Clofazimine as a comparator for preclinical efficacy evaluations of experimental therapeutics against pulmonary M. abscessus infection in mice.

Mycobacteroides abscessus (Mab, also known as Mycobacterium abscessus) can cause chronic pulmonary disease in the setting of structural lung conditions. Current treatment recommendations require at least one year of daily therapy with repurposed antibiotics. Yet these therapies are often ineffective and associated with significant adverse events. To address this challenge, research efforts are underway to develop new antibiotics and regimens. During the preclinical phase of treatment development, experimental agents require testing and comparison alongside positive controls that are known agents with clinical history. As there are no FDA approved treatments for this indication, here, we have considered repurposed antibiotics currently included in the recommendation for treating Mab disease as candidates for selection of an ideal standard comparator that can serve as a positive control in preclinical studies. Clofazimine meets the criteria for an ideal positive control as it can be administered via the least invasive route, requires only once-daily dosing, is well tolerated, and is widely available in high purity from independent sources. Using a mouse model of pulmonary Mab disease, we assessed for ideal dosages of clofazimine in C3HeB/FeJ and BALB/c mice in a six-week treatment window. Clofazimine, 25 mg/kg, once daily, produced desired reduction in Mab burden in the lungs of C3HeB/FeJ and BALB/c mice. Based on these findings, we conclude that clofazimine meets the criteria for a positive control comparator in mice for use in preclinical efficacy assessments of agents for treatment of Mab pulmonary disease. Although not included in the current standard-of-care for treating Mab disease, rifabutin, 20 mg/kg, also produced desired reduction in Mab lung burden in C3HeB/FeJ mice but not in BALB/c mice. IMPORTANCE: Mycobacteroides abscessus can cause life-threatening infections in patients with chronic lung conditions. New treatments are needed as cure rate using existing drugs is low. During pre-clinical phase of treatment development, it is important to compare the efficacy of the experimental drug against existing ones with known history. Here, we demonstrate that clofazimine, one of the antibiotics repurposed for treating Mab disease, can serve as a positive control comparator for efficacy assessments of experimental drugs and regimens to treat M. abscessus disease in mice.

Effectiveness of Shorter Treatment Regimen in Multidrug-Resistant Tuberculosis Patients in Pakistan: A Multicenter Retrospective Record Review.

In Pakistan, the treatment of multidrug-resistant tuberculosis (MDR-TB) with a shorter treatment regimen (STR), that is, 4-6 months of amikacin, moxifloxacin (Mfx), ethionamide, clofazimine (Cfz), pyrazinamide (Z), ethambutol (E), and high-dose isoniazid, followed by 5 months of Mfx, Cfz, Z, and E, was initiated in 2018. However, there is a lack of information about its effectiveness in Pakistani healthcare settings. Therefore, this retrospective record review of MDR-TB patients treated with STR at eight treatment sites in Pakistan aimed to fill this gap. Data were analyzed using SPSS 23. Multivariate binary logistic regression (MVBLR) analysis was conducted to find factors associated with death and treatment failure, and lost to follow-up (LTFU). A P-value < 0.05 was considered statistically significant. Of 912 MDR-TB patients enrolled at the study sites, only 313 (34.3%) eligible patients were treated with STR and included in the current study. Of them, a total of 250 (79.9%) were cured, 12 (3.8%) completed treated, 31 (9.9%) died, 16 (5.1%) were LTFU, and four (1.3%) were declared as treatment failures. The overall treatment success rate was 83.7%. In MVBLR analysis, patients' age of 41-60 (odds ratio [OR] = 4.9, P-value = 0.020) and > 60 years (OR = 3.6, P-value = 0.035), being underweight (OR = 2.7, P-value = 0.042), and previous TB treatment (OR = 0.4, P-value = 0.042) had statistically significant association with death and treatment failure, whereas patients' age of > 60 years (OR = 5.4, P-value = 0.040) and previous TB treatment (OR = 0.2, P-value = 0.008) had statistically significant association with LTFU. The treatment success rate of STR was encouraging. However, to further improve the treatment outcomes, special attention should be paid to the patients with identified risk factors.

Efficacy of linezolid on Treponema pallidum, the syphilis agent: A preclinical study.

BACKGROUND: Penicillin G, the current standard treatment for syphilis, has important drawbacks, but virtually no preclinical or clinical studies have been performed to identify viable alternatives. We tested, both in vitro and in vivo, three marketed antibiotics with adequate pharmacological properties to treat syphilis. METHODS: We used an in vitro culturing system of T. pallidum to perform drug susceptibility testing and applied quantitative PCR targeting the tp0574 gene to measure bacterial growth. To confirm in vivo efficacy, fifteen rabbits were infected intradermally with T. pallidum at eight sites each and randomly allocated to an experimental treatment (linezolid, moxifloxacin, clofazimine) or a control arm (benzathine penicillin G [BPG], untreated). The primary outcome was treatment efficacy defined as the time to lesion healing measured from the date of treatment start. Secondary outcomes were absence of treponemes or treponemal mRNA in injection sites, absence of seroconversion, and cerebrospinal fluid (CSF) abnormalities and negative rabbit infectivity tests (RIT). FINDINGS: Linezolid showed in vitro bactericidal activity at concentrations of 0.5 µg/mL or higher. When administered orally to experimentally infected rabbits, it induced healing of early lesions at a time similar to BPG (hazard ratio 3.84; 95% CI 2.05-7.17; p < 0.0001 compared to untreated controls). In linezolid-treated animals, dark-field microscopy and qPCR assessment showed no presence of treponemes after day 3 post-treatment start, serologic test did not convert to positive, CSF had no abnormalities, and RIT was negative. Moxifloxacin and clofazimine failed to inhibit bacterial growth in vitro and could not cure the infection in the rabbit model. INTERPRETATION: Linezolid, a low-cost oxazolidinone, has in vitro and in vivo activity against T. pallidum, with efficacy similar to BPG in treating treponemal lesions in the animal model. Our findings warrant further research to assess the efficacy of linezolid as an alternative to penicillin G to treat syphilis in human clinical trials. FUNDING: European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant agreement No. 850450).

Acquisition of clofazimine resistance following bedaquiline treatment for multidrug-resistant tuberculosis.

OBJECTIVES: We described the prevalence of clofazimine (CFZ) resistance in a multidrug-resistant tuberculosis (MDR-TB) cohort in China. We also aimed to identify dynamic changes in CFZ susceptibility and its molecular mechanism after exposure to bedaquiline (BDQ) and/or CFZ. METHODS: The experimental settings were conducted based on our MDR-TB cohort receiving BDQ-containing regimens. Sequential isolates were obtained from patients. CFZ and BDQ susceptibility of isolates were determined using the minimum inhibitory concentration (MIC) method. The fragments of Rv0678 and pepQ were sequenced. RESULTS: A total of 277 patients infected with MDR-TB were included in our study. CFZ resistance was noted in 23 (23/277, 8.3%) isolates. The rate of acquired CFZ resistance (12/189, 6.3%) was significantly greater than that of primary resistance (11/88, 12.5%, P = 0.028). Out of 23 CFZ-resistant isolates, five (5/23) were BDQ-resistant, and the other 18 (18/23) were susceptible to BDQ. Of note, nine 9/23) out of 23 CFZ-resistant isolates had mutations within either target genes. Kaplan-Meier analysis demonstrated that the baseline CFZ resistance had no influence on time to culture conversion in our cohort (P = 0.828). Acquired CFZ resistance emerged in eight (8/94, 8.5%) patients during treatment for MDR-TB, including three patients receiving regimens without CFZ. CONCLUSIONS: Our results demonstrate the high rate of CFZ resistance among MDR-TB patients in China. Patients treated with BDQ-containing regimens achieve comparative culture conversion rate regardless of baseline CFZ susceptibility. The presence of acquired CFZ-resistance following BDQ treatment without known mutation indicates that other mechanisms conferring cross resistance to these two compounds may exist.

Minimal Inhibitory Concentration of Clofazimine Among Clinical Isolates of Nontuberculous Mycobacteria and Its Impact on Treatment Outcome.

BACKGROUND: Clofazimine has been regarded as a promising agent for the treatment of nontuberculous mycobacteria pulmonary disease (NTM-PD). However, its overall effectiveness in vitro and in the clinic remains unknown. RESEARCH QUESTION: What is the minimal inhibitory concentration (MIC) of clofazimine in clinical isolates and the association between MICs and treatment outcome? STUDY DESIGN AND METHODS: MICs for clofazimine were measured in clinical isolates from NTM-PD patients who participated in a prospective study at Seoul National University Hospital. The MIC was determined by using the broth microdilution concentration method. Correlation between MIC and conversion to negative of sputum culture with clofazimine was determined. RESULTS: Of a total 189 isolates, 133 strains were Mycobacterium avium complex (MAC) and 40 strains were M abscessus. Although the clofazimine MICs for MAC ranged from 0.031 mg/L to 8 mg/L, the values obtained for M abscessus ranged from 0.031 mg/L to 16 mg/L. Of 20 patients who were treated with a regimen including clofazimine, eight achieved negative conversion of sputum culture. All patients with isolates exhibiting clofazimine MIC values ≤ 0.25 mg/L achieved culture conversion. The likelihood of culture conversion in patients with MIC value ≤ 0.25 mg/L was much higher than that of patients with MIC value > 0.5 mg/L (OR, 39.3; P = .021). INTERPRETATION: The MICs of clofazimine varied widely in clinical isolates from patients with NTM-PD. Negative conversion of sputum culture with clofazimine use was associated with a lower MIC value. Clofazimine use could be considered in patients with NTM-PD when the MIC value is ≤ 0.25 mg/L. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01616745; URL: www.clinicaltrials.gov.

Bedaquilina para pacientes com tuberculose resistentes à rifampicina, multirresistentes e extensivamente resistentes a medicamentos / Bedaquiline for tuberculosis-resistant patients rifampicin, multi-resistant and extensively resistant to medicines

INTRODUÇÃO: A tuberculose (TB), conhecida anteriormente como tísica, é uma doença que pode ser causada por sete espécies do gênero do complexo Mycobacterium sendo a mais importante, do ponto de vista de saúde pública, a M. tuberculosis. Globalmente cerca de 10 milhões de pessoas tiveram TB no ano de 2018. No Brasil, em 2018, foram diagnosticados 72.788 casos novos de TB o que representa uma incidência de 34,8 casos por 100 mil habitantes. A TB pode ser classificada como pulmonar e extrapulmonar, sendo a primeira forma mais prevalente. Além disso, a TB pode ser classificada conforme a resistência à medicamentos, tais como: RR-TB, MDR-TB e XDR-TB. PERGUNTA DE PESQUISA: A bedaquilina (BDQ) associada ao tratamento padrão para pacientes adultos com RR-TB, MDR-TB ou XDR-TB, é mais eficaz, efetiva e segura comparado ao tratamento padrão utilizado pelo SUS (levofloxacino, moxifloxacino, amicacina, capreomicina, etionamida, terizidona, linezolida, clofazimina, pirazinamida, etambutol, isoniazida, rifampicina e paraminossalicílico) ou placebo? TECNOLOGIA: Bedaquilina (Sirturo®). EVIDÊNCIAS CIENTÍFICAS: A revisão sistematizada recuperou nove estudos (uma revisão sistemática [RS] com meta-análise em rede [network meta-analysis - NMA], um ensaio clínico randomizado [ECR] com dois relatos e sete estudos de coorte [seis retrospectivas e uma prospectiva]). A RS, com NMA, avaliou a BDQ em comparação aos medicamentos delamanida, metronidazol, moxifloxacino e levofloxacino. A RS avaliou os desfechos conversão de cultura do escarro e aceitabilidade, e não foram verificados resultados estatisticamente significantes. Os estudos de coorte avaliaram a BDQ em comparação aos mais diversos tratamentos disponíveis para RR-TB, MDR-TB e XDR-TB. As coortes avaliaram os seguintes desfechos: sobrevida sucesso no tratamento, tratamento completo, cura, conversão da cultura do escarro e mortalidade. Os resultados não foram estatisticamente significantes na meta-análise de modelo de efeitos randomizados para todos os desfechos avaliados, porém os resultados dos efeitos fixos demostraram resultados estatisticamente significantes favorecendo o tratamento com BDQ em comparação ao tratamento sem BDQ. Vale salientar que foram realizadas análises de subgrupos com o ECR, TMC207, que avaliou eficácia e segurança da BDQ associado ao tratamento padrão em comparação ao grupo placebo associado ao tratamento padrão em até 120 semanas para os desfechos de conversão da cultura do escarro, cura e segurança (mortalidade), porém não mudaram a direção dos resultados nas duas modelagem da meta-análise. AVALIAÇÃO ECONÔMICA (AE): Os tratamentos com BDQ comparado aos tratamentos do SUS mostraram-se dominados na avaliação de custo-efetividade, para o desfecho paciente curado. Assim, os tratamentos do SUS para RR-TB, MDR-TB e XDR-TB dominaram todos os tratamentos com BDQ, ou seja, todos os tratamentos com BDQ foram menos efetivos e mais caros que os tratamentos do SUS para obter a cura dos indivíduos com RR-TB, MDR-TB e XDR-TB. AVALIAÇÃO DE IMPACTO ORÇAMENTÁRIO (AIO): A AIO, para os pacientes com RR-TB, variou entre um custo incremental R$ 936 mil no caso base a uma economia de -R$ 1 milhão ao final do quinto ano no cenário alternativo; para MDR-TB variou entre uma economia de -R$44 mil no caso base a um gasto de R$ 110 mil ao final do quinto ano no cenário alternativo; e para XDR-TB variou entre um custo incremental de R$ 188 mil no caso base a R$ 4 mil no cenário alternativo ao final do quinto ano. MONITORAMENTO DO HORIZONTE TECNOLÓGICO (MHT): Cinco medicamentos foram detectados no MHT para pacientes com MDR-TB e XDR-TB (canamicina, cicloserina, sutezolida, pretomanide e protionamida). CONSIDERAÇÕES FINAIS: Há resultados conflitantes nas evidências encontradas no relatório. O ECR, analisado como de alto risco de viés (Risk of Bias 2.0) mostrou que a BDQ associada ao tratamento padrão é eficaz em comparação ao grupo de tratamento placebo associado ao tratamento padrão, porém com maior número de mortes e episódios de náusea em comparação ao grupo de tratamento sem a BDQ. Os resultados da RS, com NMA, de qualidade moderada, não demonstraram diferenças estatisticamente significantes entre as tecnologias avaliadas. Os resultados das meta-análises dos estudos de coorte de baixa qualidade metodológica (Newcastle-Ottawa Scale), em combinação com o ECR da BDQ, foram demonstrados em efeitos fixos e randomizados. Os desfechos sucesso no tratamento, tratamento completo, cura, conversão da cultura do escarro e mortalidade não foram estatisticamente significantes no modelo de efeito randomizados na meta-análise. No entanto, foram estatisticamente significantes no modelo de efeito fixos da metaanálise, e favoreceram o tratamento com BDQ em comparação aos pacientes não tratados sem BDQ. A AE demonstrou que os tratamentos com BDQ foram dominados em relação aos tratamentos disponibilizados no SUS sem BDQ, para o desfecho paciente tratado, sendo, portanto, mais custosos e menos efetivos. A AIO, para pacientes com RR-TB, variou entre R$ 936 mil no caso base a uma economia de -R$ 1 milhão no cenário alternativo ao final do quinto ano, para MDRTB variou entre uma economia de -R$44 mil no caso base a um custo de R$ 110 mil ao final do quinto ano no cenário alternativo e para XDR-TB variou entre um custo adicional de R$ 188 mil no caso base a um custo adicional de R$ 4 mil ao final do quinto ano no cenário alternativo. RECOMENDAÇÃO PRELIMINAR DA CONITEC: A Conitec, em sua 87ª reunião ordinária, realizada nos dias 03 e 04 de junho de 2020, deliberou que a matéria fosse disponibilizada em consulta pública com recomendação preliminar favorável à incorporação no SUS da bedaquilina para pacientes com tuberculose resistente à rifampicina (RR-TB), a tuberculose multirresistente (MDR-TB) e para tuberculose extensivamente resistente a medicamentos (XDR-TB), condicionada ao monitoramento e apresentação dos dados de vida real, efetividade e segurança, da utilização da bedaquilina pela população brasileira e conforme critérios estabelecidos em protocolo do Ministério da Saúde. CONSULTA PÚBLICA: A Consulta Pública nº 24/2020 foi realizada entre os dias 22/06/2020 a 13/07/2020. Foram recebidas 66 contribuições no total, das quais 19 (29%) foram pelo formulário para contribuições técnico-científicas e 47 (71%) pelo formulário para contribuições sobre experiência ou opinião de pacientes, familiares, amigos ou cuidadores de pacientes, profissionais de saúde ou pessoas interessadas no tema. Das 19 contribuições de cunho técnico-científico, 95% submeteram a contribuição com opinião concordando totalmente com a recomendação preliminar da comissão. Apenas uma contribuição discordou da recomendação preliminar da Conitec, mas foi uma contribuição equivocada e se tratava de outro tema de consulta pública, portanto, foi excluída da análise. Das 47 contribuições recebidas sobre experiência ou opinião, apenas 15 foram analisadas, pois 32 estavam em branco, se tratavam de outro tema ou foram preenchidas inadequadamente. As 15 contribuições remanescentes concordaram 100% com a decisão preliminar da comissão. Após a apreciação das contribuições encaminhadas na consulta pública nº 24/2020, o plenário da Conitec considerou que: I) Foi apresentado um novo preço de USD 340 da bedaquilina pela Johnson & Johnson, sendo proposto um desconto de 15% no preço utilizado no relatório de recomendação preliminar (USD 400); II) Foram enviadas novas estimativas de incidência para pacientes com tuberculose multirresistente, bem como evidência de possíveis limitações na análise de impacto orçamentário; III) A nova análise de impacto orçamentário, utilizando os novos parâmetros enviados na consulta pública, aponta para economia de recursos na população com tuberculose multirresistente e um custo incremental com tuberculose resistente à rifampicina e tuberculose extensivamente resistente no cenário sem taxa de difusão gradual da bedaquilina (100% no primeiro ano de incorporação). No entanto, ao adotarmos o cenário com taxa difusão gradual da bedaquilina, 30% no primeiro ano de incorporação a 70% no quinto ano, os resultados mudam e proporcionam economia de recursos para pacientes com tuberculose resistente à rifampicina e um custo incremental para pacientes com tuberculose multirresistente e tuberculose extensivamente resistente. RECOMENDAÇÃO FINAL DA CONITEC: Os membros da Conitec presentes na 89ª reunião ordinária, no dia 05 de agosto de 2020, deliberaram por unanimidade recomendar a incorporação da bedaquilina para pacientes com tuberculose resistentes à rifampicina, multirresistentes e extensivamente resistente a medicamentos, condicionado a apresentação de dados de vida real e conforme preconizado pelo Ministério da Saúde. Foi assinado o Registro de Deliberação nº 538/2020. DECISÃO: Incorporar a bedaquilina para pacientes com tuberculose resistentes à rifampicina, multirresistentes e extensivamente resistente a medicamentos, condicionado a apresentação de dados de vida real e conforme preconizado pelo Ministério da Saúde, no âmbito do Sistema Único de Saúde - SUS, conforme Portaria nº 36, publicada no Diário Oficial da União nº 168, seção 1, página 77, em 01 de setembro de 2020.

Case Report: Dynamics of Acquired Fluoroquinolone Resistance under Standardized Short-Course Treatment of Multidrug-Resistant Tuberculosis.

We report a case of acquired fluoroquinolone (FQ) resistance under short-course multidrug-resistant tuberculosis (MDR-TB) treatment. The patient was managed at Kabutare hospital, one of the two specialized MDR-TB clinics in Rwanda. A low dose of moxifloxacin was used in the first three critical months. Acquired resistance was identified at the ninth month of treatment, 3 months after stopping kanamycin in a strain initially susceptible only to FQs, kanamycin, and clofazimine. Fluoroquinolone resistance was detected in the same month by deep sequencing as routinely used second-line line probe assay and phenotypic drug susceptibility testing. High-dose FQ, preferably gatifloxacin, should be used to maximize effectiveness.

Clofazimine, a Promising Drug for the Treatment of Babesia microti Infection in Severely Immunocompromised Hosts.

BACKGROUND: Persistent and relapsing babesiosis caused by Babesia microti often occurs in immunocompromised patients, and has been associated with resistance to antimicrobial agents such as atovaquone. Given the rising incidence of babesiosis in the United States, novel drugs are urgently needed. In the current study, we tested whether clofazimine (CFZ), an antibiotic used to treat leprosy and drug-resistant tuberculosis, is effective against B. microti. METHODS: Mice with severe combined immunodeficiency were infected with 107B. microti-infected erythrocytes. Parasites were detected by means of microscopic examination of Giemsa-stained blood smears or nested polymerase chain reaction. CFZ was administered orally. RESULTS: Uninterrupted monotherapy with CFZ curtailed the rise of parasitemia and achieved radical cure. B. microti parasites and B. microti DNA were cleared by days 10 and 50 of therapy, respectively. A 7-day administration of CFZ delayed the rise of parasitemia by 22 days. This rise was caused by B. microti isolates that did not carry mutations in the cytochrome b gene. Accordingly, a 14-day administration of CFZ was sufficient to resolve high-grade parasitemia caused by atovaquone-resistant B. microti parasites. CONCLUSIONS: Clofazimine is effective against B. microti infection in the immunocompromised host. Additional preclinical studies are required to identify the minimal dose and dosage of CFZ for babesiosis.

Drug Effect of Clofazimine on Persisters Explains an Unexpected Increase in Bacterial Load in Patients.

Antituberculosis (anti-TB) drug development is dependent on informative trials to secure the development of new antibiotics and combination regimens. Clofazimine (CLO) and pyrazinamide (PZA) are important components of recommended standard multidrug treatments of TB. Paradoxically, in a phase IIa trial aiming to define the early bactericidal activity (EBA) of CLO and PZA monotherapy over the first 14 days of treatment, no significant drug effect was demonstrated for the two drugs using traditional statistical analysis. Using a model-based analysis, we characterized the statistically significant exposure-response relationships for both drugs that could explain the original findings of an increase in the numbers of CFU with CLO treatment and no effect with PZA. Sensitive analyses are crucial for exploring drug effects in early clinical trials to make the right decisions for advancement to further development. We propose that this quantitative semimechanistic approach provides a rational framework for analyzing phase IIa EBA studies and can accelerate anti-TB drug development.

Synergistic Activity of Clofazimine and Clarithromycin in an Aerosol Mouse Model of Mycobacterium avium Infection.

Infections with nontuberculous mycobacteria (NTM) have a poor prognosis in patients with underlying respiratory diseases. Clofazimine (CFZ) showed both experimental and clinical promising results against clinically relevant NTM. However, there are no data on CFZ in combination with the current recommended treatment; therefore, we aimed to study its in vivo activity in an aerosol mouse model of Mycobacterium avium In an aerosol infection BALB/c mouse model using M. avium strain Chester, we treated 58 mice with four combinations of rifampin (RIF) at 10 mg/kg, CFZ at 25 mg/kg, and clarithromycin (CLR) and ethambutol (EMB) at 100 mg/kg. Treatment efficacy was assessed on the basis of lung CFU counts after 2 (M2) and 4 (M4) months of treatment. At M2, CLR-RIF-EMB was slightly but significantly more efficient than CFZ-RIF-EMB (3.02 ± 0.12 versus 3.55 ± 0.28, respectively, P < 0.01), whereas CLR-CFZ-EMB and CLR-CFZ-RIF-EMB dramatically decreased lung CFU counts by 4.32 and 4.47 log10, respectively, compared to untreated group. At M4, CLR-RIF-EMB was significantly more efficient than CFZ-RIF-EMB (2 ± 0.53 versus 2.66 ± 0.22, respectively, P = 0.01). The addition of CLZ to CLR dramatically decreased the lung CFU count, with CFU counts 5.41 and 5.79 log10 lower in the CLR-CFZ-EMB and CLR-CFZ-RIF-EMB groups, respectively, than in the untreated group. The addition of CFZ to CLR seems to improve the efficacy of CLR as early as M2 and was confirmed at M4. CFZ, in addition to RIF and EMB, on the other hand, is less effective than CLR-RIF-EMB. These results need to be confirmed by similar studies along with CFZ potential for shortening treatment.

Rare case of pacemaker infection with Mycobacterium abscessus.

Though prevalent in the environment, nontuberculous mycobacteria (NTM) have been increasingly identified as pathogenic. Sporadic reports of NTM infection of cardiac implantable electronic devices (CIEDs) have appeared but remain rare. This case describes a CIED infection with Mycobacterium abscessus, the third reported case in the literature. A 63-year-old male presented with a 3-day history of drainage from his pacemaker extraction site. An aspirate grew Mycobacterium abscessus Together with National Jewish Health, a treatment plan was developed, consisting of an induction phase with amikacin, cefoxitin and clarithromycin followed by a maintenance phase with clarithromycin and clofazimine. The clinical course was complicated by cardiac arrhythmia, abscess formation and thoracic osteomyelitis with epidural abscess. This case highlights a rare manifestation of Mycobacterium abscessus disease and suggests the need for further study. Treatment is complicated by unpredictable resistance patterns, complex antimicrobial regimens and the use of arrhythmogenic medications in patients with removed CIEDs.

Acquisition of Cross-Resistance to Bedaquiline and Clofazimine following Treatment for Tuberculosis in Pakistan.

We report on the first six cases of acquired resistance to bedaquiline in Pakistan. Seventy sequential isolates from 30 drug-resistant-tuberculosis patients on bedaquiline-containing regimens were retrospectively tested for bedaquiline resistance by MIC testing and by the detection of mutations in relevant genes. We documented cases failing therapy that developed specific mutations in Rv0678 and had increased MICs associated with cross-resistance to clofazimine during treatment. This study underlines the relevance of surveillance programs following the introduction of new drugs.

Ashy dermatosis: a review.

Ashy dermatosis is characterized by asymptomatic, symmetrically-distributed, gray-colored macules located on the trunk, neck, face, and upper extremities. The condition occurs most commonly in patients with Fitzpatrick phototype III-V skin. The etiology is unknown, but drug ingestion, infection, and genetic factors have been suggested to elicit ashy dermatosis. No gold standard treatments have been established yet. The most successful treatment to date has been clofazimine, although topical tacrolimus, oral dapsone, narrowband ultraviolet light B phototherapy, and isotretinoin have shown treatment success. Ashy dermatosis is primarily a cosmetic concern, but can be a very distressing condition, especially for dark skinned individuals. Therefore, an increase in clinician awareness and more studies are needed to further understand the etiology and treatment options for this disease. This review serves as a single source for clinicians to stay up-to-date regarding the history, clinical presentation, histology, pathogenesis, differential diagnosis, and management options for ashy dermatosis. It also suggests an alternative name that more appropriately encompasses the clinical and histopathologic features, while acknowledging our lack of understanding of its etiology: macular hyperpigmentation of indeterminate etiology.

Synergistic activities of clofazimine with moxifloxacin or capreomycin against Mycobacterium tuberculosis in China.

Clofazimine (CFZ) is a promising candidate drug for use in the management of multidrug-resistant tuberculosis (MDR-TB) patients. In this study, the minimum inhibitory concentration (MIC) method and checkerboard method were used to investigate potential synergies between CFZ and moxifloxacin (MOX) or capreomycin (CAP). Thirty Mycobacterium tuberculosis strains were collected, including 13 MDR strains, 2 extensively drug-resistant (XDR) strains, 3 pan-sensitive strains and 12 strains resistant to other drugs. When the minimum fractional inhibitory concentration indexes (FICIs) were calculated, synergy was found in 21 (70.00%) M. tuberculosis strains against the CFZ/CAP combination and 29 (96.67%) against the CFZ/MOX combination. When the maximum FICIs were calculated, 10 of 15 MDR/XDR strains and 2 of 15 other drug-resistant or pan-sensitive strains showed antagonism against the CFZ/CAP combination, whilst 8 of 15 MDR/XDR strains and 1 of 15 other drug-resistant or pan-sensitive strains showed antagonism against the CFZ/MOX combination, respectively. In conclusion, these findings demonstrate that the combination of CFZ and MOX shows better synergism than the combination of CFZ and CAP. The MDR/XDR isolates are more likely to show antagonism than the other drug-resistant or pan-sensitive strains in both the CFZ/MOX and CFZ/CAP combinations. CFZ in combination with MOX may be a promising drug regimen for the treatment of MDR-TB, particularly for susceptible M. tuberculosis infections.

Shortening Buruli Ulcer Treatment with Combination Therapy Targeting the Respiratory Chain and Exploiting Mycobacterium ulcerans Gene Decay.

Buruli ulcer is treatable with antibiotics. An 8-week course of rifampin (RIF) and either streptomycin (STR) or clarithromycin (CLR) cures over 90% of patients. However, STR requires injections and may be toxic, and CLR shares an adverse drug-drug interaction with RIF and may be poorly tolerated. Studies in a mouse footpad infection model showed that increasing the dose of RIF or using the long-acting rifamycin rifapentine (RPT), in combination with clofazimine (CFZ), a relatively well-tolerated antibiotic, can shorten treatment to 4 weeks. CFZ is reduced by a component of the electron transport chain (ETC) to produce reactive oxygen species toxic to bacteria. Synergistic activity of CFZ with other ETC-targeting drugs, the ATP synthase inhibitor bedaquiline (BDQ) and the bc1:aa3 oxidase inhibitor Q203 (now named telacebec), was recently described against Mycobacterium tuberculosis Recognizing that M. tuberculosis mutants lacking the alternative bd oxidase are hypersusceptible to Q203 and that Mycobacterium ulcerans is a natural bd oxidase-deficient mutant, we tested the in vitro susceptibility of M. ulcerans to Q203 and evaluated the treatment-shortening potential of novel 3- and 4-drug regimens combining RPT, CFZ, Q203, and/or BDQ in a mouse footpad model. The MIC of Q203 was extremely low (0.000075 to 0.00015 µg/ml). Footpad swelling decreased more rapidly in mice treated with Q203-containing regimens than in mice treated with RIF and STR (RIF+STR) and RPT and CFZ (RPT+CFZ). Nearly all footpads were culture negative after only 2 weeks of treatment with regimens containing RPT, CFZ, and Q203. No relapse was detected after only 2 weeks of treatment in mice treated with any of the Q203-containing regimens. In contrast, 15% of mice receiving RIF+STR for 4 weeks relapsed. We conclude that it may be possible to cure patients with Buruli ulcer in 14 days or less using Q203-containing regimens rather than currently recommended 56-day regimens.

Clofazimine inhalation suspension for the aerosol treatment of pulmonary nontuberculous mycobacterial infections.

BACKGROUND: Nontuberculous mycobacteria are recognized as a concern for cystic fibrosis (CF) patients due to increasing disease prevalence and the potential for detrimental effects on pulmonary function and mortality. Current standard of care involves prolonged systemic antibiotics, which often leads to severe side effects and poor treatment outcomes. In this study, we investigated the tolerability and efficacy of a novel inhaled therapeutic in various mouse models of NTM disease. METHODS: We developed clofazimine inhalation suspension (CIS), a novel formulation of clofazimine developed for inhaled administration. To determine the efficacy, minimum inhibitory concentrations were evaluated in vitro, and tolerability of CIS was determined in naïve mouse models over various durations. After establishing tolerability, CIS efficacy was tested in in vivo infection models of both Mycobacterium avium and M. abscessus. Lung and plasma clofazimine levels after chronic treatments were evaluated. RESULTS: Clofazimine inhalation suspension demonstrated antimycobacterial activity in vitro, with MIC values between 0.125 and 2 µg/ml for M. avium complex and M. abscessus. Administration into naïve mice showed that CIS was well tolerated at doses up to 28 mg/kg over 28 consecutive treatments. In vivo, CIS was shown to significantly improve bacterial elimination from the lungs of both acute and chronic NTM-infected mouse models compared to negative controls and oral clofazimine administration. Clofazimine concentrations in lung tissue were approximately four times higher than the concentrations achieved by oral dosing. CONCLUSION: Clofazimine inhalation suspension is a well tolerated and effective novel therapeutic candidate for the treatment of NTM infections in mouse models.

Early efficacy and safety of Bedaquiline and Delamanid given together in a "Salvage Regimen" for treatment of drug-resistant tuberculosis.

BACKGROUND: Drug-Resistant Tuberculosis (DR-TB) patients for whom a WHO recommended regimen along with Bedaquiline (BDQ) cannot be prescribed, Delamanid (DLM) was added along with other drugs to provide a "Salvage Regimen". The experience of the Institute in respect of early efficacy and safety of both drugs given together is presented. OBJECTIVE: To ascertain the early efficacy, safety and tolerability of Bedaquline and Delamanid given together as a part of salvage regimen. METHODS: BDQ and DLM were used together to make regimens along with other drugs where four effective anti TB drugs could not be prescribed as per WHO recommendations. Patients were followed up for sputum smear and culture conversion and adverse events during the treatment. RESULTS: In this cohort study, 53 DR-TB patients (Median age-24) were initiated on regimens containing both BDQ and DLM. Sputum smear conversion was seen in 35% and 94% patients at the end of 1st week and 3rd month respectively. 84% patients had culture conversion at the end of 4th month. 29 adverse events (AE) were reported among 17 patients and there were 11 deaths. QTc prolongation more than 500 MS was seen in only 1 patient. CONCLUSION: BDQ and DLM given together in a salvage regimen is efficacious with low rate of adverse events. The combination provides hope to DR-TB patients with limited treatment options and should be provided as a life saving option.

Initial experience of bedaquiline implementation under the National TB Programme at NITRD, Delhi, India.

BACKGROUND: Bedaquiline (BDQ) was approved for treatment of drug resistant TB (DR-TB) under Conditional Access Programme (CAP) of Revised National Tuberculosis Control Programme (RNTCP) and was also implemented in the National Institute of TB and Respiratory Diseases (NITRD). We present early efficacy and safety of BDQ containing regimens for DR-TB. OBJECTIVE: To ascertain the early efficacy and safety of Bedaquline containing regimens in treatment of DR-TB. METHODS: BDQ containing regimens along with other drugs were designed as per WHO recommendations for DR-TB patients. They were followed up for sputum smear and culture conversion, adverse events during the treatment. RESULTS: A cohort of 290 DR-TB patients (Median age-29.77) were initiated on BDQ containing regimens. Of the available Sputum results, smear conversion was seen in 51% and 91% patients at the end of 1st week and 3rd month respectively. Similarly, 93% and 98% patients had culture conversion at the end of 3rd and 6th month respectively. 201 adverse events (AE) including 47 deaths were reported among 109 patients. QTc prolongation was seen in 29% patients but only 4 required discontinuation of BDQ. Lost to follow up of treatment was about 6%. CONCLUSION: Bedaquiline along with an optimized background regimen has shown early sputum conversion in larger number of difficult to treat patients having additional resistance of second line drugs along with INH and Rifampicin. The regimen is feasible in programmatic conditions and is relatively safe.