Clofazimine: an old drug for never-ending diseases

The anti-leprosy drug clofazimine reduces polyQ toxicity through activation of PPARγ

BACKGROUND

PolyQ diseases are autosomal dominant neurodegenerative disorders caused by the expansion of CAG repeats. While of slow progression, these diseases are ultimately fatal and lack effective therapies.

METHODS

A high-throughput chemical screen was conducted to identify drugs that lower the toxicity of a protein containing the first exon of Huntington's disease (HD) protein huntingtin (HTT) harbouring 94 glutamines (Htt-Q94). Candidate drugs were tested in a wide range of in vitro and in vivo models of polyQ toxicity.

FINDINGS

The chemical screen identified the anti-leprosy drug clofazimine as a hit, which was subsequently validated in several in vitro models. Computational analyses of transcriptional signatures revealed that the effect of clofazimine was due to the stimulation of mitochondrial biogenesis by peroxisome proliferator-activated receptor gamma (PPARγ). In agreement with this, clofazimine rescued mitochondrial dysfunction triggered by Htt-Q94 expression. Importantly, clofazimine also limited polyQ toxicity in developing zebrafish and neuron-specific worm models of polyQ disease.

INTERPRETATION

Our results support the potential of repurposing the antimicrobial drug clofazimine for the treatment of polyQ diseases.

FUNDING

A full list of funding sources can be found in the acknowledgments section.

The Dual-Targeted Fusion Inhibitor Clofazimine Binds to the S2 Segment of the SARS-CoV-2 Spike Protein

Clofazimine and Arbidol have both been reported to be effective in vitro SARS-CoV-2 fusion inhibitors. Both are promising drugs that have been repurposed for the treatment of COVID-19 and have been used in several previous and ongoing clinical trials. Small-molecule bindings to expressed constructs of the trimeric S2 segment of Spike and the full-length SARS-CoV-2 Spike protein were measured using a Surface Plasmon Resonance (SPR) binding assay. We demonstrate that Clofazimine, Toremifene, Arbidol and its derivatives bind to the S2 segment of the Spike protein. Clofazimine provided the most reliable and highest-quality SPR data for binding with S2 over the conditions explored. A molecular docking approach was used to identify the most favorable binding sites on the S2 segment in the prefusion conformation, highlighting two possible small-molecule binding sites for fusion inhibitors. Results related to molecular docking and modeling of the structure-activity relationship (SAR) of a newly reported series of Clofazimine derivatives support the proposed Clofazimine binding site on the S2 segment. When the proposed Clofazimine binding site is superimposed with other experimentally determined coronavirus structures in structure-sequence alignments, the changes in sequence and structure may rationalize the broad-spectrum antiviral activity of Clofazimine in closely related coronaviruses such as SARS-CoV, MERS, hCoV-229E, and hCoV-OC43.

Clofazimine-induced cutaneous hyperpigmentation as a source of stigma in the treatment of leprosy: A cross-sectional study

OBJECTIVES

Cutaneous hyperpigmentation is one of the main adverse effects encountered in patients undergoing leprosy treatment with multidrug therapy (WHO-MDT). This adverse effect has been described as intolerable and capable of contributing to social stigma. The objectives of this study were to quantify the variation in skin colour induced by clofazimine during and after treatment and to assess the related stigma.

METHODS

This observational cross-sectional study objectively measured skin colour in 51 patients by reading the individual typology angle (ITA°) with a spectrophotometer, followed by the application of the Stigma Scale of the Explanatory Model Interview Catalogue (EMIC).

RESULTS

Skin hyperpigmentation was observed in 100% of the individuals. They showed more negative ITA° values in lesion areas than non-lesion areas, particularly in sun-exposed regions. Clofazimine-induced cutaneous hyperpigmentation was not homogeneous and seemed to follow the lesion locations. The mean EMIC score was 18.8 points.

CONCLUSION

All patients presented skin hyperpigmentation caused by clofazimine, detectable through spectrophotometry. Hyperpigmentation strongly impacted the social domain, indicating the intersectionality of disease and skin colour stigma, contributing to the social isolation of these patients. Health authorities should consider the negative impact of clofazimine on treatment adherence.

Leprosy: treatment, prevention, immune response and gene function

Since the leprosy cases have fallen dramatically, the incidence of leprosy has remained stable over the past years, indicating that multidrug therapy seems unable to eradicate leprosy. More seriously, the emergence of rifampicin-resistant strains also affects the effectiveness of treatment. Immunoprophylaxis was mainly carried out through vaccination with the BCG but also included vaccines such as LepVax and MiP. Meanwhile, it is well known that the infection and pathogenesis largely depend on the host's genetic background and immunity, with the onset of the disease being genetically regulated. The immune process heavily influences the clinical course of the disease. However, the impact of immune processes and genetic regulation of leprosy on pathogenesis and immunological levels is largely unknown. Therefore, we summarize the latest research progress in leprosy treatment, prevention, immunity and gene function. The comprehensive research in these areas will help elucidate the pathogenesis of leprosy and provide a basis for developing leprosy elimination strategies.

Clofazimine: A journey of a drug

Among different strategies to develop novel therapies, drug repositioning (aka repurposing) aims at identifying new uses of an already approved or investigational drug. This approach has the advantages of availability of the extensive pre-existing knowledge of the drug's safety, pharmacology and toxicology, manufacturing and formulation. It provides advantages to the risk-versus-rewards trade-off as compared to the costly and time-consuming de novo drug discovery process. Clofazimine, a red-colored synthetic derivative of riminophenazines initially isolated from lichens, was first synthesized in the 1950 s, and passed through several phases of repositioning in its history as a drug. Being initially developed as an anti-tuberculosis treatment, it was repurposed for the treatment of leprosy, prior to re-repositioning for the treatment of multidrug-resistant tuberculosis and other infections. Since 1990 s, reports on the anticancer properties of clofazimine, both in vitro and in vivo, started to appear. Among the diverse mechanisms of action proposed, the activity of clofazimine as a specific inhibitor of the oncogenic Wnt signaling pathway has recently emerged as the promising targeting mechanism of the drug against breast, colon, liver, and other forms of cancer. Seventy years after the initial discovery, clofazimine's journey as a drug finding new applications continues, serving as a colorful illustration of drug repurposing in modern pharmacology.

Efficacy of clofazimine against acute and chronic Toxoplasma gondii infection in mice

Toxoplasmosis is a zoonotic protozoal disease affecting approximately one-third of the world's population. The lack of current treatment options necessitates the development of drugs with good tolerance and effectiveness on the active and cystic stages of the parasite. The present study was established to investigate, for the first time, the potential potency of clofazimine (CFZ) against acute and chronic experimental toxoplasmosis. For this purpose, the type II T. gondii (Me49 strain) was used for induction acute (20 cysts in each mouse) and chronic (10 cysts in each mouse) experimental toxoplasmosis. The mice were treated with 20 mg/kg of CFZ intraperitoneally and orally. The histopathological changes, brain cyst count, total Antioxidant Capacity (TAC), malondialdehyde (MDA) assay, and the level of INF-γ were also evaluated. In the acute toxoplasmosis, both IP and oral administration of CFZ induced a significant reduction in brain parasite burden by 90.2 and 89%, respectively, and increased the survival rate to 100% compared with 60% in untreated controls. In the chronic infection, cyst burden decreased at 85.71 and 76.18% in CFZ-treated subgroups in comparison to infected untreated controls. In addition, 87.5% and 100% of CFZ-treated subgroups survived versus untreated control 62.5%. Moreover, CFZ significantly increased INF-γ levels in acute and chronic toxoplasmosis. Tissue inflammatory lesions were considerably reduced in the CFZ-treated chronic subgroups. CFZ treatment significantly reduced MDA levels and elevated TAC in both acute and chronic infections. In conclusion, CFZ showed a promising finding regarding the ability to reduce cyst burden in acute and chronic infection. Further studies are needed to investigate the therapeutic role of CFZ on toxoplasmosis using the long-term treatment and more advanced approaches. In addition, clofazimine may need to be accompanied by another drug to augment its effect and prevent the regrowth of parasites.

Fusion assays for screening of fusion inhibitors targeting SARS-CoV-2 entry and syncytia formation

Virus fusion process is evolutionarily conserved and provides a promising pan-viral target. Cell-cell fusion leads to syncytial formation and has implications in pathogenesis, virus spread and immune evasion. Drugs that target these processes can be developed into anti-virals. Here, we have developed sensitive, rapid, adaptable fusion reporter gene assays as models for plasma membrane and alternative fusion pathways as well as syncytial fusion in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and have confirmed their specificity using neutralizing antibodies and specific protease inhibitors. The fusion report gene assays are more sensitive and unbiased than morphological fusion assay. The fusion assays can differentiate between transmembrane serine protease 2 (TMPRSS2)-dependency in TMPRSS2(+) cells and trypsin-dependency in angiotensin-converting enzyme 2 (ACE2)(+)TMPRSS2(-) cells. Moreover, we have identified putative novel fusion processes that are triggered by an acidic pH with and without trypsin. Coupled with morphological fusion criteria, we have found that syncytia formation is enhanced by TMPRSS2 or trypsin. By testing against our top drug hits previously shown to inhibit SARS-CoV-2 pseudovirus infection, we have identified several fusion inhibitors including structurally related lopsided kite-shaped molecules. Our results have important implications in the development of universal blockers and synergistic therapeutics and the small molecule inhibitors can provide important tools in elucidating the fusion process.

Mycobacterium marinum: A brief update for clinical purposes

Mycobacterium marinum (M. marinum) is a free-living, slow grower nontuberculous mycobacteria (NTM), strictly related to Mycobacterium tuberculosis, that causes disease in fresh and saltwater fish and it is one of the causes of extra-pulmonary mycobacterial infections, ranging in human from simple cutaneous lesions to disseminated forms in immunocompromised hosts. The first human cases of M. marinum infection were reported from skin lesions of swimmers in a contaminated pool, in 1951, in Sweden by Norden and Linell. Two conditions are required to develop M. marinum infection: (1) skin solution of continuity and (2) exposure to the contaminated water or direct contact with fish or shellfish. The so-called "fish-tank granuloma", the most frequent cutaneous manifestation of M. marinum infection, is characterized by a single papulonodular, verrucose and/or ulcerated granulomatous lesion in the inoculum site. Careful patient's history collection, high clinical suspicion and appropriate sample (e.g. cutaneous biopsy) for microbiological culture are crucial for a timely diagnosis. The treatment is not standardized yet and relies on administration of two active antimycobacterial agents, always guided by antimicrobial susceptibility test on culture, with macrolides and rifampin as pivotal drugs, as well as prompt surgery when feasible. In this narrative review, we provide to Clinicians an updated report of epidemiology, microbiological characteristics, clinical presentation, diagnosis, and management of M. marinum infection.

Structure-Based Optimization of Coumestan Derivatives as Polyketide Synthase 13-Thioesterase(Pks13-TE) Inhibitors with Improved hERG Profiles for Mycobacterium tuberculosis Treatment

Pks13 was identified as a key enzyme involved in the final step of mycolic acid biosynthesis. We previously identified antitubercular coumestans that targeted Pks13-TE, and these compounds exhibited high potency both in vitro and in vivo. However, lead compound 8 presented potential safety concerns because it inhibits the hERG potassium channel in electrophysiology patch-clamp assays (IC₅₀ = 0.52 μM). By comparing the Pks13-TE-compound 8 complex and the ligand-binding pocket of the hERG ion channel, fluoro-substituted and oxazine-containing coumestans were designed and synthesized. Fluoro-substituted compound 23 and oxazine-containing coumestan 32 showed excellent antitubercular activity against both drug-susceptible and drug-resistant Mtb strains (MIC = 0.0039-0.0078 μg/mL) and exhibited limited hERG inhibition (IC₅₀ ≥ 25 μM). Moreover, 32 exhibited improved metabolic stability relative to parent compound 8 while showing favorable bioavailability in mouse models via serum inhibition titration assays.

Need for a Standardized Translational Drug Development Platform: Lessons Learned from the Repurposing of Drugs for COVID-19

In the absence of drugs to treat or prevent COVID-19, drug repurposing can be a valuable strategy. Despite a substantial number of clinical trials, drug repurposing did not deliver on its promise. While success was observed with some repurposed drugs (e.g., remdesivir, dexamethasone, tocilizumab, baricitinib), others failed to show clinical efficacy. One reason is the lack of clear translational processes based on adequate preclinical profiling before clinical evaluation. Combined with limitations of existing in vitro and in vivo models, there is a need for a systematic approach to urgent antiviral drug development in the context of a global pandemic. We implemented a methodology to test repurposed and experimental drugs to generate robust preclinical evidence for further clinical development. This translational drug development platform comprises in vitro, ex vivo, and in vivo models of SARS-CoV-2, along with pharmacokinetic modeling and simulation approaches to evaluate exposure levels in plasma and target organs. Here, we provide examples of identified repurposed antiviral drugs tested within our multidisciplinary collaboration to highlight lessons learned in urgent antiviral drug development during the COVID-19 pandemic. Our data confirm the importance of assessing in vitro and in vivo potency in multiple assays to boost the translatability of pre-clinical data. The value of pharmacokinetic modeling and simulations for compound prioritization is also discussed. We advocate the need for a standardized translational drug development platform for mild-to-moderate COVID-19 to generate preclinical evidence in support of clinical trials. We propose clear prerequisites for progression of drug candidates for repurposing into clinical trials. Further research is needed to gain a deeper understanding of the scope and limitations of the presented translational drug development platform.

High Incidence of Psychiatric Disorders Associated with Cycloserine Treatment of Multidrug-Resistant Tuberculosis Patients: A Cohort Study in Beijing, China

Objective

Cycloserine (CS) is a group B anti-tuberculosis (TB) drug endorsed by the World Health Organization (WHO) for the treatment of drug-resistant (DR)-TB. Despite CS widespread acceptance and known efficacy, the high potential of drug-associated psychiatric disorders is a major concern to multidrug-resistant (MDR)-TB patients. In this study, we investigated CS-associated psychiatric disorders in a cohort of MDR-TB patients in Beijing, China. Our aim was to determine psychiatric disorder prevalence rates and associated risk factors in this population.

Methods

This MDR-TB cohort study was conducted at Beijing Chest Hospital between February 2018 and February 2021. All patients received individualized treatment regimens that included CS at some point during the full treatment course. Patient psychological status was assessed using the Symptom Checklist (SCL-90) questionnaire during the post-treatment follow-up period.

Results

Two hundred and thirty-seven MDR-TB patients were included in the final analysis. Overall, psychiatric disorders were recorded in 22 (9.28%) of the 237 patients in our cohort, with severity grades of 1 or 2 observed for the majority (8.44%) of psychiatric adverse events. As compared to results obtained for control group patients who were ≥40 years of age, patients who were <40 years of age (77.3%, 17/22) were more likely to experience psychiatric disorders [adjusted odds ratio (aOR) = 3.060; 95% CI (1.060–8.828)]. Additionally, patients with body mass index (BMI)s of <18.5 kg/m² [aOR = 3.824; 95% CI (1.502–9.739)] had significantly higher odds of being afflicted with psychiatric disorders as compared with patients with BMIs that were ≥18.5 kg/m².

Conclusion

Our results demonstrated that approximately one-tenth of Chinese MDR-TB patients experienced psychiatric disorders during CS treatment, with the majority of adverse events of moderate severity. In addition, low BMI and age <40 years were identified as independent risk factors for psychiatric disorders in MDR-TB patients receiving CS therapy.

Resistance and tolerance of Mycobacterium tuberculosis to antimicrobial agents-How M. tuberculosis can escape antibiotics

Tuberculosis (TB) poses a serious threat to public health worldwide since it was discovered. Until now, TB has been one of the top 10 causes of death from a single infectious disease globally. The treatment of active TB cases majorly relies on various anti-tuberculosis drugs. However, under the selection pressure by drugs, the continuous evolution of Mycobacterium tuberculosis (Mtb) facilitates the emergence of drug-resistant strains, further resulting in the accumulation of tubercle bacilli with multiple drug resistance, especially deadly multidrug-resistant TB and extensively drug-resistant TB. Researches on the mechanism of drug action and drug resistance of Mtb provide a new scheme for clinical management of TB patients, and prevention of drug resistance. In this review, we summarized the molecular mechanisms of drug resistance of existing anti-TB drugs to better understand the evolution of drug resistance of Mtb, which will provide more effective strategies against drug-resistant TB, and accelerate the achievement of the EndTB Strategy by 2035. This article is categorized under: Infectious Diseases > Molecular and Cellular Physiology.

Evaluating the effect of clofazimine against Mycobacterium tuberculosis when given alone or in combination with pretomanid, bedaquiline or linezolid

Clofazimine (CFZ) has been regaining prominence for treating tuberculosis in recent years. However, as a single drug, it shows limited efficacy and optimal combination partners have not been identified. Therefore, the objective of our analysis was to evaluate the efficacy of CFZ-containing two-drug regimen with pretomanid (PMD), bedaquiline (BDQ) or linezolid (LZD) by determining: i) their pharmacodynamic (PD) mode of interaction against Mycobacterium tuberculosis (Mtb) strain H37Rv in log- and acid-metabolic states, and Mtb strain 18b in a non-replicating persister metabolic state, ii) to predict bacterial cell kill of the drugs alone and in combination, and iii) to evaluate the relationship between the interaction mode and bacterial cell kill amount. The results of our Greco universal response surface analysis showed that CFZ was at least additive with a clear trend towards synergy when combined with PMD, BDQ, and LZD against Mtb in all explored metabolic states under in vitro checkerboard assay conditions. They further showed that all 2-drug combination regimens exerted more bacterial kill than any of the drugs alone. CFZ alone showed the least antimicrobial efficacy amongst the evaluated drugs and there was a lack of correlation between the mode of interaction and the amount of bacterial kill. However, we may underestimate the effect of CFZ in this screening approach due to limited in vitro study duration and neglect of target site accumulation.

Tuberculosis and pharmacological interactions: A narrative review

Even if major improvements in therapeutic regimens and treatment outcomes have been progressively achieved, tuberculosis (TB) remains the leading cause of death from a single infectious microorganism. To improve TB treatment success as well as patients' quality of life, drug-drug-interactions (DDIs) need to be wisely managed. Comprehensive knowledge of anti-TB drugs, pharmacokinetics and pharmacodynamic (PK/PD) parameters, potential patients’ changes in absorption and distribution, possible side effects and interactions, is mandatory to built effective anti-TB regimens. Optimization of treatments and adherence to international guidelines can help bend the curve of TB-related mortality and, ultimately, decrease the likelihood of treatment failure and drop-out during anti-TB treatment. Aim of this paper is to describe the most relevant DDIs between anti-TB and other drugs used in daily clinical practice, providing an updated and “easy-to-use” guide to minimize adverse effects, drop-outs and, in the long run, increase treatment success.

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Tuberculosis (TB) remains the leading cause of death from a single infectious microorganism.

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Comprehensive knowledge of anti-TB drugs and PK/PD parameters is mandatory to built effective anti-TB regimens.

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Drug-drug-interactions (DDIs) need to be avoided and/or wisely managed to ensure treatment success.

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Optimization of anti-TB treatment to avoid DDIs can help to bend the curve of TB related mortality.

Long-Term Clinical and Multimodal Imaging Findings in Patients with Disseminated Mycobacterium Chimaera Infection

Background: To analyze long-term ophthalmic clinical and multimodal imaging findings of disseminated Mycobacterium (M.) chimaera infection after cardiothoracic surgery among the Swiss Cohort. Methods: Systemic and multimodal ophthalmic imaging and clinical findings including rate of recurrence were reviewed and correlated to a previously proposed classification system of choroidal lesions and classification of ocular disease. Main Outcomes Measures: long-term clinical and multimodal ocular imaging findings of M. chimaera. Results: Twelve patients suffering from systemic infection from M. chimaera were included. Mean age at the first ophthalmic examination was 59 years (range from 48 to 66 years). Mean duration of the follow-up was 22.63 ± 17.8 months. All patients presented with bilateral chorioretinal lesions at baseline; 5 patients had additional signs, including optic disc swelling (2), choroidal neovascularization (1), retinal neovascularization (1) and cilioretinal vascular occlusion (1). Four recurrence events after discontinuation or adjustment of the antibiotic treatment were observed. Progressive choroiditis was seen in 5 patients under treatment, 4 of them deceased. Conclusions: Expertise from ophthalmologists is not only relevant but also critical for the assessment of the adverse drug effect of antimycobacterial treatment along with monitoring therapeutic response and identifying recurrences.

Treatment of Human Babesiosis: Then and Now

Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus Babesia. With its increasing incidence worldwide and the risk of human-to-human transmission through blood transfusion, babesiosis is becoming a rising public health concern. The current arsenal for the treatment of human babesiosis is limited and consists of combinations of atovaquone and azithromycin or clindamycin and quinine. These combination therapies were not designed based on biological criteria unique to Babesia parasites, but were rather repurposed based on their well-established efficacy against other apicomplexan parasites. However, these compounds are associated with mild or severe adverse events and a rapid emergence of drug resistance, thus highlighting the need for new therapeutic strategies that are specifically tailored to Babesia parasites. Herein, we review ongoing babesiosis therapeutic and management strategies and their limitations, and further review current efforts to develop new, effective, and safer therapies for the treatment of this disease.

Clofazimine functionalized polymeric nanoparticles for brain delivery in the tuberculosis treatment

Central nervous system tuberculosis (CNS-TB) is the most severe form of the disease especially due to the inability of therapeutics to cross the blood-brain barrier (BBB). Clofazimine (CFZ) stands out for presenting high in vitro activity against multi-drug resistant strains of Mycobacterium tuberculosis, however, CFZ physicochemical and pharmacokinetics properties limit drug penetration into the CNS and, consequently, its clinical use. The aim of this work was to develop polymeric nanoparticles (NPs) of poly(lactic-co-glycolic acid) (PLGA) and polyethylene glycol (PEG) loaded with CFZ and functionalized with a transferrin receptor (TfR)-binding peptide, aiming brain drug delivery for CNS-TB treatment by the intravenous route. The poor water solubility and high lipophilicity of CFZ was overcome through its entrapment into PLGA-PEG NPs manufactured by both conventional and microfluidic techniques using the nanoprecipitation principle. In vitro studies in brain endothelial hCMEC/D3 cells demonstrated that CFZ incorporation into the NPs was advantageous to reduce drug cytotoxicity. The TfR-binding peptide-functionalized NPs showed superior cell interaction and higher CFZ permeability across hCMEC/D3 cell monolayers compared to the non-functionalized NP control, thus indicating the efficacy of the functionalization strategy on providing CFZ transport through the BBB in vitro. The functionalized NPs demonstrate suitability for CFZ biological administration, suggested with low plasma protein binding, off-target biodistribution and precise delivery of CFZ towards the brain parenchyma.

Bedaquiline: Current status and future perspectives

The development of drug-resistant tuberculosis (TB) is a major threat worldwide. Based on World Health Organization (WHO) reports, it is estimated that more than 500 000 new cases of drug-resistant TB occur annually. In addition, there are alarming reports of increasing multidrug-resistant TB (MDR-TB) and the emergence of extensively drug-resistant TB (XDR-TB) from different countries of the world. Therefore, new options for TB therapy are required. Bedaquiline (BDQ), a novel anti-TB drug, has significant minimum inhibitory concentrations (MICs) both against drug-susceptible and drug-resistant TB. Moreover, BDQ was recently approved for therapy of MDR-TB. The current narrative review summarises the available data on BDQ resistance, describes its antimicrobial properties, and provides new perspectives on clinical use of this novel anti-TB agent.

A Review of Small-Molecule Inhibitors of One-Carbon Enzymes: SHMT2 and MTHFD2 in the Spotlight

Metabolic reprogramming is a key hallmark of cancer and shifts cellular metabolism to meet the demands of biomass production necessary for abnormal cell reproduction. One-carbon metabolism (1CM) contributes to many biosynthetic pathways that fuel growth and is comprised of a complex network of enzymes. Methotrexate and 5-fluorouracil were pioneering drugs in this field and are still widely used today as anticancer agents as well as for other diseases such as arthritis. Besides dihydrofolate reductase and thymidylate synthase, two other enzymes of the folate cycle arm of 1CM have not been targeted clinically: serine hydroxymethyltransferase (SHMT) and methylenetetrahydrofolate dehydrogenase (MTHFD). An increasing body of literature suggests that the mitochondrial isoforms of these enzymes (SHMT2 and MTHFD2) are clinically relevant in the context of cancer. In this review, we focused on the 1CM pathway as a target for cancer therapy and, in particular, SHMT2 and MTHFD2. The function, regulation, and clinical relevance of SHMT2 and MTHFD2 are all discussed. We expand on previous clinical studies and evaluate the prognostic significance of these critical enzymes by performing a pan-cancer analysis of patient data from the The Cancer Genome Atlas and a transcriptional coexpression network enrichment analysis. We also provide an overview of preclinical and clinical inhibitors targeting the folate pathway, the methionine cycle, and folate-dependent purine biosynthesis enzymes.

COVID-19: Antiviral Agents, Antibody Development and Traditional Chinese Medicine

The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19) is the first pandemic caused by coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, there is no effective anti-SARS-CoV-2 drug approved worldwide for treatment of patients with COVID-19. Therapeutic options in response to the COVID-19 outbreak are urgently needed. To facilitate the better and faster development of therapeutic COVID-19 drugs, we present an overview of the global promising therapeutic drugs, including repurposing existing antiviral agents, network-based pharmacology research, antibody development and traditional Chinese medicine. Among all these drugs, we focus on the most promising drugs (such as favipiravir, tocilizumab, SARS-CoV-2 convalescent plasma, hydroxychloroquine, Lianhua Qingwen, interferon beta-1a, remdesivir, etc.) that have or will enter the final stage of human testing-phase III-IV clinical trials.

Adverse drug reactions & drug interactions in MDR-TB patients

Multiple drugs taken for long duration in tuberculosis (TB) treatment, especially drug resistant TB (DR-TB), may produce adverse drug reactions (ADRs). Although any anti-TB drug can cause ADRs, but these are more common with drugs used for treatment of DR-TB. However, most of ADRs with these drugs are mild or moderate and can be managed if adequate supervision and monitoring is done. However, few ADRs can be severe or potentially life-threatening and may require removal of the offending drug(s). TB patients having comorbidities and on treatment for them may experience drug interaction with anti TB drugs and may require dose modification or change of drug. For a good TB treatment outcome patient's compliance should be ensured, and adverse events and drug interactions should be appropriately addressed by the clinicians. This article outlines the majority of the possible ADRs to anti-TB drugs used for management of DR-TB and their common drug interactions with practical recommendations to identify the possible drug(s) responsible and the most adequate management in each situation.