Axitinib: from preclinical development to future clinical perspectives in renal cell carcinoma

Introduction: Based on extensive preclinical data and abundant evidence for clinical activity, vascular endothelial growth factor receptor (VEGFR) inhibitors are currently standard of care for metastatic renal cell carcinoma (mRCC). Axitinib is one of the most selective molecules in the class of anti-angiogenic agents, which confers an optimal profile between its safety and anti-cancer activity spectrum.

Area covered: In this review, the authors discuss the different stages that lead to the approval of axitinib in the clinic as well as the current perspectives for its clinical use with other promising therapies in mRCC such as immune checkpoint inhibitors and vaccines.

Expert opinion: In 2015, axitinib has emerged as one of the major agents used in mRCC. Based on robust preclinical data, this highly specific VEGFR inhibitor continues to be evaluated in different indications, including the adjuvant setting but also sequential administration with other molecularly targeted agents or combinations with immune therapies.     

Simvastatin: present and future perspectives

Simvastatin is lipophilic statin with a short half-life that is primarily metabolized by CYP450 3A4. At doses of 5 – 80 mg, simvastatin lowers LDL cholesterol by 25 – 50%. Simvastatin has been shown to reduce the risk of cardiovascular disease by 35% and overall mortality by up to 30% over 5 years. The recommended starting dose of simvastatin 40 mg is approved as a lipid-lowering agent and for all high-risk patients, including those with cardiovascular disease and diabetes, regardless of the baseline LDL level. Simvastatin dose should be adjusted in those receiving CYP3A4 inhibitors, gemfibrozil, or ciclosporin, amiodarone, or in those with severe renal insufficiency. Coformulation of simvastatin with ezetimibe is now available, and coformulation with extended release niacin is under development.     

Simvastatin: present and future perspectives

Simvastatin is lipophilic statin with a short half-life that is primarily metabolized by CYP450 3A4. At doses of 5 - 80 mg, simvastatin lowers LDL cholesterol by 25 - 50%. Simvastatin has been shown to reduce the risk of cardiovascular disease by 35% and overall mortality by up to 30% over 5 years. The recommended starting dose of simvastatin 40 mg is approved as a lipid-lowering agent and for all high-risk patients, including those with cardiovascular disease and diabetes, regardless of the baseline LDL level. Simvastatin dose should be adjusted in those receiving CYP3A4 inhibitors, gemfibrozil, or ciclosporin, amiodarone, or in those with severe renal insufficiency. Coformulation of simvastatin with ezetimibe is now available, and coformulation with extended release niacin is under development.     

Smoking cessation: present status and future perspectives

Smoking is the leading cause of premature mortality in western countries and it is important for smokers to stop as early as possible. Several approaches for cessation are available but they lack high levels of efficacy. Consequently, there is a compelling need for more effective approaches and safer medications to aid smokers in achieving long-term abstinence. Expanding knowledge in our understanding of the mechanisms involved in tobacco dependence is leading to the development of novel therapies and vaccines for smoking cessation, many of which are currently in the advanced stage of development and offer promise. Here we will review efficacy and safety data from human clinical trials of current and emerging therapies and tools which are approved or undergoing investigation.     

Advanced renal cell carcinoma: current and emerging management strategies

Management of renal cell carcinoma (RCC) has made considerable progress in recent years, and new emerging strategies are being developed. On the basis of the results of two randomised studies in the early 2000s, nephrectomy has now become the standard as cytoreductive surgery before embarking on systemic treatment with cytokines. Interleukin (IL)-2 and interferon were the standard treatment in metastatic RCC (MRCC) until 2006. The efficacy of these two drugs, which have now been used for >20 years in MRCC, is still controversial. On the basis of many studies, these drugs should not be given to patients with a poor prognosis. In patients with good prognostic factors, a cytokine-based regimen should remain the standard as either a high-dose IL-2 or subcutaneous regimen. In patients with intermediate risk, the results of the French Percy Quattro study encourage the use of new targeted therapies as first-line therapy.Development of targeted therapies in RCC has been necessary largely because the Von Hippel-Lindau (VHL) gene is often mutated in sporadic RCC. VHL protein abnormalities lead to accumulation of hypoxia-inducible factor (HIF)-alpha and activation of a series of genes, including vascular endothelial growth factor (VEGF), thus inducing angiogenesis. Results from many recent studies with new agents that block the VEGF pathway have been reported and offer new strategic options for patients with MRCC. Sunitinib and sorafenib, two tyrosine kinase inhibitors, improve progression-free survival in RCC compared with standard treatment and have been recently approved. Temsirolimus, a mammalian target of rapamycin inhibitor regulating HIF-alpha, improves survival in RCC patients with poor risk features. Bevacizumab, a monoclonal antibody against VEGF, has shown very promising efficacy. Overall, treatment of MRCC is currently moving from the cytokine era to the targeted agent era. However, many questions still remain regarding the efficacy of combination treatments and on the best way to achieve complete remission, which is probably the best hope of curing MRCC.     

MRI contrast agents: current status and future perspectives

Magnetic Resonance Imaging (MRI) is increasingly used in clinical diagnostics, for a rapidly growing number of indications. The MRI technique is non-invasive and can provide information on the anatomy, function and metabolism of tissues in vivo. MRI scans of tissue anatomy and function make use of the two hydrogen atoms in water to generate the image. Apart from differences in the local water content, the basic contrast in the MR image mainly results from regional differences in the intrinsic relaxation times T(1) and T(2), each of which can be independently chosen to dominate image contrast. However, the intrinsic contrast provided by the water T(1) and T(2) and changes in their values brought about by tissue pathology are often too limited to enable a sensitive and specific diagnosis. For that reason increasing use is made of MRI contrast agents that alter the image contrast following intravenous injection. The degree and location of the contrast changes provide substantial diagnostic information. Certain contrast agents are predominantly used to shorten the T(1) relaxation time and these are mainly based on low-molecular weight chelates of the gadolinium ion (Gd(3+)). The most widely used T(2) shortening agents are based on iron oxide (FeO) particles. Depending on their chemical composition, molecular structure and overall size, the in vivo distribution volume and pharmacokinetic properties vary widely between different contrast agents and these largely determine their use in specific diagnostic tests. This review describes the current status, as well as recent and future developments of MRI contrast agents with focus on applications in oncology. First the basis of MR image contrast and how it is altered by contrast agents will be discussed. After some considerations on bioavailability and pharmacokinetics, specific applications of contrast agents will be presented according to their specific purposes, starting with non-specific contrast agents used in classical contrast enhanced magnetic resonance angiography (MRA) and dynamic contrast enhanced MRI. Next targeted contrast agents, which are actively directed towards a specific molecular target using an appropriate ligand, functional contrast agents, mainly used for functional brain and heart imaging, smart contrast agents, which generate contrast as a response to a change in their physical environment as a consequence of some biological process, and finally cell labeling agents will be presented. To conclude some future perspectives are discussed.     

The fluoroquinolone antibacterials: past, present and future perspectives

The history of the development of the quinolones is described from the first quinolone, nalidixic acid, via the first 6-fluorinated quinolone norfloxacin, to the latest extended-spectrum fluoroquinolones. The structural modifications made to the basic quinolone and naphthyridone nucleus and to the side chains have allowed improvements to be made such that the next group of fluoroquinolones after norfloxacin, exemplified by ciprofloxacin, had high activity against gram-negative species and a number of atypical pathogens, good-to-moderate activity against gram-positive species and were well absorbed and distributed. These compounds have been successfully used in the clinic for a decade and the size of the market has risen in recent years to only a little less than that for penicillins and macrolides. Notwithstanding the broad spectrum of these compounds, defects became evident. The growth in understanding of structure activity relationships with fluoroquinolones has enabled the development of even better compounds. The targets in fluoroquinolone research during the last few years include: improvements in pharmacokinetic properties, greater activity against gram-positive cocci and anaerobes, activity against fluoroquinolone-resistant strains, and improvements in activity against non-fermentative gram-negative species. The compounds developed in the recent years have fulfilled some but not all of these goals; improved bioavailability is one target achieved with most of the more recent compounds allowing for once-daily dosing. Gatifloxacin, moxifoxacin and trovafloxacin have all greatly improved the activity against gram-positive cocci, particularly pneumococci, and against anaerobes. They are not quite as active as ciprofloxacin against Enterobacteriaceae, and show no substantial improvements in activity against non-fermentative species. Clinafloxacin, gemifloxacin and sitafloxacin have even better activity against gram-positive cocci and are as active as ciprofloxacin against most gram-negatives, though gemifloxacin is less active than the other new compounds against gram-negative anaerobes. These three compounds do retain some activity against a number of ciprofloxacin-resistant species (gram-positive and gram-negative), but whether this activity will be adequate for clinical use is at present unclear. Both clinafloxacin and sitafloxacin contain a chloro substituent at position 8 of the quinolone nucleus. A halogen at this position in a number of compounds, though giving good activity, has also been associated with phototoxicity. Several fluoroquinolones have had to be withdrawn or strictly limited in their use post-marketing and in some cases no obvious relationship can be seen between the adverse effects and structural features, making this an area for urgent research.     

分子靶向药物舒尼替尼治疗肾细胞癌

肾细胞癌(RCC)具有高转移性、易复发且对放、化疗不敏感三大特征,免疫治疗仅对少数患者有效.随着RCC分子生物学研究的进展,临床转移性RCC的靶向治疗不断取得新突破.分子靶向药物舒尼替尼(sunitinib)治疗RCC疗效确切,但其诸多不良反应和并发症仍需引起足够重视.     

Novel treatment strategies in clear-cell metastatic renal cell carcinoma

Metastatic renal-cell carcinoma (mRCC) is highly resistant to cytotoxic agents or hormones and is currently mainly treated with cytokine-based therapy. Transient responses and moderate survival advantages have been achieved in a subset of patients with these aspecific biological response modifiers. Side-effects are considerable, especially with high-dose interleukin (IL)-2. Efforts made in the field of specific immunotherapy have focused on optimization of dendritic cell vaccination and on administration of monoclonal antibodies, either cold (unconjugated) or hot (radioactively labeled). Furthermore, allogeneic bone marrow transplantation is able to induce remissions but, regrettably, is related to substantial morbidity and mortality. Neutralization of the biological activity of some immunosuppressive cytokines produced by RCC (IL-6 and tumor necrosis factor-alpha) with monoclonal antibodies is currently under investigation. Insights gained into the processes and pathways underlying carcinogenesis have led to the development of new treatment strategies. These treatments can be used for clear cell RCC, since they focus on blocking gene products that are upregulated by mutations in the von Hippel-Lindau gene. Specific strategies include anti-vascular endothelial growth factor monoclonal antibody (bevacizumab) or inhibition of its receptor kinases (oral SU11248 or PTK787), or targeting the Raf kinase pathway (by BAY 43-9006) or the mammalian target of rapamycin (mTOR) pathway (by CCI-779). Early clinical results are promising, but their place in the treatment of RCC has to be determined.     

Toxicities of targeted agents in advanced renal cell carcinoma

The targeted therapies available to treat metastatic kidney cancer include vascular endothelial growth factor (VEGF) inhibitors, bevacizumab, sorafenib, sunitinib, pazopanib, and the mTor inhibitors temsirolimus and everolimus. These agents have significantly improved patient outcomes but are associated with toxicities. The most common toxicities seen with the VEGF inhibitors are hypertension, fatigue, and hand- foot syndrome. The mTor inhibitors exhibit a different toxicity profile which includes hyperglycemia and hypertriglyceridemia. Recognition and understanding the mechanism of the toxicities is crucial for optimal patient management.     

肾癌靶向治疗药物的研究进展

肾细胞癌的发病率占恶性肿瘤的2%,传统的治疗方法是使用细胞因子(干扰素或者白介素-2),但这些免疫治疗生存优势小,疗效有限,需要开发更有效的药物。肾癌分子生物学的研究,揭示血管内皮生长因子和相关受体以及RAS/RAF/MEK/ERK和PI3K/Akt/mTOR信号传导通路与肾癌的发病密切相关,这些受体和通路促进了肿瘤细胞的生长和增殖。最近开发的药物,包括酪氨酸激酶抑制剂、单克隆抗体和mTOR抑制剂,能靶向作用于肾癌的酪氨酸激酶和细胞内通路,产生抗肿瘤作用。文中总结了肾癌发病的分子生物学机制,靶向治疗药物的作用机制以及临床评价的研究进展。     

Probiotics as biotherapeutic agents: present knowledge and future prospects

Since the early observations of Elie Metchnikoff, a wealth of experiments have described the use of selected microorganisms, mainly belonging to the lactic acid bacteria family, for the prevention or treatment of a variety of pathological situations. Nevertheless, the mechanisms underlying the proposed actions remain vastly unknown, partly as a consequence of the complexity of the gastro-intestinal ecosystem with which these biotherapeutic agents are expected to interact, but also because of the increasing variety of strains considered to have potential probiotic characteristics. During the past decades, however, the beneficial effect of specific strains in preventing or treating intestinal disorders has been substantiated by well-controlled clinical trials. Increasing evidence, including human studies, is also supporting the immunomodulatory role attributed to given lactic acid bacterial strains. The desire by consumers to use natural methods for health maintenance rather than long-term chemotherapeutic agents (i.e. antibiotics), linked to their expectation that food becomes a source of prolonged well-being, supports the speculation that the probiotic market will expand rapidly. Much of this growth will also depend on the reliability of claims that these products will bare. Therefore, the legislator will have to provide clear rules and regulations which will depend on measurable biomarkers and criteria based on scientific evidence. These commercial and legislative needs will hopefully provide scientists with the resources necessary to conduct the multidisciplinary research required to establish facts and mechanisms of action for carefully selected probiotic strains. These research results will probably be as essential for the positioning of probiotic preparations as either a food, a food supplement or as pharmaceutical preparation.     

VEGF inhibitors in metastatic renal cell carcinoma: current therapies and future perspective

Metastatic renal cell carcinoma (RCC) is predominantly refractory to treatment with traditional cytotoxic chemotherapies, and until recently management options were limited to immunotherapy, palliative care, or phase I trials. The past five years have witnessed a major change in the treatment of advanced RCC with the introduction of targeted therapies that derive their efficacy through affecting angiogenesis. The main class of agents involves drugs that target the vascular endothelial growth factor (VEGF). Several VEGF inhibitors are now approved for the treatment of metastatic RCC. The field is expanding rapidly with goals including 1) developing novel more potent and better tolerated agents and 2) defining the role of combination and sequential anti-VEGF regimens.     

Neoadjuvant and adjuvant strategies in renal cell carcinoma: more questions than answers

The current standard treatment for early stage (I-III) renal cell cancer (RCC) is surgery. While the prognosis of stage I tumors is excellent, stage II and particularly stage III have a high risk of relapse. The adjuvant treatment of patients with RCC remains an area of investigation, with patient selection being a key aspect. There are currently two prognostic nomograms to establish the risk of relapse in patients with resected RCC. The results of earlier studies of adjuvant therapy, including the use chemotherapy and/or immunotherapy after nephrectomy have failed to show any benefit in the outcome of patients at risk of developing local recurrence or distant metastases. Two recent phase III trials with vaccines (autologous tumor cell vaccine and autologous tumor-derived heat shock protein peptide complex-96) have shown promising, albeit still preliminary, results. In the metastatic RCC setting, recent advances in the molecular understanding of oncogenic pathways have led to the development of new therapeutic strategies with the use of targeted therapies in the adjuvant setting. Neoadjuvant treatment is another treatment modality currently being evaluated for patients with early disease and in patients with metastatic RCC with inoperable primary tumors. The questions that remain unanswered include activity of these agents in early stages of the disease, patient selection, optimal start time of the adjuvant treatment, and finally, the optimal length of treatment.     

Cardiac stem cell therapy: present and future

The last decade has seen great strides in the drug treatment of myocardial infarction and consequent heart failure, with associated improvements in quality of life, haemodynamics and survival. Despite this, the benefits of pharmacotherapy are limited in the more severe cases, and mortality and morbidity remain high. The ability to replace damaged myocardium by the use of stem cell therapy offers a new and potentially exciting treatment modality, but its benefits are at present far from established. Here we briefly review the current state of cardiac stem cell therapy and consider its future.     

Pharmacodynamic properties of antiplatelet agents: current knowledge and future perspectives

Platelets play an important role in atherothrombotic disease. The currently available antiplatelet drugs target key steps of platelet activation including thromboxane A₂ synthesis, ADP-mediated signaling, and glycoprotein IIb/IIIa-mediated platelet aggregation. The improvement of our understanding on the pharmacokinetic and pharmacodynamic characteristics of these drugs enables the tailoring of the most appropriate anti-thrombotic therapy to the individual patient and risk situation in the daily clinical practice. However, current antiplatelet therapies are associated with increased bleeding risk. Thus, further research on platelet functions may give rise to numerous new antiplatelet agents with high anti-thrombotic efficiency and low adverse hemorrhagic side effects.