomised controlled trials for ARB usage. (OR 1.02, 95% CI 0.87-1.19; p = .803). Conflicting results with observational studies could be explained by poor reporting- and study qualities.

CONCLUSIONS

The results of our meta-analysis focusing only on high evidence levels and study designs (RCTs) did not reveal any relationship between pharmacotherapy with an ARB and an increased risk for cancer in general.

Targeting the renin-angiotensin system to improve cancer treatment: Implications for immunotherapy

Renin-angiotensin system (RAS) inhibitors (RASi)-widely prescribed for the treatment of cardiovascular diseases-have considerable potential in oncology. The RAS plays a crucial role in cancer biology and affects tumor growth and dissemination directly and indirectly by remodeling the tumor microenvironment. We review clinical data on the benefit of RASi in primary and metastatic tumors and propose that, by activating immunostimulatory pathways, these inhibitors can enhance immunotherapy of cancer.

Alterations in Gene Expression of Components of the Renin-Angiotensin System and Its Related Enzymes in Lung Cancer

Objectives

The study assessed the existence and significance of associations between the expression of fifteen renin-angiotensin system component genes and lung adenocarcinoma.

Materials and Methods

NCBI's built-in statistical tool, GEO2R, was used to calculate Student's t-tests for the associations found in a DNA expression study of adenocarcinoma and matched healthy lung tissue samples. The raw data was processed with GeneSpring™ and then used to generate figures with and without Sidak's multiple comparison correction.

Results

Ten genes were found to be significantly associated with adenocarcinoma. Seven of these associations remained statistically significant after correction for multiple comparisons. Notably, AGTR2, which encodes the AT₂ angiotensin II receptor subtype, was significantly underexpressed in adenocarcinoma tissue (p < 0.01). AGTR1, ACE, ENPEP, MME, and PRCP, which encode the AT₁ angiotensin II receptor, angiotensin-converting enzyme, aminopeptidase N, neprilysin, and prolylcarboxypeptidase, respectively, were also underexpressed. AGT, which encodes angiotensinogen, the angiotensin peptide precursor, was overexpressed in adenocarcinoma tissue.

Conclusion

The results suggest an association between the expression of the genes for renin-angiotensin system-related proteins and adenocarcinoma. While further research is necessary to conclusively demonstrate a link between the renin-angiotensin system and lung cancers, the results suggest that the renin-angiotensin system plays a role in the pathology of adenocarcinoma.

The Comparative Effectiveness of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers in Patients With Diabetes

The evidence examining the effect of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) on mortality in high-risk patients is conflicting. To further examine this controversy, the authors compared outcomes between ACE inhibitors and ARBs in a large clinical diabetes registry. A retrospective cohort of 87,472 incident users followed for 105,702 patient-years was analyzed. Average age was 53.1±10.1 years, 54.2% were men, and 14.4% had cardiovascular disease. All-cause hospitalization or all-cause mortality, the composite primary endpoint, occurred in 10,943 (12.5%) patients. Compared with ACE inhibitors, the adjusted hazard for ARBs was 0.90 (95% confidence interval, 0.87-0.94) for all-cause hospitalization or mortality; 0.95 (0.65-1.40) for mortality; 0.90 (0.87-0.94) for all-cause hospitalization; and 0.81 (0.74-0.89) for cardiovascular admission. ARB use was associated with a reduced, not increased, risk of hospitalization/mortality relative to ACE inhibition. This was driven by lower hospitalization, with a null mortality result.

Renin-angiotensin system blockade: Its contribution and controversy

Angiotensin II is a key biological peptide in the renin-angiotensin system that regulates blood pressure and renal hemodynamics, and extensive experimental studies have shown that angiotensin II promotes diverse fibrotic changes and induces neovascularization in several inflammatory diseases. It is known that angiotensin II can be controlled using renin-angiotensin system blockade when angiotensin II is the main factor inducing a particular disease, and renin-angiotensin system blockade has assumed a central role in the treatment of inflammatory nephritis, cardiovascular disorders and retinopathy. In contrast, renin-angiotensin system blockade was found to have not only these effects but also other functions, such as inhibition of cancer growth, angiogenesis and metastasis. Numerous studies have sought to elucidate the mechanisms and support these antitumor effects. However, a recent meta-analysis showed that renin-angiotensin system blockade use might in fact increase the incidence of cancer, so renin-angiotensin system blockade use has become somewhat controversial. Although the renin-angiotensin system has most certainly made great contributions to experimental models and clinical practice, some issues still need to be resolved. The present review discusses the contribution and controversy surrounding the renin-angiotensin system up to the present time.

[Oncology-related issues of angiotensin-receptor blockers]

Recently controversial data emerged regarding the cancer inducing activity of angiotensin-receptor blockers. There may be several reasons which may explain the controversial data published in the scientific literature including wrong trial design or misinterpretation of data. Considering the large number of patients receiving treatment for hypertension, it is essential to have a clear view of the cancer-related safety of these drugs. This paper tries to give an overview on this issue based on data available in the literature. According to our present knowledge, angiotensin-receptor blockers exert more likely anticancer activity rather than carcinogenesis inducing effect. In fact, some oncologic trials point to this direction, because angiotensin-receptor blockers are suggested as co-treatment to chemotherapy in cases of pancreatic, oesophageal and gastric cancers.