Zotarolimus for the treatment of coronary artery disease: pathophysiology, DES design, clinical evaluation and future perspective

The role of the methoxy group in approved drugs

The methoxy substituent is prevalent in natural products and, consequently, is present in many natural product-derived drugs. It has also been installed in modern drug molecules with no remnant of natural product features because medicinal chemists have been taking advantage of the benefits that this small functional group can bestow on ligand-target binding, physicochemical properties, and ADME parameters. Herein, over 230 methoxy-containing small-molecule drugs, as well as several fluoromethoxy-containing drugs, are presented from the vantage point of the methoxy group. Biochemical mechanisms of action, medicinal chemistry SAR studies, and numerous X-ray cocrystal structures are analyzed to identify the precise role of the methoxy group for many of the drugs and drug classes. Although the methoxy substituent can be considered as the hybridization of a hydroxy and a methyl group, the combination of these functionalities often results in unique effects that can amount to more than the sum of the individual parts.

A Review of the Ultrathin Orsiro Biodegradable Polymer Drug-eluting Stent in the Treatment of Coronary Artery Disease

Drug-eluting stents (DES) have revolutionised the treatment of coronary artery disease (CAD) in patients undergoing percutaneous coronary intervention. In recent years, there has been a focus on a new generation of DES, such as biodegradable polymer DES (BP-DES). This novel stent platform was developed with the hope of eliminating the risk of very late stent thrombosis associated with the current gold-standard durable polymer DES (DP-DES). Ultrathin Orsiro BP-DES (Biotronik, Bülach, Switzerland) are based on a cobalt-chromium stent platform that is coated with a bioresorbable polymer coating containing sirolimus. These devices have one of the thinnest struts available in the current market and have the theoretical benefit of reducing a chronic inflammatory response in the vessel wall. In 2019, the United States Food and Drug Administration (FDA) approved the use of Orsiro BP-DES in patients with CAD based on promising results in recent landmark trials, such as BIOFLOW V and BIOSTEMI. The aim of the present review article was to discuss the history of stent technology and the continued opportunities for improvements, focusing on the potential benefits of Orsiro BP-DES.

Advances in stent technologies and their effect on clinical efficacy and safety

The introduction of intracoronary stents represented a major advance in interventional cardiology. While bare metal stents set the benchmark for improved safety over angioplasty, intimal hyperplasia and subsequent restenosis were important limitations. First-generation drug-eluting stents demonstrated significant improvements in efficacy, but not necessarily safety, and further technologic developments have focused on optimizing both. Current advances and understanding in stent design continue to improve on these concepts. This review summarizes past and present technology with particular emphasis on the principles underlying the efficacy and safety of drug-eluting stents, and offers a glimpse into the next generations of stents aimed at treating symptomatic coronary artery disease.

Learning from the Cardiologists and Developing Eluting Stents Targeting the Mtor Pathway for Pulmonary Application; A Future Concept for Tracheal Stenosis

Tracheal stenosis due to either benign or malignant disease is a situation that the pulmonary physicians and thoracic surgeons have to cope in their everyday clinical practice. In the case where tracheal stenosis is caused due to malignancy mini-interventional interventions with laser, apc, cryoprobe, balloon dilation or with combination of more than one equipment and technique can be used. On the other hand, in the case of a benign disease such as; tracheomalacia the clinician can immediately upon diagnosis proceed to the stent placement. In both situations however; it has been observed that the stents induce formation of granuloma tissue in both or one end of the stent. Therefore a frequent evaluation of the patient is necessary, taking also into account the nature of the primary disease. Evaluation methodologies identifying different types and extent of the trachea stenosis have been previously published. However; we still do not have an effective adjuvant therapy to prevent granuloma tissue formation or prolong already treated granuloma lesions. There have been proposed many mechanisms which induce the abnormal growth of the local tissue, such as; local pressure, local stress, inflammation and vascular endothelial growth factor overexpression. Immunomodulatory agents inhibiting the mTOR pathway are capable of inhibiting the inflammatory cascade locally. In the current mini-review we will try to present the current knowledge of drug eluting stents inhibiting the mTOR pathway and propose a future application of these stents as a local anti-proliferative treatment.

Location-dependent coronary artery diffusive and convective mass transport properties of a lipophilic drug surrogate measured using nonlinear microscopy

PURPOSE

Arterial wall mass transport properties dictate local distribution of biomolecules or locally delivered dugs. Knowing how these properties vary between coronary artery locations could provide insight into how therapy efficacy is altered between arterial locations.

METHODS

We introduced an indocarbocyanine drug surrogate to the lumens of left anterior descending and right coronary (LADC; RC) arteries from pigs with or without a pressure gradient. Interstitial fluorescent intensity was measured on live samples with multiphoton microscopy. We also measured binding to porcine coronary SMCs in monoculture.

RESULTS

Diffusive transport constants peaked in the middle sections of the LADC and RC arteries by 2.09 and 2.04 times, respectively, compared to the proximal and distal segments. There was no statistical difference between the average diffusivity value between LADC and RC arteries. The convection coefficients had an upward trend down each artery, with the RC being higher than the LADC by 3.89 times.

CONCLUSIONS

This study demonstrates that the convective and diffusive transport of lipophilic molecules changes between the LADC and the RC arteries as well as along their length. These results may have important implications in optimizing drug delivery for the treatment of coronary artery disease.

Zotarolimus-eluting stent versus sirolimus-eluting and paclitaxel-eluting stents for percutaneous coronary intervention: a meta-analysis of randomized trials

BACKGROUND

The zotarolimus-eluting stent (ZES) is a new drug-eluting stent that delivers zotarolimus, a synthetic analogue of sirolimus, through a biocompatible phosphorylcholine polymer coating. ZES has shown promising results compared with bare-metal stents, but its safety and efficacy against sirolimus-eluting (SES) and paclitaxel-eluting (PES) stents is yet to be established.

AIMS

We aimed to summarize current evidence from randomized trials comparing ZES with SES and PES.

METHODS

We searched the Medline, Embase and CENTRAL databases for randomized studies comparing ZES with SES and PES for percutaneous coronary intervention. Relevant clinical and angiographic outcomes were extracted and combined using random and fixed-effect models for heterogeneous and homogenous outcomes, respectively.

RESULTS

Seven randomized trials met the inclusion criteria: ZES group, n=3787; SES group, n=2606; PES group, n=1966. Compared with SES, ZES was associated with significantly higher odds of clinically driven target vessel revascularization (odds ratio [OR] 2.36, 95% confidence interval [CI] 1.78-3.14) and target lesion revascularization (OR 2.46, 95% CI 1.36-4.46). Compared with SES, ZES had higher in-stent restenosis (OR 6.13, 95% CI 3.96-9.50), late lumen loss 'in-stent' (mean difference [MD] 0.39 mm, 95% CI 0.34-0.44) and late lumen loss 'in-segment' (MD 0.18 mm, 95% CI 0.15-0.21). ZES was associated with higher in-stent late lumen loss than PES (MD 0.18 mm, 95% CI 0.07-0.28). There were no differences in mortality, reinfarction or stent thrombosis with ZES compared with SES and PES.

CONCLUSION

ZES is not superior to PES and is inferior to SES in terms of angiographic outcomes and clinically driven revascularization.

Efficacy and safety of zotarolimus-eluting stents compared with sirolimus-eluting stents in patients undergoing percutaneous coronary interventions--a meta-analysis of randomized controlled trials

BACKGROUND

Whether ZES can further improve angiographic and clinical outcomes compared to SES still remains uncertain.

OBJECTIVES

The aim of this study was to assess the efficacy and safety of zotarolimus-eluting stents (ZES) compared with sirolimus-eluting stents (SES) in patients undergoing percutaneous coronary interventions (PCI).

METHODS

Major electronic information sources were explored for randomized controlled trials comparing ZES with SES among patients undergoing PCI during at least 9 months follow-up. The primary efficacy outcomes were target lesion revascularization (TLR), target vessel revascularization (TVR), and major adverse cardiac events (MACE); safety outcomes were stent thrombosis (ST), myocardial infarction (MI), and cardiac death.

RESULTS

Seven comparative studies were identified (a total of 5983 patients). When compared with ZES at 12-month follow-up, SES significantly reduced risk of MACE (relative risk [RR]: 0.74, 95% confidence interval [CI]: 0.61 to 0.89, p=0.002), and TLR (RR:0.39; 95% CI: 0.29 to 0.52; p<0.00001), without significant differences in terms of TVR (RR:0.68, 95% CI: 0.38 to 1.20; p=0.18), ST (RR:0.71; 95% CI: 0.39 to 1.31; p=0.28), cardiac death (RR:0.83; 95% CI: 0.49-1.42, p=0.50) or MI (RR:1.08; 95%CI: 0.80 to 1.45; p=0.62).

CONCLUSIONS

At 12-month follow-up, SES are superior to ZES in reducing the incidences of TLR and MACE in patients undergoing PCI, without significant differences in terms of TVR, ST, cardiac death, and MI.

Vascular response to zotarolimus-coated balloons in injured superficial femoral arteries of the familial hypercholesterolemic Swine

BACKGROUND

Drug-coated balloons are rapidly emerging as a therapeutic alternative for the interventional treatment of peripheral vascular disease. The purpose of this study was to test the hypothesis that an angioplasty balloon coated with the mTOR inhibitor zotarolimus (ZCB) would inhibit neointimal hyperplasia in a novel injury-based superficial femoral artery model in the familial hypercholesterolemic swine.

METHODS AND RESULTS

A total of 44 familial hypercholesterolemic swine were included (12 designated to study tissue pharmacokinetics and 32 to study safety and efficacy). Fogarty balloon denudation was performed in all superficial femoral artery segments, followed by balloon angioplasty. In the pharmacokinetic study, a total of 24 ZCBs (300 μg/cm(2)) were used. Zotarolimus was detected in arterial tissue at 5 minutes (162 ng/mg of tissue), 24 hours (5.9 ng/mg of tissue), and 28 days (0.007 ng/mg of tissue) after ZCB inflation. In the safety and efficacy study, superficial femoral artery segments were randomized to either high-dose (600 μg/cm(2), n=16), low-dose (300 μg/cm(2), n=16), or paired uncoated balloons (high-dose ZCB control, n=16; low-dose ZCB control, n=16). At 28 days, the percentage of angiographic stenosis was similar among all tested groups. Histological analysis demonstrated a reduction in neointimal formation in both ZCB groups compared with controls (high-dose ZCB 44% reduction, P=0.007; low-dose ZCB 22% reduction, P=0.08). There was no evidence of delayed arterial healing or vascular toxicity in any of the ZCB groups.

CONCLUSIONS

The single delivery of zotarolimus via coated balloon is feasible, and therapeutic levels are maintained up to 28 days. The ZCB technology appears to be effective in the reduction of neointimal proliferation in the superficial femoral artery of the familial hypercholesterolemic swine.

Late safety, efficacy, and cost-effectiveness of a zotarolimus-eluting stent compared with a paclitaxel-eluting stent in patients with de novo coronary lesions: 2-year follow-up from the ENDEAVOR IV trial (Randomized, Controlled Trial of the Medtronic Endeavor Drug [ABT-578] Eluting Coronary Stent System Versus the Taxus Paclitaxel-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions)

OBJECTIVES

The aim of this study was to assess, after 2 years of follow-up, the safety, efficacy, and cost-effectiveness of a zotarolimus-eluting stent (ZES) compared with a paclitaxel-eluting stent (PES) in patients with native coronary lesions.

BACKGROUND

Early drug-eluting stents were associated with a small but significant incidence of very late stent thrombosis (VLST), occurring >1 year after the index procedure. The ZES has shown encouraging results in clinical trials.

METHODS

The ENDEAVOR IV trial (Randomized, Controlled Trial of the Medtronic Endeavor Drug [ABT-578] Eluting Coronary Stent System Versus the Taxus Paclitaxel-Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions), a randomized (1:1), single-blind, controlled trial (n = 1,548) compared ZES versus PES in patients with single de novo coronary lesions. Two-year follow-up was obtained in 96.0% of ZES and 95.4% of PES patients. The primary end point was target vessel failure (TVF), and safety end points included Academic Research Consortium-defined stent thrombosis. Economic end points analyzed included quality-adjusted survival, medical costs, and relative cost-effectiveness of ZES and PES.

RESULTS

The TVF at 2 years was similar in ZES and PES patients (11.1% vs. 13.1%, p = 0.232). There were fewer myocardial infarctions (MIs) in ZES patients (p = 0.022), due to fewer periprocedural non-Q-wave MIs and fewer late MIs between 1 and 2 years. Late MIs were associated with increased VLST (PES: 6 vs. ZES: 1; p = 0.069). Target lesion revascularization was similar comparing ZES with PES (5.9% vs. 4.6%; p = 0.295), especially in patients without planned angiographic follow-up (5.2% vs. 4.9%; p = 0.896). The cost-effectiveness of ZES and PES was similar.

CONCLUSIONS

After 2 years of follow-up, ZES demonstrated efficacy and cost-effectiveness comparable to PES, with fewer MIs and a trend toward less VLST. (The ENDEAVOR IV Clinical Trial: A Trial of a Coronary Stent System in Coronary Artery Lesions; NCT00217269).

A randomized comparison of the Endeavor zotarolimus-eluting stent versus the TAXUS paclitaxel-eluting stent in de novo native coronary lesions 12-month outcomes from the ENDEAVOR IV trial

OBJECTIVES

The ENDEAVOR IV (Randomized Comparison of Zotarolimus-Eluting and Paclitaxel-Eluting Stents in Patients with Coronary Artery Disease) trial evaluated the safety and efficacy of the zotarolimus-eluting stent (ZES) compared with the paclitaxel-eluting stent (PES).

BACKGROUND

First-generation drug-eluting stents have reduced angiographic and clinical restenosis, but long-term safety remains controversial. A second-generation drug-eluting stent, which delivers zotarolimus, a potent antiproliferative agent, via a biocompatible phosphorylcholine polymer on a cobalt alloy thin-strut stent has shown promising experimental and early clinical results.

METHODS

This is a prospective, randomized (1:1), single-blind, controlled trial comparing outcomes of patients with single de novo coronary lesions treated with ZES or PES. The primary end point was noninferiority of 9-month target vessel failure defined as cardiac death, myocardial infarction, or target vessel revascularization.

RESULTS

Among a total of 1,548 patients assigned to ZES (n = 773) or PES (n = 775), at 9 months, ZES was noninferior to PES with rates of target vessel failure 6.6% versus 7.1%, respectively (p(noninferiority) < or = 0.001). There were fewer periprocedural myocardial infarctions with ZES (0.5% vs. 2.2%; p = 0.007), whereas at 12 months, there were no significant differences between groups in rates of cardiac death, myocardial infarction, target vessel revascularization, or stent thrombosis. Although incidence of 8-month binary angiographic in-segment restenosis was higher in patients treated with ZES versus PES (15.3% vs. 10.4%; p = 0.284), rates of 12-month target lesion revascularization were similar (4.5% vs. 3.2%; p = 0.228), especially in patients without planned angiographic follow-up (3.6% vs. 3.2%; p = 0.756).

CONCLUSIONS

These findings demonstrate that ZES has similar clinical safety and efficacy compared with PES in simple and medium complexity single de novo coronary lesions. (ENDEAVOR IV Clinical Trial; NCT00217269).