Targeting monocyte and macrophage subpopulations for immunotherapy: a patent review (2009 – 2013)

Introduction: Monocytes and macrophages are heterogeneous populations of effector cells in the innate immune system. Once thought to be obligatory precursors for macrophages, monocytes are now known to have several distinct sub-populations and their own independent functions. This separation of the two lineages has opened new therapeutic avenues in inflammation and created new technologies targeting the mononuclear phagocyte system (MPS).

Areas covered: A search of Google Patents and PatentScope has revealed numerous patents targeting monocytes and macrophages. This review will focus on seven patents from 2009 to 2013, utilizing autologous monocyte and macrophage adoptive transfer, genetic manipulation of the MPS, therapeutic nanoparticles and liposomes or combinations of these strategies. Patents that target monocyte recruitment are also briefly reviewed.

Expert opinion: While monocyte and macrophage targeting has yielded some promising results in animal models, these often fail to translate well to successful clinical trials. The paradigm of how cells in the MPS interact and evolve is constantly being updated, and caution must be exercised in developing immunomodulatory agents until this relationship is better understood.     

Discontinued anxiolytic drugs (2009 – 2014)

Introduction: Anxiety is a complex psychiatric disorder with an unknown aetiology and involving several neurotransmitter systems. These constraints have meant that researchers have looked to develop drugs, which target a variety of molecular targets, with the aim of creating safer and more effective anxiolytic drugs. Apart from the ‘traditional’ GABAergic and serotonergic systems, the endocannabinoid, opioidergic, glutamatergic, neurokinin, and even cholinergic systems have been (and are being) considered as preferred targets for prospective new drugs.

Areas covered: This review presents candidate drugs that were investigated for the treatment of anxiety-spectrum disorders and then discontinued between the 2009 and 2014 period.

Expert opinion: Despite the large variety of molecular targets, and the considerable financial and R&D resources dedicated to finding treatment solutions for anxiety-spectrum disorders, a great number of candidates have failed to reach the market. Indeed, there is still an unmet need for more effective anxiolytics that give patients a better quality of life. Although there are inherent problems with psychiatric drug development, it is thought that repurposed drugs may provide some benefit in the future.     

Discontinued drugs in 2012 – 2013: hepatitis C virus infection

Introduction: Hepatitis C virus (HCV) chronically infects about 150 million people worldwide. Antiviral treatment can stop and even reverse the progression of the disease. Several antivirals have been developed. However, about 10,000 compounds are tested for each drug that eventually reaches the market. It would be useful to learn from these failures, for example, by reporting the candidate drugs that were discontinued and the reason for discontinuation.

Areas covered: This article focuses on the anti-HCV drug candidates discontinued between 1 January 2012 and 1 January 2014.

Expert opinion: In detail, 17 drugs were discontinued. Of these: 10 were NS5B inhibitors, 3 were NS5A inhibitors, 2 were immunostimulants, 1 was a therapeutic and prophylactic vaccine and 1 an NS3 inhibitor. Only 3 candidates were discontinued in the preclinical phase, and 14 were discontinued during clinical development (8 in Phase II and 6 in Phase I). Most discontinuations were attributed to corporate strategic decisions. The authors believe that learning from HCV drug development failures will help pharmaceutical companies and researchers to develop better strategies for the future. It is therefore important that this information is made available.     

Aurora kinase inhibitor patents and agents in clinical testing: an update (2011 – 2013)

Introduction: Aurora kinase A, B and C, members of serine/threonine kinase family, are key regulators of mitosis. As Aurora kinases are overexpressed in many of the human cancers, small-molecule inhibitors of Aurora kinase have emerged as a possible treatment option for cancer.

Areas covered: In 2009 and 2011, the literature pertaining to Aurora kinase inhibitors and their patents was reviewed. Here, the aim is to update the information for Aurora kinase inhibitors in clinical trials and the patents filed between the years 2011 and 2013. Pubmed, Scopus®, Scifinder®, USPTO, EPO and www.clinicaltrials.gov databases were used for searching the literature and patents for Aurora kinase inhibitors.

Expert opinion: Even though both Aurora sub-type selective as well as pan-selective inhibitors show preclinical and clinical efficacy, so far no Aurora kinase inhibitor has been approved for clinical use. Particularly, dose-limiting toxicity (neutropenia) is a key issue that needs to be addressed. Preliminary evidence suggests that the use of selective Aurora A inhibitors could avoid Aurora B-mediated neutropenia in clinical settings. Also, use of adjunctive agents such as granulocyte stimulating factor to overcome neutropenia associated with Aurora B inhibition could be an answer to overcome the toxicity and bring Aurora inhibitors to market in the future.     

Aurora kinase inhibitor patents and agents in clinical testing: an update (2009 – 10)

Introduction: Mitosis is a key step in the cell cycle and is controlled by several cell cycle regulators, including aurora kinases. Aurora family members A, B and C are essential for spindle assembly, centrosome maturation, chromosomal segregation and cytokinesis. Overexpression/amplification of aurora kinases has been implicated in oncogenic transformation, including the development of chromosomal instability in cancer cells. Hence, the use of aurora kinase small molecule inhibitors as a potential molecular-targeted therapeutic intervention for cancer is being pursued by various researchers.

Area covered: This review provides an update on aurora kinase inhibitors based on developments from 2009 to 2010. The medicinal chemistry aspects of aurora kinase inhibitors, with a particular emphasis on the patent literature, are reviewed. Databases such as PubMed, SCOPUS, Scifinder and www.clinicaltrials.gov database were used to search for literature in the preparation of this review.

Expert opinion: Around a dozen aurora kinase inhibitors are currently undergoing various Phase I – II evaluations for different human cancers. Instead of being applied as a monotherapy, combinations of aurora kinase inhibitors and existing chemotherapeutic compounds seem to give better therapeutic outcomes and are, therefore, a promising future cancer therapy.     

Glycosidase inhibitors: a patent review (2008 – 2013)

Introduction: In the recent decades, the interest on glycosidases has dramatically increased, mainly because these enzymes play a key role in many biological processes. The importance of these enzymes is also reflected by a number of diseases, which result from the lack or dysfunction of a given glycosidase, as well as by the use of glycosidase inhibitors in the treatment of metabolic disorders or viral infections. Based on the biological potential associated to these enzymes, several glycosidase inhibitors have been developed. In this review, the most important inhibitors targeting these enzymes, including the disaccharides, iminosugars, carbasugars, thiosugars and other non-glycosidic compounds will be discussed and special attention will be given to the ones that are currently used clinically.

Areas covered: This review summarizes and characterizes the current knowledge regarding the classes of glycosidase inhibitors that have therapeutic potential in a wide range of diseases. It highlights the relevant research, patents and patent applications filed in the past years on the field.

Expert opinion: Since the glycosidase inhibitors are involved in several chronic diseases and possibly pandemic, the pharmaceutical research toward developing new generations of these molecules is very important to public health in the world. The unique combination of these compounds – for example, they share many properties with natural carbohydrates and also possess distinct specific characteristics – makes them precious for pharmaceutical companies in an attempt to search for potential new drugs. Currently, the most promising compounds are the iminosugars and thiosugars due to their better oral bioavailability.     

An update on anti-allergic patents granted in China: 2009 – 2011

Introduction: The prevalence of allergic diseases has increased dramatically in recent decades. Therefore, there is a pressing need for the development of effective anti-allergic services worldwide.

Areas covered: In previous studies, the authors had analyzed a total of 789 anti-allergic patents granted in China from 1988 to 2008. Herein, they report a further 151 anti-allergic patents issued in China during 2009 – 2011. The current analysis covers the scientific progress in supporting anti-allergic patent applications and granted patent literature, in China, for the last 3 years.

Expert opinion: The 151 anti-allergic patents granted from 2009 to 2011 mainly focus on seven types of products. They are: traditional Chinese medicines (TCM), plant extracts, biological products, synthetic compounds, pharmaceutical preparations, medical apparatus and new treatment modalities. Although the overall number of anti-allergic patent applications made between 2009 and 2011 in China is less than that of the USA and Europe, patents on TCM have increased. This suggests that there are demands for modernization of TCMs. Recently, studies of interesting new immunomodulators have also been conducted, and some of these are likely to represent clinically useful advances. In the last 3 years, several patents on these novel potential drugs have also been granted in China. The large number of anti-allergic patents issued in China, in recent times, suggests that the Chinese market is relatively competitive one that will help pharmaceutical companies make proper decisions for their research and development strategies.     

Antifolate agents: a patent review (2010 – 2013)

Introduction: The folate biosynthetic pathway, responsible for the de novo synthesis of thymidine and other key cellular components, is essential in all life forms and is especially critical in rapidly proliferating cells. As such, druggable targets along this pathway offer opportunities to impact many disease states such as cancer, infectious disease and autoimmune disease. In this article, recent progress on the development of antifolate compounds is reviewed.

Areas covered: The evaluation of the patent literature during the period 2010 – 2013 focused on any compounds inhibiting recognized targets on the folate biosynthetic pathway.

Expert opinion: The folate pathway constitutes a well-validated and well-characterized set of targets; this pathway continues to elicit considerable enthusiasm for new drug discovery from both academic and industrial pharmaceutical research groups. Within the pathway, the enzymes dihydrofolate reductase and thymidylate synthase persist as the most attractive targets for new drug discovery for the treatment of cancer and infectious disease. Importantly, new potential targets for antifolates such as those on the purine biosynthetic pathway have been recently explored. The use of structure-based drug design is a major aspect in modern approaches to these drug targets.     

Resveratrol derivatives: a patent review (2009 – 2012)

Introduction: There is currently a wealth of information on the effects of resveratrol and its derivatives in therapeutic, cosmetic and nutraceutical patent applications. Structure–activity studies of the resveratrol scaffold provide a foundation for the development of new analogs with potent activity or other beneficial properties. Ongoing research has yielded promising results and potential use in the treatment of various diseases.

Areas covered: This review provides analysis of patents published from January 2009 to April 2013. There is a focus on different approaches for the production of resveratrol derivatives, combinations of new derivatives with old drugs, and applications in therapeutic areas, nutraceutical compositions and cosmetics.

Expert opinion: The ability of resveratrol to interact with a disparate array of subcellular targets is uncanny. Nonetheless, even though limited or no toxicity is apparent, the molecule is not a panacea due to lack of potency and issues with bioavailability. Thus, as witnessed by a number of patents, a large assortment of derivatives have been synthesized under the guise of having superior characteristics for treating or preventing various diseases or for use as neutraceutics and cosmetics. Some of these suppositions are probably correct, but evidence-based applications are essentially nil due to a lack of commitment in terms of investing the resources necessary for the conduct of obligatory clinical trials. Current usage is largely based on anecdotes and publicity. Hopefully, at some point in time, it will be possible to follow a standard protocol with a predicable outcome.     

Acridine derivatives: a patent review (2009 – 2010)

Introduction: Acridines are highly important heterocyclic compounds with immense biological significance as they act as the central core of antitumor, anti-protozoan, antiviral and multi-drug resistance modulating agents. The tricyclic aromatic structure of acridine is primarily responsible for its intercalation with DNA by controlling its biological profile and the substitution pattern of the molecule, which leads to several other applications.

Areas covered: In this review, acridine-based functional molecules and patents of acridine derivatives filed from 2009 to 2010 are discussed. The latest information about the medical importance of new acridine-based molecules is also discussed (e.g., materials with sensing and electrical/thermal properties).

Expert opinion: The tricyclic aromatic heterocyclic structure of acridine has a lot of potential for biological and material utilization. The versatility of fluorescent acridines could be further enhanced by introducing amino-acid chains or other polar substituents on the central moiety, which due to increased water solubility could increase their effectiveness under physiological conditions.     

Matrix metalloproteinase inhibitors: a patent review (2011 – 2013)

Introduction: The MMPs are involved in tissue remodeling. An imbalance between the inhibition and activation of MMPs results in excessive degradation of the extracellular matrix, which leads to some diseases including cancer, rheumatoid arthritis, osteoarthritis, heart disease and neurodegenerative diseases such as stroke. In this review, recent advances in the research of MMP inhibitors are reviewed.

Areas covered: This updated review summarized new patents on MMP inhibitors within January 2011 – December 2013.

Expert opinion: This review gives the latest development in the area of MMP inhibitors, which aim to treat disease processes associated with the MMPs. Structure-based design techniques have been used successfully in the search of selective MMP inhibitors, and these inhibitors can also be derived from natural products. Furthermore, imaging ‘in vivo’ technologies have been developed in order to follow the drug distribution to the targeted tissues, and to quantify the drug efficiency.     

Antiplasmodial drug targets: a patent review (2000 – 2013)

Introduction: New antimalarials with novel modes of action are crucial in countering the challenge of emerging drug-resistant Plasmodium falciparum. Equally significant is the identification and characterization of the targets these compounds inhibit. Biochemical evidence from seminal studies, whole genome clues and high-throughput chemical screening data provide starting points worth exploring in target identification efforts. Several proteins and biochemical processes/pathways critical to parasite survival have since been profiled and patented.

Areas covered: In this review, an analysis of patents describing the characterization of different enzymatic and/or biosynthetic targets in P. falciparum over the last fourteen years is presented. The review also details structures, biological evaluation, potential modes of action and therapeutic utilities of small molecule antiplasmodial compounds from ongoing research, designed to inhibit these targets.

Expert opinion: Though various strategies to address antimalarial drug resistance exist, direct inhibition of unrelated targets and non-genome coded processes potentially present the most effective options. Additionally, interest in peptides as antimalarials merits further exploration especially in view of their unique low susceptibility to resistance, wider spectrum of action and faster activity. Finally, target-based optimization and chemical validation of novel targets can be facilitated by routine phenotypic whole-cell screening of antiplasmodial hits against any new target(s).     

Glycemic control in diabetic patients in King Khalid University Hospital (KKUH) – Riyadh – Saudi Arabia

Objectives

To evaluate glycemic control of diabetic patients at the King Khalid University Hospital (KKUH) in Riyadh, Saudi Arabia.

Methods

A cross sectional study was conducted among diabetic patients attending KKUH, Riyadh. Patients were identified through the hospital pharmacy records, over a one year period (January–December, 2009). A total of 20,000 patients were identified, and 1520 patients were selected by a simple random method. Medical charts were reviewed, the data were collected in a specially designed data sheet: and entered in a computer, and finally analyzed using a SPSS program.

Results

About 90% of patients were older than 40 years old and 90% were overweight or obese. Fasting blood sugar was above 7.2 mmol/L in 60% of the patients and random blood sugar was more than 10 mmol/L in about 70% of patients. The overall glycemic control as evaluated by HBA1C was acceptable in about 40% of the patients. Cholesterol level was normal in more than 70% of patients while triglyceride was normal in 56% of patients. In about half of the patients systolic blood pressure was not controlled, while in 27% the diastolic blood pressure was above the target level.

Conclusion

The control of diabetes and its associated cardiovascular risk factors in this hospital – based survey, in Riyadh is far from optimal. Further studies are needed to find out the possible causes for this defective care of diabetic patients.     

1,2-Benzisoxazole compounds: a patent review (2009 – 2014)

Introduction: Benzisoxazoles represent a class of heterocyclic compounds of great importance for the preparation of biologically active compounds. Benzisoxazoles are an important structure and some benzisoxazole-based medicines have been approved for human clinical use, including atypical antipsychotics (risperidone, paliperidone and iloperidone) and an anticonvulsant (zonisamide).

Areas covered: This review puts emphasis on the recent progress in therapeutically attractive benzisoxazole derivatives especially 1,2-benzisoxazoles, which were published in the patent literature between 2009 and 2014. As for the class of medicines, the main focus is on atypical antipsychotics and potential therapeutic treatments for other CNS disorders. This review also covers the examples of benzisoxazole-based kinase inhibitors. Moreover, novel benzisoxazoles with significant therapeutic interest are also mentioned.

Expert opinion: More recent examples of structural modification of existing drugs led to the discovery of some promising benzisoxazoles for antipsychotic use. The design of multi-target ligands is important for the manipulation of pharmacological properties and safety profiles for the use of antipsychotics. Benzisoxazoles have been widely used as pharmacophores in the search for novel drug candidates in a variety of therapeutic area. It is fair to assume that the wide and frequent use of benzisoxazoles in drug discovery and development will continue into the future.     

Inhibitors of melanogenesis: a patent review (2009 – 2014)

Introduction: Melanogenesis is the process of producing the melanin pigment, in which a series of chemical and enzymatic pathways are involved. Modulation at any level of this process would become an important approach in the treatment of hyper- or hypopigmentation-related diseases. Since hyperpigmentation covers important issue in cosmetics, there is a need of such review to understand and update this field to the public domain.

Areas covered: In this review, authors discuss most recent melanogenesis inhibitors published in the patents since 2009. The up-to-date overview of classical catechol-based tyrosinase inhibitors to non-classical melanogenesis inhibitors with different mechanism of action is discussed. Inhibitors including small-interfering RNA and peptides from ～ 30 patents and their associated literature are also discussed.

Expert opinion: Although a huge number of melanogenesis inhibitors have been reported, the future studies should be focused towards the identification of new inhibitors with a clear mechanism. The next breakthrough in the field therefore, is likely to come from the detailed structure–activity relationship studies of thioureas with improved therapeutic profiles. Targeting other parameters such as number or size of melanosomes, maturation of melanosomes and expression of melanogenic enzymes may give the best results to overcome toxicity and other formulation problems.     

Hedgehog pathway inhibitors: a patent review (2009 – present)

Introduction: The hedgehog (Hh) pathway is a developmental signaling pathway that plays a key role in directing cellular growth and tissue patterning during embryonic development. Dysregulation of Hh signaling has been linked to the development of a variety of human tumors, and numerous drug development programs in both academia and industry are actively exploring inhibitors of the pathway as anti-cancer agents.

Areas covered: This review surveys the recent patent literature (2009 – 2012) for Hh pathway inhibitors as treatments for a variety of human malignancies.

Expert opinion: To date, all of the pathway inhibitors that have entered clinical trials and the majority of compounds identified via high-throughput screens target smoothened (Smo), a transmembrane protein that is essential for pathway signaling. While these compounds have shown initial promise in preclinical and clinical trials, several mechanisms of resistance to Smo inhibitors have been identified. Even with this knowledge, the majority of small-molecule pathway inhibitors disclosed in the recent patent literature directly target Smo. The continued identification of Hh pathway inhibitors that function either upstream or downstream is warranted not only to combat these emerging resistance mechanisms, but also to help elucidate the various cellular mechanisms that control both normal and oncogenic pathway signaling.     

p38 MAPK inhibitors: a patent review (2012 – 2013)

Introduction: The p38 MAPK is a ubiquitous target in the research-based pharmaceutical industry. It plays a decisive role in the regulation of the production of proinflammatory cytokines. Since novel biological therapies have revolutionized the treatment of chronic inflammatory diseases, an intensive global search is underway for small molecules for the same application.

Areas covered: Herein, the patents and the corresponding publications of international companies, which focus on the development and identification of a new generation of small-molecule p38 inhibitors, are summarized.

Expert opinion: The most promising approach is the development of linear binders, which induce a glycine flip at Gly110 of the kinase hinge region by a carbonyl oxygen atom of the respective ligand. The major focus of the patent works was the application of molecules in new indications. Previous applications were in the treatment of rheumatoid arthritis; currently, there are several new applications, including pulmonary diseases, cancer and Alzheimer's disease. Targeting p38 upstream kinases and downstream effectors has also proved to be a very promising step in the development of more effective inhibitors. A further trend is drug combination, applied to a wide range of indications, such as chronic obstructive pulmonary disease and cancer.     

New substituted benzimidazole derivatives: a patent review (2013 – 2014)

Introduction: The benzimidazole nucleus is found in a variety of naturally occurring compounds and is of significant importance in medicinal chemistry. Owing to its conspicuous pharmacological properties, benzimidazoles have become an important pharmacophore and sub-structure in drug design and have been screened for a wide range of biological activities.

Areas covered: Areas covered in this paper include a review of the biological effects, mechanisms and synthesis of benzimidazole derivatives in the past 2 years based on patents. The patent databases Scifinder and esp@cenet were used to locate patent applications that were published between 2013 to present. Information from articles published is also included.

Expert opinion: Benzimidazole derivatives are remarkably effective compounds to many diseases and may have the potential to be the first effective therapy against Ebola virus. Therefore, it is of great importance to develop specific design software and sustainable industrial synthetic routes for the development of effective and clinically relevant benzimidazole compounds.     

Recent updates in utilizing prodrugs in drug delivery (2013–2015)

ABSTRACT

Introduction: Utilizing the prodrug approach as a method to overcome various pharmaceutical and pharmacokinetic barriers to drug delivery is significantly accelerating and achieving successes. In contrast to the older traditional prodrugs which suffer from decreased bioavailability and a high profile of side effects, due to activation at undesired sites, the targeted prodrug approach utilizes delivery systems to improve delivery for a wide range of therapeutics including anti-cancer, anti-bacterial and anti-inflammatory drugs.

Areas covered: Recent updates in utilization of prodrugs in drug delivery between 2013 and 2015 are discussed. Targeted prodrugs against cancer, solid tumors, microbial infections, inflammation and other diseases using advanced delivery systems such as theranostic approaches, siRNA, DOX immunoconjugate, C 60-ser carrier vector, biotinylated prodrug, human serum albumin (HSA) carrier and others are presented.

Expert opinion: Recent research efforts have been directed at developing targeted prodrugs to replace the classical prodrugs. The use of this approach has accelerated following the emergence of encouraging results from several studies on targeted prodrugs that have highlighted their higher efficiency and improved safety profiles.

Targeted prodrug delivery is now considered more than a chemical modification method. It is an applicable and promising approach and, in the future, better knowledge and wide application of this approach may be attained which may pave the way for more forward-thinking and creative techniques.     

Betulinic acid and its derivatives: a patent review (2008 – 2013)

Introduction: Betulinic acid (BA) is a triterpenoid that can be obtained from renewable resources. BA is cytotoxic to many human tumor cell lines mainly by apoptosis but cell death might also be triggered by nonapoptotic pathways. Many derivatives have been synthesized to improve the very weak solubility of parent BA and to increase its cytotoxicity as well as its selectivity toward tumor cells.

Areas covered: A brief introduction into cancer is given reflecting the different pathways this disease might be treated using chemotherapy using natural product analogs especially triterpenes. The different ways of action of BA in cancer cells are discussed. Finally, this review describes the main synthetic modifications that have been performed and discusses, in short, the structure–activity relationships of these analogs, investigated between 2008 and 2013 including some important publications from early 2014.

Expert opinion: A number of patents on BA analogs for the chemotherapy of cancer have been reported between 2008 and 2013. Most of these patents deal with modifications at positions C-3, C-20 and C-28. There are only a few compounds meeting the needs of a sufficient hydrosolubility, while retaining high cytotoxicity and selectivity toward tumor cells. Thus, one might expect that there will be some efforts in developing molecules of improved solubility and to find new and more efficient forms of administration (liposomes, transdermal application and nanoemulsions). An important sideline might be the treatment of the age-dependent degeneration of the macula, a possible caveat of which might be a certain degree of CNS toxicity associated with several derivatives of BA.