Local delivery of paclitaxel in the treatment of peripheral arterial disease

Robustness of Longitudinal Safety and Efficacy After Paclitaxel-Based Endovascular Therapy for Treatment of Femoro-Popliteal Artery Occlusive Disease: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The aims of this study were: i) to assess fragility indices (FIs) of individual randomized controlled trials (RCTs) that compared paclitaxel-based drug-coated balloons (DCBs) or drug-eluting stents (DESs) versus standard endovascular devices, and ii) to meta-analyze mid-term and long-term safety and efficacy outcomes from available RCT data while also estimating the FI of pooled results.

METHODS

This systematic review has been registered in the PROSPERO public database (CRD42022304326 http://www.crd.york.ac.uk/PROSPERO). A query of PubMed (Medline), EMBASE (Excerpta Medical Database), Scopus, and CENTRAL (Cochrane Central Register of Controlled Trials) databases was performed to identify eligible RCTs. Rates of primary patency (PP) and target lesion revascularization (TLR) were assessed as efficacy outcomes, while lower limb amputation (LLA) consisting of major amputation that is. below or above the knee and all-cause mortality were estimated as safety outcomes. All outcomes were pooled with a random effects model to account for any clinical and study design heterogeneity. The analyses were performed by dividing the RCTs according to their maximal follow-up length (mid-term was defined as results up to 2-3 years, while long-term was defined as results up to 4-5 years). For each individual outcome, the FI and reverse fragility index (RFI) were calculated according to whether the outcome results were statistically significant or not, respectively. The fragility quotient (FQ) and reverse fragility quotient (RFQ), which are the FI or RFI divided by the sample size, were also calculated.

RESULTS

A total of 2,337 patients were included in the systematic review and meta-analysis. There were 2 RCTs examining DES devices and 14 RCTs evaluating different DCBs. For efficacy outcomes, there was evidence that paclitaxel-based endovascular therapy increased the PP rate and reduced the TLR rate at mid-term, with a calculated pooled risk ratio (RR) of 1.66 for patency (95% CI, 1.55-1.86; P < 0.001), with a corresponding number needed-to-treat (NNT) of 3 patients (95% CI, 2.9-3.8) and RR of 0.44 for TLR (95% CI, 0.35-0.54; P = 0.027), respectively. Similarly, there was evidence that paclitaxel-based endovascular therapy both increased PP and decreased TLR rates at long-term, with calculated pooled RR values of 1.73 (95% CI, 1.12-2.61; P = 0.004) and 0.53 (95% CI, 0.45-0.62; P = 0.82), respectively. For safety outcomes, there was evidence that paclitaxel-based endovascular therapy increased all-cause mortality at mid-term, with a calculated pooled RR of 2.05 (95% CI, 1.21-3.24). However, there was no difference between treatment arms in LLA at mid-term (95% CI, 0.1-2.7; P = 0.68). Similarly, neither all-cause mortality nor LLA at long-term differed between treatment arms, with a calculated pooled RR of 0.66, 1.02 (95% CI, 0.31-3.42) and 1.02 (95% CI, 0.30-5.21; P = 0.22), respectively. The pooled estimates of PP at mid-term were robust (FI = 28 and FQ = 1.9%) as were pooled rates of TLR (FI = 18 and FQ = 0.9%). However, when safety outcomes were analyzed, the robustness of the meta-analysis decreased significantly. In fact, the relationship between the use of paclitaxel-coated devices and all-cause mortality at mid-term showed very low robustness (FI = 4 and FQ = 0.2%). At 5 years, only the benefit of paclitaxel-based devices to reduce TLR remained robust, with an FI of 32 and an FQ of 3.1%.

CONCLUSIONS

The data supporting clinical efficacy endpoints of RCTs that examined paclitaxel-based devices in the treatment of femoral-popliteal arterial occlusive disease were robust; however, the pooled safety endpoints were highly fragile and prone to bias due to loss of patient follow-up in the original studies. These findings should be considered in the ongoing debate concerning the safety of paclitaxel-based devices.

Mortality, Safety, and Effectiveness of Paclitaxel-Containing Balloons and Stents in the Femoropopliteal Artery: Systematic Review and Meta-Analysis of Randomized Controlled Trials since 2018

PURPOSE

To provide an updated systematic review and meta-analysis of safety and effectiveness outcomes with paclitaxel-containing devices.

MATERIALS AND METHODS

A systematic review and meta-analysis of randomized controlled trials (RCTs) investigating paclitaxel-containing balloons or stents in the treatment of femoropopliteal disease was performed. Pooled risk ratio (RR) was calculated using the inverse-variance, random-effects model in the assessment of primary patency, all-cause mortality, target limb major amputation, target lesion revascularization (TLR), and thrombosis.

RESULTS

In total, 19 RCTs were included comprising 4,284 participants. All-cause mortality rates did not differ significantly between the 2 arms at 12 months (RR, 1.06; 95% confidence interval [CI], 0.66-1.72; P = .80), 24 months (RR, 0.92; 95% CI, 0.56-1.50; P = .73), 36 months (RR, 1.21; 95% CI, 0.65-2.25; P = .55), or 48-60 months (RR, 0.95; 95% CI, 0.66-1.39; P = .81) after intervention. Primary patency was significantly higher at 12 months in the paclitaxel-containing arm: 80.92% (1,438/1,777) versus 57.48% (607/1,056) in the control arm (RR, 1.44; 95% CI, 1.30-1.59; P < .00001).

CONCLUSIONS

The present study demonstrates no statistically significant difference in all-cause mortality, target limb major amputation, or thrombosis with paclitaxel drug-eluting therapy to the femoropopliteal region. Additionally, improved and durable patency rates with a statistically significantly lower risk of clinically driven TLR with paclitaxel drug-eluting therapy have been demonstrated.

Data sources and applied methods for paclitaxel safety signal discernment

Background

Following the identification of a late mortality signal, the Food and Drug Administration (FDA) convened an advisory panel that concluded that additional clinical study data are needed to comprehensively evaluate the late mortality signal observed with the use of drug-coated balloons (DCB) and drug-eluting stent (DES). The objective of this review is to (1) identify and summarize the existing clinical and cohort studies assessing paclitaxel-coated DCBs and DESs, (2) describe and determine the quality of the available data sources for the evaluation of these devices, and (3) present methodologies that can be leveraged for proper signal discernment within available data sources.

Methods

Studies and data sources were identified through comprehensive searches. original research studies, clinical trials, comparative studies, multicenter studies, and observational cohort studies written in the English language and published from January 2007 to November 2021, with a follow-up longer than 36 months, were included in the review. Data quality of available data sources identified was assessed in three groupings. Moreover, accepted data-driven methodologies that may help circumvent the limitations of the extracted studies and data sources were extracted and described.

Results

There were 39 studies and data sources identified. This included 19 randomized clinical trials, nine single-arm studies, eight registries, three administrative claims, and electronic health records. Methodologies focusing on the use of existing premarket clinical data, the incorporation of all contributed patient time, the use of aggregated data, approaches for individual-level data, machine learning and artificial intelligence approaches, Bayesian approaches, and the combination of various datasets were summarized.

Conclusion

Despite the multitude of available studies over the course of eleven years following the first clinical trial, the FDA-convened advisory panel found them insufficient for comprehensively assessing the late-mortality signal. High-quality data sources with the capabilities of employing advanced statistical methodologies are needed to detect potential safety signals in a timely manner and allow regulatory bodies to act quickly when a safety signal is detected.

Drug-Coated Balloon Venoplasty to Treat Iatrogenic Pulmonary Vein Stenosis

Pulmonary vein stenosis (PVS) is a condition that has seen a decrease in incidence in recent years. Whereas balloon angioplasty and stenting are both acceptable treatment options for PVS, they are limited by the high rate of restenosis. This research paper presents 4 cases of severe symptomatic PVS that were successfully treated with the use of drug-coated balloons, resulting in positive outcomes. (Level of Difficulty: Advanced.).

Biosynthetic Plastics as Tunable Elastic and Visible Stent with Shape-Memory to Treat Biliary Stricture

Common biliary tract is ≈4 mm in diameter to deliver bile from liver to small intestine to help digestion. The abnormal narrowing leads to severe symptoms such as pain and nausea. Stents are an effective treatment. Compared with non-degradable stents which require repeated removal, biodegradable stents have the advantage of reducing secondary injury related to endoscopic operation and patient burden. However, current biodegradable materials may cause tissue hyperplasia and the treatment method does not target etiology of stricture. So recurrence rates after biodegradable stent implantation are still high. Here, a biodegradable helical stent fabricated from biosynthetic P(3HB-co-4HB) is reported. Tunable properties can be acquired through altering culture substrates. Stent shows shape memory in various solvents. The stent has an optimized design with helical structure and outer track. The self-expanding of helical structure and double drainage realized by outer track greatly improve drainage of bile. Importantly, stent-loading triamcinolone acetonide can inhibit proliferation of fibroblasts and reduce incidence of restricture. Therapeutic effect is also demonstrated in minipigs with biliary stricture. The results of minipig experiments show that biliary duct in treatment group is unobstructed and tissue hyperplasia is effectively inhibited.

Research progress on the therapeutic effects of nanoparticles loaded with drugs against atherosclerosis

Presently, there are many drugs for the treatment of atherosclerosis (AS), among which lipid-lowering, anti-inflammatory, and antiproliferative drugs have been the most studied. These drugs have been shown to have inhibitory effects on the development of AS. Nanoparticles are suitable for AS treatment research due to their fine-tunable and modifiable properties. Compared with drug monotherapy, experimental results have proven that the effects of nanoparticle-encapsulated drugs are significantly enhanced. In addition to nanoparticles containing a single drug, there have been many studies on collaborative drug treatment, collaborative physical treatment (ultrasound, near-infrared lasers, and external magnetic field), and the integration of diagnosis and treatment. This review provides an introduction to the therapeutic effects of nanoparticles loaded with drugs to treat AS and summarizes their advantages, including increased targeting ability, sustained drug release, improved bioavailability, reduced toxicity, and inhibition of plaque and vascular stenosis.

Meta-Analysis Comparing Drug-Coated Balloons and Percutaneous Transluminal Angioplasty for Infrapopliteal Artery Disease

Limited data is available regarding the safety and effectiveness of drug-coated balloon (DCB) versus conventional percutaneous transluminal balloon angioplasty (PTA) in the treatment of critical limb ischemia because of infrapopliteal peripheral arterial disease. We conducted an updated meta-analysis to assess the safety and efficacy of DCB in the treatment of infrapopliteal disease. A database search of PubMed/MEDLINE, EMBASE, and the Cochrane Library was performed by 2 reviewers from inception through November 15, 2021. Randomized trials that compared DCB with conventional PTA in treating infrapopliteal arterial disease were included. The risk ratios (RRs) and 95% confidence intervals (CIs) were reported. A total of 9 trials were included (1,501 participants) in the study. The mean age was 71.1 ± 10.2 years. Regarding the primary end points, treating infrapopliteal arterial disease with DCB had a lower incidence of re-stenosis (RR 0.48, 95% CI 0.33 to 0.70, p = 0.0001) with no significant difference in all-cause mortality (RR 1.11, 95% CI 0.73 to 1.69, p = 0.61), compared with conventional PTA. With regards to the secondary end points, DCB usage was associated with a significant reduction in clinically driven target lesion revascularization (RR 0.54, 95% CI 0.35 to 0.84, p = 0.006) with no significant difference with regards to major target limb amputation and major adverse cardiovascular events (p ≥0.05). In conclusion, among patients with critical limb ischemia secondary to infrapopliteal artery disease, DCB usage was associated with a significantly lower number of restenosis and clinically driven target lesion revascularization compared with conventional PTA. There was no increase in all-cause mortality or major target limb amputation with the use of DCB.

Novelty in the development of biodegradable polymer coatings for biomedical devices: paclitaxel grafting on PDMMLA derivatives

Biocompatible and biodegradable polymers are widely used in the medical field. In some cases, the biopolymer is accompanied by an active drug, which is delivered locally in a controlled manner in order to improve the healing conditions. Poly([R,S]-3,3-dimethylmalic acid) (PDMMLA) is a synthetic amphiphilic biodegradable polymer, which unlike PLA, can be chemically modified to adapt hydrophilic/hydrophobic balance, degradation kinetics, and physicochemical and biological properties. It may contain a lateral alkyl group or a functional group for coupling bioactive molecules to release during its degradation. In this work, we realized the chemical grafting of paclitaxel (PTX), a microtubule stabilizing anti-cancer agent on PDMMLA derivatives bio-polyesters following a Steglich esterification protocol. 1D and 2D NMR analyses validated the reaction with 10% (using 0.1 equivalent) of PTX on the copolymer PDMMLAH₄₀-co-Hex₆₀ (PDMMLA 40/60) and a maximal PTX grafting rate of 55% on the homopolymer PDMMLAH (PDMMLA 100/0). In vitro adhesion and cytotoxicity assays were carried out on HUVEC cells with PDMMLA 40/60, PDMMLA-PTX 30/10/60 and PLA.

Rationale and design of a randomized study comparing the agent drug coated balloon to plain old balloon angioplasty in patients with In-stent restenosis

BACKGROUND

Drug-coated balloon (DCB) technology was developed as an alternative treatment for obstructive coronary artery disease (CAD) and in-stent restenosis (ISR). Management of coronary ISR is clinically challenging and frequently encountered in practice. The Agent DCB uses an inactive excipient to effectively deliver a targeted, therapeutic dose of paclitaxel to the vessel wall.

STUDY DESIGN

AGENT IDE is a prospective, multicenter, randomized controlled trial to evaluate superiority of the Agent DCB to balloon angioplasty in treating patients with ISR. A total of 480 patients with ISR of a previously treated lesion length <26 mm and reference vessel diameter >2.0 mm to ≤4.0 mm will be initially randomized. Subjects presenting with recent myocardial infarction (MI), complex lesions, or thrombus in the target vessel will be excluded. An adaptive group sequential design with one formal interim analysis for sample size re-estimation will be conducted, and the sample size may be increased to a maximum of 600 subjects. The primary endpoint is the rate of 12-month target lesion failure (TLF; composite of any ischemia-driven revascularization of the target lesion (TLR), target vessel related MI, or cardiac death) and will be tested for superiority in the test arm against the control. Functional status and general health-related quality of life will be measured by changes in the EQ-5D scores. Subjects will be followed for 5 years following the index procedure.

CONCLUSION

This study will prospectively evaluate the safety and efficacy of Agent DCB in patients treated for coronary ISR.

Comprehensive Assessment of Current Management Strategies for Patients With Diabetes and Chronic Limb-Threatening Ischemia

Chronic limb-threatening ischemia (CLTI) is the most severe form of peripheral artery disease. It is estimated that 60% of all nontraumatic lower-extremity amputations performed annually in the United States are in patients with diabetes and CLTI. The consequences of this condition are extraordinary, with substantial patient morbidity and mortality and high socioeconomic costs. Strategies that optimize the success of arterial revascularization in this unique patient population can have a substantial public health impact and improve patient outcomes. This article provides an up-to-date comprehensive assessment of management strategies for patients afflicted by both diabetes and CLTI.

Characteristics of atherosclerosis in femoropopliteal artery and its clinical relevance

Atherosclerosis is a systemic disease with different faces. Despite identical or similar pathogenetic mechanisms, atherosclerotic lesions and their clinical manifestations vary in different parts of the vascular system. Peripheral arterial disease (PAD) represents one of the most frequent clinical manifestations of atherosclerosis with predominant location in the superficial femoral artery (SFA). Morphological characteristics of atherosclerotic plaques in peripheral arteries differ from lesions in the coronary and carotid arteries. Plaques in SFA have more fibrotic components, less lipids and inflammatory cells, which makes them more stable and less prone to rupture. Factors that determine the different structure of plaques in SFA compared to coronary arteries include hemodynamic forces, vasa vasorum and calcification. Low shear stress in SFA in the adductor canal is one of the factors which determines frequent atherosclerotic lesions in this region. Lower lipid content and fewer inflammatory cells explain higher stability of SFA plaques. The specific structure of SFA plaques may require preventive and therapeutic measures, which to some extent differ from prevention of coronary atherosclerosis and may include inhibition of fibrotic proliferation in SFA plaques and calcification. Revascularization of PAD differs from procedures used in coronary arteries and requires specific technical expertise and devices.

Mortality is not associated with paclitaxel-coated devices usage in peripheral arterial disease of lower extremities

A recent meta-analysis addressed increased risk of death following revascularization with paclitaxel-coated devices in femopopliteal artery. We evaluated differences in all-cause mortality and amputation free survival between peripheral arterial disease (PAD) patients who were treated with paclitaxel-coated devices and non-paclitaxel-coated devices. This was retrospective population-based cohort study from the National Health Insurance Service claims in South Korea from 2015 to 2019. Multivariate Cox regression analyses after propensity score matching were applied to identify all-cause mortality and amputation-free survival. After propensity score matching, there were 6090 patients per group. The median follow-up days was 580 days (interquartile range [IQR] 240–991 days) and 433 days (IQR 175–757 days) for the non-paclitaxel-coated device group and paclitaxel-coated device group, respectively. Multivariate analysis adjusted for age, sex, diabetes, hypertension, warfarin, and new oral anticoagulants showed that the mortality rate associated with paclitaxel-coated devices was not significantly higher than non-paclitaxel-coated devices (hazard ratio [HR] 0.992; 95% CI 0.91–1.08). The rate of amputation events was higher in patients with paclitaxel-coated devices than those with non-paclitaxel-coated devices (HR 1.614; 95% CI 1.46–1.78). In this analysis, the mortality rate in patients with PAD was not associated with the use of paclitaxel-coated devices, despite a higher amputation rate.

Four-Year Patient-Level Pooled Mortality Analysis of the ILLUMENATE US Pivotal and EU Randomized Controlled Trials

OBJECTIVE

To perform a meta-analysis of two concordant randomized controlled trials (RCTs) examining the long-term, four-year safety profile of the Stellarex drug-coated balloon (DCB) versus percutaneous transluminal angioplasty (PTA) for the treatment of peripheral artery disease.

METHODS

An independent, third-party, meta-analysis of homogenous, patient-level data from the ILLUMENATE Pivotal and ILLUMENATE EU RCTs was performed to assess mortality (time to death) in patients treated for symptomatic femoropopliteal disease. Kaplan Meier (KM) methodology was used to estimate hazard rates of all-cause mortality and Cox proportional hazard modeling was used to assess predictors of mortality. All serious adverse events, including deaths, were adjudicated by an independent, blinded clinical events committee (CEC).

RESULTS

In total, 589 (419 DCB; 170 PTA) patients were included in the pooled analysis of the ILLUMENATE Pivotal and ILLUMENATE EU RCTs. The median follow-up was 1735 days (IQR 1434-1829), equivalent to 4.75 years. Vital status compliance was >95% in each RCT. The total number of deaths through four years was 81/589 (13.8%); 58/419 (13.8%) in the DCB arm and 23/170 (13.5%) in the PTA arm. The one-year KM estimate of all-cause mortality was 1.9% ± 0.7% (estimate ± SE) in those treated with DCB versus 1.2 ± 0.9% in those treated with PTA. At two, three, and four years, the respective KM estimates were 6.6 ± 1.2% versus 4.9 ± 1.7%, 9.3 ± 1.4% versus 9.9 ± 2.4%, and 14.0% ± 1.7% versus 14.4% ± 2.8% (P = 0.864). There were no significant differences in CEC-adjudicated deaths between the two cohorts. In multivariate analysis, predictors of four-year mortality were age (HR, 1.048; 95% CI, 1.026 - 1.071; P < 0.0001), renal insufficiency (HR, 2.440; 95% CI, 1.566 - 3.800; P < 0.0001), and lesion length (HR, 1.004; 95% CI, 1.000 - 1.008; P = 0.041). Neither paclitaxel exposure (DCB versus PTA; HR, 1.086; 95% CI, 0.709 - 1.664; P = 0.705) nor dose (mg; HR, 1.043; 95% CI, 0.971 - 1.119; P = 0.248) were predictors of all-cause mortality at four years.

CONCLUSIONS

This systematic meta-analysis of two concordant ILLUMENATE RCTs shows no difference in all-cause mortality through four-years between Stellarex DCB and PTA, confirming the acceptable, long-term safety profile of the Stellarex DCB.

Paclitaxel Exposure and Dosage of Drug-coated Devices for the Treatment of Femoropopliteal Peripheral Artery Disease

The role of paclitaxel in the treatment of femoropopliteal peripheral arterial disease is currently ambiguous. A summary-level meta-analysis of randomised trials published in 2018 demonstrated that paclitaxel-coated devices were associated with an increased all-cause mortality in those who underwent treatment at 2 years and 5 years. Further evaluation has been undertaken to establish whether there is a specific dose response, mechanism or reproducible signal. At this time, there has been no confirmation of dose response, as was initially asserted by the summary-level meta-analysis. No mechanism of harm has been identified. Although an association with increased mortality has been confirmed by patient-level meta-analysis, the strength of the signal has been inconsistent. The information suggests there is only an association between paclitaxel-coated devices and increased all-cause mortality, not causation. The authors encourage additional studies designed to follow long-term results after treatment with paclitaxel-coated devices, using real patient data, before a conclusion can be made.

The Safety of Paclitaxel-Coated Devices for Patients with Peripheral Artery Disease

PURPOSE OF REVIEW

Peripheral artery disease (PAD) is a common, debilitating disease that impacts 8.5 million Americans and carries a poor prognosis. The most common manifestation of lower extremity PAD is claudication-a condition which significantly reduces quality of life and functional status. Paclitaxel-coated balloons and stents (PCBs and PESs) represented a breakthrough in the ability to treat medication-refractory patients relative to bare metal stents (BMSs) and percutaneous transluminal angioplasty (PTA) because they improve primary patency rates, reduce target lesion revascularization (TLR), and minimize late-lumen loss for femoropopliteal lesions. As a result, paclitaxel-coated devices (PCDs) were swiftly established as the standard of care for revascularization of femoropopliteal artery disease. A recent meta-analysis of summary-level data demonstrated a late mortality signal for patients treated with paclitaxel-coated devices relative to uncoated devices. This has had a major impact on the vascular community and for the treatment of patients with PAD. Herein, we provide a detailed review of the available data on the late mortality signal associated with paclitaxel.

RECENT FINDINGS

In December of 2018, Katsanos et al. J Am Heart Assoc 7: e011245, 2018) published data from randomized-controlled trials (RCTs) that demonstrated an increase in mortality at 2 and 5 years in patients treated with PCDs involving the femoropopliteal arterial segment relative to patients treated with uncoated devices. As a result of this analysis, randomized trials were stopped and the FDA sent a letter to healthcare providers recommending restriction of use of these devices to patients at the highest risk of restenosis. As additional data emerged supporting the safety of these devices, the FDA organized an advisory committee meeting to review the available data and to determine a pathway forward. The FDA concluded that there were insufficient data to make a final decision regarding the safety of PCDs. They allowed these devices to remain on the market, but with revised safety labeling and updated their letter to healthcare providers to continue to restrict use to patients at highest risk of reintervention. The FDA also called for additional long-term data, including from RCTs and real-world data. To date, an updated patient-level meta-analysis of clinical trial data, RCTs with longer-term follow-up, and large observational studies have been conducted. While meta-analyses conducted using overlapping clinical trial data have found a persistent increase in mortality for those treated with PCDs, individual industry-sponsored RCTs and large observational studies have consistently failed to detect a corresponding mortality increase. To date, no mechanism linking paclitaxel to mortality has been observed. We are currently at an impasse for drawing definitive conclusions regarding the long-term safety of paclitaxel-coated devices. As we await enrollment in ongoing clinical trials, we must proceed with making reasonable decisions for our patients' care from the available data, as these devices have important clinical implications for our patients. A critical lesson that can be learned from this controversy is that, for future device trials, committing to long-term follow-up is crucial.

Femoral-popliteal peripheral artery disease: From symptom presentation to management and treatment controversies

Peripheral artery disease (PAD) is a common condition with increasing prevalence domestically and worldwide. Patients with PAD have a poor prognosis, as PAD is associated with high rates of myocardial infarction, ischemic stroke, and cardiovascular disease death. The primary symptom of PAD, claudication, significantly reduces quality of life and functional status and is associated with depression. In addition to several advances in medications for PAD over the last decade, endovascular device therapy has seen a significant breakthrough in the form of paclitaxel-coated devices (PCDs), which significantly reduce rates of restenosis relative to non-PCDs, a finding which has been demonstrated in numerous randomized clinical trials. After their introduction to the market in 2012 (paclitaxel-eluting stents) and 2014 (paclitaxel-coated balloons) their use surged as they replaced non-PCDs and were designated the first-line endovascular therapy by society guidelines. This trend was abruptly reversed, however, after a meta-analysis of summary-level data was published in December of 2018 that reported an elevated mortality associated with PCDs compared with non-PCDs 2-5 years after treatment. This meta-analysis has been criticized for considerable methodological flaws. The Food and Drug Administration conducted a review and concluded that insufficient data existed to make a definitive statement regarding the safety of PCDs. They called for restriction of the use of PCDs to the highest-risk patient populations. At the same time, the FDA deemed pursuing new RCTs to better evaluate PCDs unfeasible due to the high numbers of patients and long follow-up time that would be required. In this setting, real-world data emerged as a powerful source of information for the evaluation of PCDs. Real-world data offers advantages over randomized-controlled trials including expeditious access to and analysis of data and the availability of large numbers of patients. Several retrospective observational studies demonstrate no difference in long-term all-cause mortality in patients treated with PCDs relative to those treated with non-PCDs. This paclitaxel controversy has illustrated the critical role that real-world data is assuming in long-term safety monitoring of medical devices.

Experience using drug-coated balloon venoplasty for acquired pulmonary vein stenosis after radiofrequency ablation

Pulmonary vein stenosis is a rare but severe complication of catheter ablation for arterial fibrillation (AF). Symptoms include dyspnea, hemoptysis, recurrent pneumonia, and pulmonary hypertension. We herein discuss a 27-year-old male patient who presented with hemoptysis and dyspnea three months after catheter ablation for AF. Computed tomography demonstrated an occluded left inferior pulmonary vein (LIPV) and left lower lung edema secondary to severe stenosis of the LIPV. The patient underwent treatment, including drug-coated balloon (DCB) venoplasty. Treatment of pulmonary vein stenosis involving percutaneous interventions with balloon angioplasty and stenting carry a high risk of restenosis. DCB therapy may be used to prevent stenosis. <Learning objective: The use of a drug-coated balloon is feasible and may provide good long-term outcomes in acquired pulmonary vein stenosis after radiofrequency ablation.>.

Update on paclitaxel for femoral-popliteal occlusive disease in the 15 months following a summary level meta-analysis demonstrated increased risk of late mortality and dose response to paclitaxel

BACKGROUND

Peripheral vascular devices (stents and balloons) coated with paclitaxel were developed to address suboptimal outcomes associated with percutaneous revascularization procedures of the femoral-popliteal arteries. In randomized controlled trials (RCT), paclitaxel-coated devices (PCD) provided increased long-term patency and a decreased need for repeat revascularization procedures compared with uncoated devices. This finding resulted in the adoption of their use for endovascular lower extremity revascularization procedures. However, in late 2018 a study-level meta-analysis showed increased all-cause mortality at 2 years or more after the procedure in patients treated with PCDs. This review examines the subsequent data evaluation following the publication of the meta-analysis.

METHODS

We review the published responses of physicians, regulatory agencies, and patient advocates during 15-month period after the meta-analysis. We present the additional data gathered from RCTs that comprised the meta-analysis and safety outcomes from large insurance databases in both the United States and Europe.

RESULTS

Immediately after the publication of the meta-analysis, concern for patient safety resulted in less PCD use, the suspension of large RCTs evaluating their use, and the publication of a letter from the U.S. Food and Drug Administration informing physicians that there was uncertainty in the benefit-risk profile of these devices for indicated patients and that the potential risk should be assessed before the use of PCDs. Review of the meta-analysis found that a mortality signal was present, but criticisms included that the evaluation was performed on study-level, not patient-level data, and the studies in the analysis were heterogenous in device type, paclitaxel doses, and patient characteristics. Further, the studies were not designed to be pooled nor were they powered for evaluating long-term safety. Clinical characteristics associated with a drug effect or causal relationship were also absent. Specifically, there was no dose response, no clustering of causes of death, and a lack of signal consistency across geographic regions. As more long-term data became available in the RCTs the strength of the mortality signal diminished and analysis of real-world use in large insurance databases, showed that there was no significant increase in all-cause mortality associated with PCD use.

CONCLUSIONS

The available data do not provide definitive proof for increased mortality with PCD use. A key observation is that trial design improvements will be necessary to better evaluate the risk-benefit profile of PCDs.

Systematic evaluation of particle loss during handling in the percutaneous transluminal angioplasty for eight different drug-coated balloons

Paclitaxel drug coated balloons (DCBs) should provide optimal drug transfer exclusively to the target tissue. The aim of this study was to evaluate the particle loss by handling during angioplasty. A robotic arm was developed for systematic and reproducible drug abrasion experiments. The contact force on eight different commercially available DCB types was gradually increased, and high-resolution microscopic images of the deflated and inflated balloons were recorded. Three types of DCBs were classified: no abrasion of the drug in both statuses (deflated and inflated), significant abrasion only in the inflated status, and significant abrasion in both statuses. Quantitative measurements via image processing confirmed the qualitative classification and showed changes of the drug area between 2.25 and 45.73% (13.28 ± 14.29%) in the deflated status, and between 1.66 and 40.41% (21.43 ± 16.48%) in the inflated status. The structures and compositions of the DCBs are different, some are significantly more susceptible to drug loss. Particle loss by handling during angioplasty leads to different paclitaxel doses in the target regions for same DCB types. Susceptibility to involuntary drug loss may cause side effects, such as varying effective paclitaxel doses, which may explain variations in studies regarding the therapeutic outcome.

Combination of Percutaneous Rotational Thrombectomy and Drug-Coated Balloon for Treatment of Femoropopliteal Artery Nonembolic Occlusion: 12-Month Follow-up

PURPOSE

To evaluate safety and efficacy of percutaneous mechanical thrombectomy using the Rotarex catheter combined with drug-coated balloon (DCB) in treatment of femoropopliteal artery occlusive disease.

MATERIALS AND METHODS

Between January 2016 and February 2018, 81 patients with acute or subacute femoropopliteal artery occlusions were treated with the Rotarex catheter combined with DCB. Lesions were classified according to the onset of symptoms as acutely (< 14 d) or subacutely (14 d to 3 mo) occluded. The mean lesion length was 12.1 cm ± 6.7. The primary endpoint was target lesion patency at 1 year as evaluated by duplex ultrasound (peak systolic velocity ratio < 2.4) and freedom from clinically indicated target lesion revascularization. Amputation rate, major adverse events, and ankle-brachial index at 12 months were evaluated.

RESULTS

Technical success rate was 100% (n = 81). Bailout stents were necessary in 14 patients owing to residual stenosis or flow-limiting dissection. Additional thrombolysis was applied in 10 interventions. No major adverse events occurred during hospital stay. There were 9 restenosis cases during the 12-month follow-up period. Primary patency rate was 87.3% (62/71), and freedom from target lesion revascularization rate was 90.1% (64/71). Ankle-brachial index significantly increased from 0.46 ± 0.15 to 0.77 ± 0.14 during follow-up. The amputation rate was 1.4% at 12 months.

CONCLUSIONS

These initial data from 2 centers suggest that the combination of the Rotarex catheter and DCB may be safe and effective for treatment of acute or subacute thrombotic femoropopliteal occlusion with superior immediate and midterm results achieved.

Retained Functionality of Atherosclerotic Human Arteries Following Photoactivated Linking of the Extracellular Matrix by Natural Vascular Scaffolding Treatment

In this study, we investigated natural vascular scaffolding (NVS) treatment on vascular functionality using freshly isolated human popliteal arteries in vitro. Arteries were exposed to intraluminal NVS treatment consisting of a compound (4 amino-1,8-naphthalimide) photoactivated by a 450-nm light-emitting light fiber placed inside the artery. This procedure results in covalent linking between the extracellular matrix proteins to achieve a larger vessel diameter post-angioplasty and minimizing elastic recoil. Immediately following NVS treatment, rings were cut from the treated arteries and mounted in organ baths for contractility testing in response to U46619 and sodium nitroprusside. We also investigated the effect of NVS treatment on IL-6 cytokine release from vascular rings following a 4-h organoculture post-NVS treatment. Based on our results, we conclude that exposure of the vessels to NVS treatment does not adversely affect the contractile responsiveness of the vascular smooth muscle and exerts no pro-inflammatory effect. Graphical abstract.

Stellarex drug-coated balloon: a technology evaluation

The Stellarex® drug-coated balloon (DCB) is an over-the-wire dual lumen catheter with a distally premounted semi-compliant balloon, which has a low dose (2 μg/mm² of the expanded balloon surface) paclitaxel coating. Its hybrid formulation, made of amorphous and crystalline paclitaxel combined with a polyethylene glycol excipient, provides maintenance of coating integrity and adequate drug release. This balanced combination of amorphous and crystalline paclitaxel is able to maintain drug on the surface during handling and balloon tracking, with an effective drug transfer to vessel wall in the lesion site. Clinical data associated with Stellarex balloon are growing and confirm clinical effectiveness over a long-term follow-up without any possible signal of a reduced safety for treated patients.

Effect of drug-coated balloons in treatment of stenosis of the femoral artery and vein bypass graft not responding to plain old balloon angioplasty: a case report

Background

The use of drug-coated balloons (DCBs) with anti-proliferative agents in treating femoropopliteal lesions was approved in Japan in 2017. A better limb salvage rate or amputation-free rate of DCBs relative to plain old balloon angioplasty (POBA) has been reported; however, there is little evidence of the direct effect on intimal hyperplasia (IH).

Case presentation

A 70-year-old man with chronic limb-threatening ischemia and foot gangrene had undergone bypass surgery from the left common femoral artery to the dorsalis pedis artery 2 years earlier. We evaluated the bypass graft using ultrasonography and found stenosis around the proximal anastomotic site, presumably due to IH. POBA was performed every 3 months due to the repeated re-stenosis of the lesion. Since using the DCB, no restenosis has been detected to date (10 months).

Conclusion

DCB might be an effective tool for treating re-stenosis due to IH or vein grafts that do not respond to POBA.

Oral Resolvin D1 attenuates early inflammation but not intimal hyperplasia in a rat carotid angioplasty model

Inflammation ensuing from vascular injury promotes intimal hyperplasia (IH) and restenosis. Resolvin D1 (RvD1) is a lipid mediator that attenuates IH in vivo when delivered locally to the vessel wall in animal models. We tested the hypothesis that peri-procedural oral administration of RvD1 could blunt the local inflammatory response to angioplasty, and attenuate downstream IH. Carotid angioplasty was performed on rats fed with either RvD1 or vehicle through oral gavage, starting one day prior to injury until post-operative day (POD) 3 or 14 when arteries were harvested. To study pharmacokinetics and bioactivity of oral RvD1, we measured plasma RvD1 by ELISA, whole blood phagocytosis activity using flow cytometry, and cAMP levels in the thoracic aorta by ELISA. Carotid arteries were harvested on POD3 for staining (anti-CD45, anti-Myeloperoxidase (MPO), anti-Ki67 or dihydroethidium (DHE) for reactive oxygen species), mRNA expression of target genes (quantitative RT-PCR), or on POD14 for morphometry (elastin stain). RvD1 plasma concentration peaked 3 h after gavage in rats, at which point we concurrently observed an increase in circulating monocyte phagocytosis activity and aortic cAMP levels in RvD1-treated rats vs. vehicle. Oral RvD1 attenuated local arterial inflammation after angioplasty by reducing CD45+, MPO+, Ki67+ cells, and DHE staining intensity. Oral RvD1 also reduced the expression of several pro-inflammatory genes within the injured vessels. However, oral RvD1 did not significantly reduce IH. Oral RvD1 attenuated acute inflammation within the arterial wall after angioplasty in rats, but did not significantly affect IH.

Paclitaxel-Based Devices for the Treatment of PAD: Balancing Clinical Efficacy with Possible Risk

PURPOSE OF REVIEW

Paclitaxel-based endovascular devices have become the standard of care in symptomatic, medication-refractory peripheral artery disease (PAD) and in critical limb ischemia (CLI). This review examines the data on the efficacy and safety of these devices relative to standard balloon angioplasty (PTA) and bare metal stents (BMS).

RECENT FINDINGS

Randomized controlled trials (RCTs) have found that peripheral devices coated with paclitaxel result in superior patency rates and decreased target lesion revascularization (TLR) compared with non-drug-coated devices. Recently, a meta-analysis of randomized controlled trials unexpectedly reported an increase in mortality in patients treated with paclitaxel-coated devices (PCDs), resulting in the pausing of ongoing trials and a warning of safety from the FDA. Observational data that has been published since this time has not supported this safety concern. PAD is a common disease that severely impacts quality and length of life. PCDs are a promising therapy for patients with PAD, offering a more effective and durable intervention when compared with traditional PTA/BMS. A meta-analysis of RCTs identified a signal of harm with these devices which has now been replicated by the FDA. However, there is significant missing data from the trials analyzed by the meta-analysis and FDA, no plausible mechanism linking paclitaxel to death, and no correlation between paclitaxel dose and mortality. Analyses in observational data have found no safety signal. An FDA panel evaluating the validity of this late-mortality signal recently adjourned, emphasizing that the available data is incomplete. PCDs will remain on the market, and an active discussion is underway for developing an approach for improved post-market surveillance, device-labeling, and cause of death adjudication.

Risk of Death Following Application of Paclitaxel-Coated Balloons and Stents in the Femoropopliteal Artery of the Leg: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background Several randomized controlled trials ( RCT s) have already shown that paclitaxel-coated balloons and stents significantly reduce the rates of vessel restenosis and target lesion revascularization after lower extremity interventions. Methods and Results A systematic review and meta-analysis of RCT s investigating paclitaxel-coated devices in the femoral and/or popliteal arteries was performed. The primary safety measure was all-cause patient death. Risk ratios and risk differences were pooled with a random effects model. In all, 28 RCT s with 4663 patients (89% intermittent claudication) were analyzed. All-cause patient death at 1 year (28 RCT s with 4432 cases) was similar between paclitaxel-coated devices and control arms (2.3% versus 2.3% crude risk of death; risk ratio, 1.08; 95% CI, 0.72-1.61). All-cause death at 2 years (12 RCT s with 2316 cases) was significantly increased in the case of paclitaxel versus control (7.2% versus 3.8% crude risk of death; risk ratio, 1.68; 95% CI, 1.15-2.47; -number-needed-to-harm, 29 patients [95% CI , 19-59]). All-cause death up to 5 years (3 RCT s with 863 cases) increased further in the case of paclitaxel (14.7% versus 8.1% crude risk of death; risk ratio, 1.93; 95% CI , 1.27-2.93; -number-needed-to-harm, 14 patients [95% CI , 9-32]). Meta-regression showed a significant relationship between exposure to paclitaxel (dose-time product) and absolute risk of death (0.4±0.1% excess risk of death per paclitaxel mg-year; P<0.001). Trial sequential analysis excluded false-positive findings with 99% certainty (2-sided α, 1.0%). Conclusions There is increased risk of death following application of paclitaxel-coated balloons and stents in the femoropopliteal artery of the lower limbs. Further investigations are urgently warranted. Clinical Trial Registration URL : www.crd.york.ac.uk/PROSPERO . Unique identifier: CRD 42018099447.

Percutaneous Coronary Intervention in the Elderly: Are Drug-coated Balloons the Future?

Background:

Balloon angioplasty revolutionised percutaneous treatment for coronary ar-tery disease four decades ago, but vessel-threatening dissections, elastic recoil and restenosis were major drawbacks to an otherwise successful long-lasting intervention. Subsequent advances with bare metal stents and then drug eluting stents followed, aiming to mitigate the risks of acute vessel closure and restenosis. However, stent implantation often necessitates dual antiplatelet therapy for a pro-longed period of time, which in itself can lead to adverse outcomes, especially in the frail elderly pop-ulation at higher risk of bleeding. More recently, bioabsorbable stents have been implemented in clini-cal practice enabling earlier intimal coverage of the stent and apposition.

However, another addition to the armamentarium of percutaneous coronary intervention is the use of drug-coated balloons without the need for deploying any coronary stents or scaffolds. Drug-coated balloons are semi-compliant balloons coated with an antiproliferative agent that is rapidly released on contact with the vessel intima exerting an anti-restenotic effect. The absence of a metallic scaffold means that the need for antiplatelet therapy can potentially be negated in the longer term if required. In this article, we will review the history of percutaneous coronary intervention and the available evi-dence for the appropriate use of drug-coated balloons especially in the elderly population.

Conclusion:

We will conclude this review by demonstrating the potential use of drug-coated balloon rather percutaneous stenting through case examples.

The use of an occlusion perfusion catheter to deliver paclitaxel to the arterial wall

AIM

Nonstent drug delivery platforms have recently emerged as an alternative treatment of peripheral arterial disease. Perfusion catheters have the potential to directly deliver antiproliferative agents to the medial arterial layer to prevent restenosis. The purpose of this study was to therefore determine the effectiveness of a perfusion catheter to deliver paclitaxel, a proven antiproliferative agent, to combat restenosis.

METHODS

A benchtop model was utilized to determine the varying parameters of a novel occlusion perfusion catheter to maximize paclitaxel delivery using pharmacokinetic evaluation and fluorescent microscopy. Parameters tested included concentration of paclitaxel, delivery pressure, duration of delivery, and the use of an excipient. In addition, bilateral rabbit iliac arteries were treated with the perfusion catheter and pharmacokinetic evaluation performed at 1 hour, 1 day and 3 days.

RESULTS

Benchtop testing demonstrated uniform and circumferential penetration of paclitaxel within the treated arteries. The results of the ex vivo test identified two groups with and without an excipient with similar loading conditions (with excipient: 15.4±8.6 ng/mg vs without excipient: 8.9±6.9 ng/mg, P=.77). The in vivo pharmacokinetic analysis of these two groups demonstrated the use of contrast agent increased arterial paclitaxel levels and maintained initial paclitaxel dosing up to 3 days (With excipient: 1 hour: 107±62 ng vs 3 days: 40±23 ng, P=.824; No excipient: 1 hour: 247±120 ng vs 3 days: 2.92±2.9 ng, P=.009).

CONCLUSIONS

These results demonstrate the feasibility to deliver paclitaxel directly to the medial layer of an artery via a perfusion catheter.

Mid-term clinical outcomes after bailout drug-eluting stenting for suboptimal drug-coated balloon results: Insights from a Milan registry

BACKGROUND

Drug-coated balloon (DCB) is an alternative to drug-eluting stent (DES) for the treatment of small vessel or in-stent restenosis (ISR) lesions, with bailout stenting reserved for poor results after DCB inflation (residual stenosis or dissection). Data regarding bailout stenting with DES are limited. The aim of this study was to evaluate clinical outcomes after bailout stenting with DES for suboptimal DCB results.

METHODS

From June 2009 to December 2015, patients who underwent bailout DES implantation for suboptimal results after DCB (residual stenosis > 30% or type C-F dissection) in 2 high-volume centers in Italy were analyzed. The primary endpoint was target lesion failure (TLF) defined as composite of cardiac mortality, target vessel myocardial infarction (MI) and target lesion revascularization (TLR).

RESULTS

A total of 103 patients (125 lesions) were analyzed. Mean age was 68.8 ± 9.5 years, 21.4% were diabetic, and 92.2% underwent PCI for stable angina. The left anterior descending artery was most commonly treated (35.2%), followed by right coronary artery (17.6%) and left circumflex artery (17.6%). Lesion complexity was high (type B2/C: 88.8%) and 24.8% were ISR lesions. During the follow-up period (median: 858 days [interquartile range: 467-1665]), the TLF rate was 4.3% at 1 year and 15.4% at 2 years, and mainly driven by TLR (3.3% at 1 year, 14.5% at 2 years, respectively). There were no target vessel MI or definite/probable stent thrombosis events.

CONCLUSIONS

Bailout stenting with DES for suboptimal DCB results is a feasible and safe strategy at mid-term follow-up.

Mesoporous carbon nanoshells for high hydrophobic drug loading, multimodal optical imaging, controlled drug release, and synergistic therapy

Loading and controlled release of sufficient hydrophobic drugs to tumor cells has been the bottleneck in chemotherapy for decades. Herein we report the development of a fluorescent and mesoporous carbon nanoshell (FMP-CNS) that exhibits a loading capacity for the hydrophobic drug paclitaxel (PTX) as high as ∼80 wt% and releases the drug in a controllable fashion under NIR irradiation (825 nm) at an intensity of 1.5 W cm^-2. The high drug loading is primarily attributed to its mesoporous structure and to the supramolecular π-stacking between FMP-CNSs and PTX molecules. The FMP-CNS also exhibits wavelength-tunable and upconverted fluorescence properties and thus can serve as an optical marker for confocal, two-photon, and near infrared (NIR) fluorescence imaging. Furthermore, our in vitro results indicate that FMP-CNSs demonstrate high therapeutic efficacy through the synergistic effect of combined chemo-photothermal treatment. In vivo studies demonstrate marked suppression of tumor growth in mice bearing rat C6 glioblastoma after administration with a single intratumoral injection of PTX-loaded FMP-CNS.

Delivering therapeutics in peripheral artery disease: challenges and future perspectives

Targeted and sustained delivery of biologicals to improve neovascularization has been focused on stimulation angiogenesis. The formation of collaterals however is hemodynamically much more efficient, but as a target of therapy has been under-utilized. Although there is good understanding of the molecular processes involving collateral formation and there are interesting drugable candidates, the need for targeting and sustained delivery is still an obstacle towards safe and effective treatment. Molecular targeting with nanoparticles of liposomes is promising and so are peri-vascularly delivered polymer-based protein reservoirs. These developments will lead to future arteriogenesis strategies that are adjunct to current revascularization.

Systematic Review and Meta-analysis of Randomized Controlled Trials of Paclitaxel-Coated Balloon Angioplasty in the Femoropopliteal Arteries: Role of Paclitaxel Dose and Bioavailability

PURPOSE

To provide a qualitative analysis and quantitative synthesis of randomized controlled trials (RCTs) investigating paclitaxel-coated balloons (PCBs) in the femoropopliteal artery.

METHODS

PubMed, EMBASE, AMED, Scopus, CENTRAL, online content, and abstracts from international meetings were last screened in April 2015 for eligible RCTs using the PRISMA selection process. Risk of bias was assessed using the Cochrane Collaboration's tool, and quality of evidence was evaluated with the GRADE system. Outcome measures included late lumen loss (LLL) at 6 months and event rates of major limb amputations, binary lesion restenosis, and target lesion revascularization (TLR). Pooled treatment effects were analyzed in a random effects model to account for clinical heterogeneity; the outcomes are presented as the rate ratios (RRs) and their 95% confidence intervals (CIs). Extensive meta-regression was performed to analyze potential confounders. The review was registered in the PROSPERO database (CRD42015023938; www.crd.york.ac.uk/PROSPERO).

RESULTS

Eleven RCTs with 1609 subjects (1403 claudicants and 206 patients with critical limb ischemia) with medium-length femoropopliteal lesions (mean range 5.1-11.9 cm) were included. There was consistently high-quality evidence supporting the clear superiority of PCBs in terms of reduced LLL (mean difference -0.89 mm, 95% CI -1.14 to -0.64, p<0.001), less binary restenosis (RR 0.47, 95% CI 0.37 to 0.61, p<0.001), and fewer TLR events (RR 0.33, 95% CI 0.22 to 0.49, p<0.001). Major amputations were rare in both active and control arms (pooled event rate: 0.7%, 95% CI 0.3% to 1.2%). Results were stable across all potential risk modifiers and in the presence of stents as well. There was high-quality evidence that the dose of paclitaxel was related to the magnitude of the treatment effect; standard dose (3.0-μg and 3.5-μg) PCBs were significantly more effective compared with low-dose 2-μg PCB in reducing both restenosis (RR 2.1, 95% CI 1.2 to 3.4, p<0.001) and TLR (RR 2.5, 95% CI 1.9 to 3.8, p<0.001).

CONCLUSION

PCBs reduce by more than half the rates of restenosis and TLR in the femoropopliteal artery regardless of stent placement. Biologic effect size may vary according to paclitaxel bioavailability.

An update on the clinical use of drug-coated balloons in percutaneous coronary interventions

INTRODUCTION

Drug-coated balloons (DCB) promise to deliver anti-proliferative drugs and prevent restenosis leaving nothing behind. Although, randomized clinical trials have demonstrated their efficacy for the treatment of in-stent restenosis, clinical evidence supporting their use in other coronary applications is still lacking.

AREAS COVERED

This review summarizes the development status of clinically available DCB technologies and provides an update on the current data for their coronary use.

EXPERT OPINION

Current generation DCB prevent restenosis by delivering paclitaxel particles on the surface of the vessel wall. Although clinically available technologies share a common mechanism of action, important differences in pharmacokinetic behavior and safety profiles do exist. Future technological improvements include the development of coatings displaying: high transfer efficiency; low particle embolization potential; and alternative drug formulations. Optimized balloon-based delivery systems and drug encapsulation technologies also promise to improve the technical limitations of current generation DCB. Although proving clinical superiority against DES may prove to be difficult in mainstream applications (i.e., de novo), new generation DCB technologies have the potential to achieve a strong position in the interventional field in clinical settings in which the efficacy of DES use is not proven or justified (i.e., bifurcations).

Effect of the association of 1-methyl-DL-tryptophan with paclitaxel on the expression of indoleamine 2,3-dioxygenase in cultured cancer cells from patients with breast cancer

Breast cancer is the most common type of cancer among women and the survival of patients affected by it is increasing, mainly due to several new approaches in early diagnosis and more effective treatments. The enzyme indoleamine 2,3-dioxygenase (IDO) is expressed in many cells, including tumor cells. IDO acts by inhibiting the proliferation of T lymphocytes, thus compromising their cytotoxic activity. 1-Methyl-DL-tryptophan (1MT) is a competitive inhibitor of IDO, which blocks its immunosuppressive effect. Paclitaxel is an antineoplastic drug largely used in breast cancer therapy. Thus, this study aimed to determine the in vitro effect of the association of 1MT and paclitaxel chemotherapy, as an approach to reduce tumor growth. It is believed that this would allow the restoration of T lymphocyte proliferation capability and its cytotoxic response. The supplemented cultures showed that the most significant differences in the expression of IDO were observed in the group treated with paclitaxel associated with 1-MT continuous supplementation, reducing enzyme expression from 12.06 to 3.56 %. This association was more effective in reducing IDO expression and could collaborate in developing a new therapeutic strategy for breast cancer treatment.