Biological tests of physiologically active compounds (approaches): Communication II

This review considers the methods of investigation proposed by L. A. Piruzyan in the field of preclinical trials of physiologically active compounds: (1) the search for new physiologically active compounds illustrated by analysis of the developmental mechanisms of some diseases, such as jaundice of the newborn, renal and liver insufficiency, acute drug-induced intoxication, discoid and systemic lupus erythematosus, and lupus-like syndrome; (2) experimental studies on safety of medicinal substances—the testing of substances for mutagenicity and embryotoxicity, the preparation of compounds with antimutagenic and anticarcinogenic properties, the determination of preserved blood characteristics; (3) the stabilization of medicinal preparations for use—with drug oxidation inhibitors, and substances contained in liposomes. The ligand pathology concept is presented. The necessity of an individualized approach for assessment of chemical compound safety for humans in emphasized: it should be based on the activity determination of certain enzymes in each subject. Deceased.     

The basics of preclinical drug development for neurodegenerative disease indications

Preclinical development encompasses the activities that link drug discovery in the laboratory to initiation of human clinical trials. Preclinical studies can be designed to identify a lead candidate from several hits; develop the best procedure for new drug scale-up; select the best formulation; determine the route, frequency, and duration of exposure; and ultimately support the intended clinical trial design. The details of each preclinical development package can vary, but all have some common features. Rodent and nonrodent mammalian models are used to delineate the pharmacokinetic profile and general safety, as well as to identify toxicity patterns. One or more species may be used to determine the drug's mean residence time in the body, which depends on inherent absorption, distribution, metabolism, and excretion properties. For drugs intended to treat Alzheimer's disease or other brain-targeted diseases, the ability of a drug to cross the blood brain barrier may be a key issue. Toxicology and safety studies identify potential target organs for adverse effects and define the Therapeutic Index to set the initial starting doses in clinical trials. Pivotal preclinical safety studies generally require regulatory oversight as defined by US Food and Drug Administration (FDA) Good Laboratory Practices and international guidelines, including the International Conference on Harmonisation. Concurrent preclinical development activities include developing the Clinical Plan and preparing the new drug product, including the associated documentation to meet stringent FDA Good Manufacturing Practices regulatory guidelines. A wide range of commercial and government contract options are available for investigators seeking to advance their candidate(s). Government programs such as the Small Business Innovative Research and Small Business Technology Transfer grants and the National Institutes of Health Rapid Access to Interventional Development Pilot Program provide funding and services to assist applicants in preparing the preclinical programs and documentation for their drugs. Increasingly, private foundations are also funding preclinical work. Close interaction with the FDA, including a meeting to prepare for submission of an Investigational New Drug application, is critical to ensure that the preclinical development package properly supports the planned phase I clinical trial.     

Preclinical study of the long-range safety and anti-inflammatory effects of high-dose oral meglumine

Meglumine is a methylamino derivative of sorbitol that is an approved drug excipient. Recent preclinical studies suggest that administration of high-dose oral meglumine can exert beneficial medicinal effects to treat diabetes, obesity, and fatty liver disease (NAFLD/nonalcoholic steatohepatitis [NASH]). Here we address gaps in knowledge about the pharmacology and toxicology of this substance administered at high concentrations to explore its medicinal potential. We observed that high-dose meglumine limited secretion of proinflammatory cytokines and cell adhesion molecules from activated human THP-1 or murine RAW264.7 monocytes. Preclinical pharmacokinetic analysis in Swiss mice confirmed that meglumine was orally available. Informed by this data, oral doses of 18 to 75 mM meglumine were administered ad libitum in the drinking water of Sprague-Dawley rats and two cohorts of C57BL/6 mice housed in different vivariums. In a 32-week study, urinary isoprostane levels trended lower in subjects consistent with the possibility of anti-inflammatory effects. In full lifespan studies, there was no detrimental effect on longevity. Heart function evaluated in C57BL/6 mice using an established noninvasive cardiac imaging system showed no detrimental effects on ejection fraction, fractional shortening, left ventricle function or volume, and cardiac output in mice up to 15-month old, with a potential positive trend in heart function noted in elderly mice consistent with earlier reported benefits on muscle stamina. Finally, in a transgenic model of inflammation-associated skin carcinogenesis, the incidence, number, and growth of skin tumors trended lower in subjects receiving meglumine. Overall, the evidence obtained illustrating the long-range safety of high-dose oral meglumine support the rationale for its evaluation as a low-cost modality to limit diabetes, hypertriglyceridemia, and NAFLD/NASH.     

BEBT-109, a pan-mutant-selective EGFR inhibitor with potent antitumor activity in EGFR-mutant non-small cell lung cancer

EGFR mutation-positive NSCLC tumors are highly heterogeneous, therefore, exploring an agent simultaneously targeting multiple EGFR mutations may be valuable for clinical practice. Compared with osimertinib, BEBT-109 shows more sensitive and extensive antitumor activity in EGFR mutant NSCLC, while sparing wild-type EGFR cell lines. Meanwhile, unlike the metabolite of osimertinib AZ5104, the main metabolites of BEBT-109 are found lacking in activity against wild-type EGFR cell lines. Preclinical and clinical studies demonstrate a unique pharmacokinetic profiles of BEBT-109 with rapid absorption and quick in vivo clearance without accumulation, which are conducive to minimizing the off-target toxicity of the covalent irreversible EGFR inhibitor. Oral administration of BEBT-109 induces tumor regression in EGFR exon 20 insertion xenografts, and even tumor disappearance in PC-9, HCC827 and H1975 xenograft models. Furthermore, in clinical trials, the objective responses were observed in NSCLC patients with EGFR T790M mutation in the first and second dosing cohorts. These findings demonstrate that BEBT-109, a potent pan-mutant-selective EGFR inhibitor with improved pharmacokinetic properties, might offer a promising new option for the treatment of multiple mutant-EGFR-driven NSCLC.     

The comeback of hirudin--an old-established anticoagulant agent

Early studies dating back to 1884 revealed that extracts from medicinal leeches contain a substance which is able to prevent blood from clotting. Since our successful isolation of hirudin, the pure anticoagulant substance, in the late 1950s and its characterization as a selective thrombin inhibitor with polypeptide structure, hirudin preparations have been employed for diagnostic and scientific uses in haemostaseology. As early as 25 years ago we have shown in experimental pharmacotoxicological studies that hirudin is an anticoagulant of high quality. The antithrombotic effect of hirudin was demonstrated in several thrombosis models. But the clinical use of hirudin remained limited since it was not available in adequate amounts for therapeutic purposes. One hundred years after its discovery there is a renewed interest in this naturally occurring thrombin inhibitor. Advanced methods of peptide isolation and genetic engineering are about to provide sufficient quantities of hirudin in purified form. This prompted us to resume our investigations in hirudin and to represent new experimental and clinical pharmacological studies with natural hirudin prepared from medicinal leeches and genetically engineered recombinant hirudin, thus appreciating the comeback of hirudin into the focus of interest.     

Advances in the discovery of cathepsin K inhibitors on bone resorption

Cathepsin K (Cat K), highly expressed in osteoclasts, is a cysteine protease member of the cathepsin lysosomal protease family and has been of increasing interest as a target of medicinal chemistry efforts for its role in bone matrix degradation. Inhibition of the Cat K enzyme reduces bone resorption and thus, has rendered the enzyme as an attractive target for anti-resorptive osteoporosis therapy. Over the past decades, considerable efforts have been made to design and develop highly potent, excellently selective and orally applicable Cat K inhibitors. These inhibitors are derived from synthetic compounds or natural products, some of which have passed preclinical studies and are presently in clinical trials at different stages of advancement. In this review, we briefly summarised the historic development of Cat K inhibitors and discussed the relationship between structures of inhibitors and active sites in Cat K for the purpose of guiding future development of inhibitors.     

Medicinal chemistry and therapeutic potential of CpG DNA

The observation that oligodeoxynucleotides containing CpG dinucleotides (CpG DNA) exhibit several immunological effects has led to their use as therapeutic agents and adjuvants for various diseases. Several CpG DNA drug candidates are currently being evaluated, either as monotherapies or as adjuvants (with vaccines, antibodies, antigens and allergens), in preclinical and clinical trials against cancers, viral and bacterial infections, allergies and asthma. Knowledge gained from studies of the medicinal chemistry of CpG DNA has provided a basis for designing a second generation of CpG DNA agents with desirable cytokine-inducing and potent immunomodulatory activity. This article reviews recent progress in understanding the effects of CpG DNA, the medicinal chemistry of CpG DNA, and its possible therapeutic applications.     

Spinal Cord Injury: A Review of Current Therapy, Future Treatments, and Basic Science Frontiers

The incidence of acute and chronic spinal cord injury (SCI) in the United States is more than 10,000 per year, resulting in 720 cases per million persons enduring permanent disability each year. The economic impact of SCI is estimated to be more than 4 billion dollars annually. Preclinical studies, case reports, and small clinical trials suggest that early treatment may improve neurological recovery. To date, no proven therapeutic modality exists that has demonstrated a positive effect on neurological outcome. Emerging data from recent preclinical and clinical studies offer hope for this devastating condition. This review gives an overview of current basic research and clinical studies for the treatment of SCI.     

Mesenchymal stem cell therapy in retinal and optic nerve diseases: An update of clinical trials

Retinal and optic nerve diseases are degenerative ocular pathologies which lead to irreversible visual loss. Since the advanced therapies availability, cell-based therapies offer a new all-encompassing approach. Advances in the knowledge of neuroprotection, immunomodulation and regenerative properties of mesenchymal stem cells(MSCs) have been obtained by several preclinical studies of various neurodegenerative diseases. It has provided the opportunity to perform the translation of this knowledge to prospective treatment approaches for clinical practice. Since 2008, several first steps projecting new treatment approaches, have been taken regarding the use of cell therapy in patients with neurodegenerative pathologies of optic nerve and retina. Most of the clinical trials using MSCs are in Ⅰ/Ⅱ phase, recruiting patients or ongoing, and they have as main objective the safety assessment of MSCs using various routes of administration. However, it is important to recognize that, there is still a long way to go to reach clinical trials phase Ⅲ-Ⅳ. Hence, it is necessary to continue preclinical and clinical studies to improve this new therapeutic tool. This paper reviews the latest progress of MSCs in human clinical trials for retinal and optic nerve diseases.     

Using Antifungal Pharmacodynamics to Improve Patient Outcomes

In vitro and in vivo studies of available and investigational antifungals have broadened our understanding of the pharmacodynamics of these agents as well as the pharmacokinetic/pharmacodynamic characteristics that are associated with efficacy. These data are increasingly being used as surrogate means to answer questions about dosing and administration of antimicrobial agents in order to improve outcomes in patients with invasive fungal infections, as these questions are difficult to answer in clinical trials. The objective of this article is to review the pharmacodynamic activity of widely used classes of antifungal agents, including the azoles, amphotericin B, and the echinocandins, discuss the pharmacokinetic/pharmacodynamic parameters associated with efficacy of these agents in preclinical studies, and describe how this information is being translated into the clinical arena to optimize patient outcomes.     

Reproductive and developmental toxicity of the Ginkgo biloba special extract EGb 761® in mice

Extracts from leaves of Ginkgo biloba are among the most widely used and best investigated phytopharmaceuticals worldwide. Almost all clinical trials and the majority of preclinical studies have been performed with a specifically defined extract (EGb 761^®) standardized to contain confined concentrations of active ingredients and limited quantities of potentially harmful substances. Besides pharmaceutical grade extracts poorly characterized Ginkgo preparations are now increasingly appearing on the market as nutraceuticals. While the safety of EGb 761^® has been evaluated in an extensive set of toxicology studies, adverse effects of Ginkgo extracts of non-pharmaceutical quality on reproductive functions in mice have been reported in several publications in recent years. As this species has not previously been used in reproductive toxicity studies with EGb 761^®, the present investigation was conducted to examine the influence of EGb 761^® (100, 350 and 1225 mg/kg/day) on embryo-fetal development in mice during the critical period of organogenesis. During external and internal inspection of the fetuses as well as examination of skeletal and soft tissues no embryotoxic properties were noted. In particular, the incidence of malformations, variations or retardations was not increased and the general condition of dams was not influenced. Thus, the no-observed-effect level (NOEL) was above 1225 mg/kg/day for the dams and the fetuses.     

Nitrone-based therapeutics for neurodegenerative diseases: Their use alone or in combination with lanthionines

The possibility of free radical reactions occurring in biological processes led to the development and employment of novel methods and techniques focused on determining their existence and importance in normal and pathological conditions. For this reason the use of nitrones for spin trapping free radicals became widespread in the 1970s and 1980s, when surprisingly the first evidence of their potent biological properties was noted. Since then widespread exploration and demonstration of the potent biological properties of phenyl-tert-butylnitrone (PBN) and its derivatives took place in preclinical models of septic shock and then in experimental stroke. The most extensive commercial effort made to capitalize on the potent properties of the PBN-nitrones was for acute ischemic stroke. This occurred during 1993–2006, when the 2,4-disulfonylphenyl PBN derivative, called NXY-059 in the stroke studies, was shown to be safe in humans and was taken all the way through clinical phase 3 trials and then was deemed to be ineffective. As summarized in this review, because of its excellent human safety profile, 2,4-disulfonylphenyl PBN, now called OKN-007 in the cancer studies, was tested as an anti-cancer agent in several preclinical glioma models and shown to be very effective. Based on these studies this compound is now scheduled to enter into early clinical trials for astrocytoma/glioblastoma multiforme this year. The potential use of OKN-007 in combination with neurotropic compounds such as the lanthionine ketamine esters is discussed for glioblastoma multiforme as well as for various other indications leading to dementia, such as aging, septic shock, and malaria infections. There is much more research and development activity ongoing for various indications with the nitrones, alone or in combination with other active compounds, as briefly noted in this review.     

Optimizing preclinical study design in oncology research

The current drug development pathway in oncology research has led to a large attrition rate for new drugs, in part due to a general lack of appropriate preclinical studies that are capable of accurately predicting efficacy and/or toxicity in the target population. Because of an obvious need for novel therapeutics in many types of cancer, new compounds are being investigated in human Phase I and Phase II clinical trials before a complete understanding of their toxicity and efficacy profiles is obtained. In fact, for newer targeted molecular agents that are often cytostatic in nature, the conventional preclinical evaluation used for traditional cytotoxic chemotherapies utilizing primary tumor shrinkage as an endpoint may not be appropriate. By utilizing an integrated pharmacokinetic/pharmacodynamic approach, along with proper selection of a model system, the drug development process in oncology research may be improved leading to a better understanding of the determinants of efficacy and toxicity, and ultimately fewer drugs that fail once they reach human clinical trials.     

Clinical evaluation of cellular immunotherapy in acute myeloid leukaemia

Immunotherapy is currently under active investigation as an adjuvant therapy to improve the overall survival of patients with acute myeloid leukaemia (AML) by eliminating residual leukaemic cells following standard therapy. The graft-versus-leukaemia effect observed following allogeneic haematopoietic stem cell transplantation has already demonstrated the significant role of immune cells in controlling AML, paving the way to further exploitation of this effect in optimized immunotherapy protocols. In this review, we discuss the current state of cellular immunotherapy as adjuvant therapy for AML, with a particular focus on new strategies and recently published results of preclinical and clinical studies. Therapeutic vaccines that are being tested in AML include whole tumour cells as an autologous source of multiple leukaemia-associated antigens (LAA) and autologous dendritic cells loaded with LAA as effective antigen-presenting cells. Furthermore, adoptive transfer of cytotoxic T cells or natural killer cells is under active investigation. Results from phase I and II trials are promising and support further investigation into the potential of cellular immunotherapeutic strategies to prevent or fight relapse in AML patients.     

Intranasal administration: a potential solution for cross-BBB delivering neurotrophic factors

Neurotrophic factors (NTFs) are endogenous polypeptides that regulate the growth, survival, differentiation, and functioning of neurons. The neuroprotective effects of NTFs in experimental animals give strong rationale for developing therapies for neurological disorders. However, when NTFs are applied in clinical trials, great expectation leads to equal disappointment. NTFs are large molecular-weighted and hydrophilic proteins, which limits their access to the central nervous system (CNS) after systemic administration, principally due to poor blood-brain barrier (BBB) permeability and unfavorable pharmacokinetic profiles. Although intracerebral infusion may transport NTFs into the CNS, the invasiveness limits its clinical application. Intranasal administration has been under research for decades and presents promising outcomes in preclinical studies for brain delivering of NTFs. After intranasal delivery, NTFs gain direct and quick access into the CNS at concentrations high enough to elicit their biological effects, bypassing the BBB and minimizing systemic exposure. Due to its invasiveness and convenience, intranasal delivery is feasible for NTFs administration. Although direct evidence of nose-to-brain pathway in human is lacking due to ethical problems, the existence of the nose-to-cerebral spinal fluid pathway has been verified in men. Furthermore, there is abundant indirect evidence for the nose-to-brain pathway as determined by the efficacy of intranasally administered neuroproteins, such as insulin, oxytocin, and vasopressin in clinical trials. Based on the solid preclinical research supporting the efficacy of intranasal NTFs, and the successful clinical application of neuroproteins (not NTFs), it is time to evaluate clinical application of NTFs in treating both acute and chronic CNS diseases.     

Poly(glutamic acid) for biomedical applications.

Paclitaxel is a widely used anti-cancer agent. Conjugates of paclitaxel with poly(glutamic acid) have shown great promise in preclinical trials, and clinical trials are now underway. Preclinical data suggest that more paclitaxel is preferentially delivered to tumor sites vs. nonconjugated paclitaxel. When poly(glutamic acid) is conjugated to other families of cancer drugs, similar improvements in effectiveness and reduced toxicity are observed. Optimization of poly(glutamic acid) for use in drug delivery applications is a key step in making this technology viable.     

Terminalia bellirica (Gaertn.) roxb. (Bahera) in health and disease: A systematic and comprehensive review

BackgroundTerminalia bellirica (Gaertn.) Roxb. is one of the oldest medicinal herbs of India, Pakistan, Nepal, Bangladesh and Sri Lanka as well as South-East Asia. Its medicinal utility has been described in the different traditional medicinal systems, such as Ayurveda, Unani, Siddha, and traditional Chinese medicine.PurposeThe present study is aimed at providing a comprehensive overview on the traditional medicinal use, major phytoconstituents, biological and pharmacological activities and related mechanisms of actions and clinical studies of T. bellirica. Another objective is to describe current limitations and future direction of T. bellirica-related research.MethodsPubMed, ScienceDirect, Scopus, Cochrane Library, and EBOSCO host databases were selected to explore literature published between 1980 and 2020 (till March). Keywords used in various combinations comprised of Terminalia bellirica, phytoconstituents, health effects, pharmacological activities, molecular targets, in vitro, in vivo, clinical studies, and disease prevention.ResultsA broad spectrum in vitro and in vivo studies suggested various biological and pharmacological effects, including antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, hepatoprotective, renoprotective, antidiabetic, anti-hyperlipidemic, and anticancer activities. Diverse bioactivities of T. bellirica have been ascribed to the presence of many bioactive phytochemicals, such as glucoside, tannins, gallic acid, corilagin, ellagic acid, ethyl gallate, galloyl glucose, chebulagic acid, and arjunolic acid.ConclusionPreclinical and clinical studies have suggested that T. bellirica plant and its phytoconstituents have immense potential for prevention and treatment of various diseases. Additional in vivo studies and clinical trials are warranted to realize the complete medicinal attributes of this plant.     

Green tea polyphenol epigallocatechin 3-gallate in arthritis: progress and promise

Green tea's active ingredient, epigallocatechin 3-gallate (EGCG), has gained significant attention among scientists and has been one of the leading plant-derived molecules studied for its potential health benefits. In the present review I summarize the findings from some of the most significant preclinical studies with EGCG in arthritic diseases. The review also addresses the limitations of the dose, pharmacokinetics, and bioavailability of EGCG in experimental animals and findings related to the EGCG-drug interaction. Although these findings provide scientific evidence of the anti-rheumatic activity of EGCG, further preclinical studies are warranted before phase clinical trials could be initiated with confidence for patients with joint diseases.     

Generalized nonlinear models for pharmacokinetic data

Phase I trials to study the pharmacokinetic properties of a new drug generally involve a restricted number of healthy volunteers. Because of the nature of the group involved in such studies, the appropriate distributional assumptions are not always obvious. These model assumptions include the actual distribution but also the ways in which the dispersion of responses is allowed to vary over time and the fact that small concentrations of a substance are not easily detectable and hence are left censored. We propose that a reasonably wide class of generalized nonlinear models allowing for left censoring be considered now that this is feasible with current computer power and sophisticated statistical packages. These modelling strategies are applied to a Phase I study of the drug flosequinan and its metabolite. This drug was developed for the treatment of heart failure. Because the metabolite also exhibits an active pharmacologic effect, study of both the parent drug and the metabolite is of interest.     

Antisense technology.

During the past 12 months, significant advances have been reported in the medicinal chemistry, and the pharmacodynamic and pharmacokinetic characterization of oligonucleotides. Advances in medicinal chemistry suggest that the scope for additional modifications as a means of developing therapeutic agents is substantial. This is confirmed by our clearer understanding of the pharmacodynamic and pharmacokinetic properties of oligonucleotides and the increasing number of molecular targets against which they have been shown to be active.