Long-term Safety and Tolerability of Omadacycline for the Treatment of Mycobacterium abscessus Infections.

Background: Mycobacterium abscessus is a virulent human pathogen. Treatment is complex and often poorly tolerated with suboptimal rates of eradication, highlighting the need for improved therapeutics. This study reports clinical experience with omadacycline for treatment of M abscessus infections at five large nontuberculous mycobacterial (NTM) disease clinics across the United States to better understand long-term safety and tolerability. Methods: We conducted a multicenter retrospective chart review of adults with M abscessus infections. All patients treated with omadacycline as part of a multidrug therapeutic regimen through December 2021 were included. Clinical data from time of omadacycline initiation and up to 12 months of follow-up were collected. Descriptive statistics were performed. Results: Analysis included 117 patients. Among patients with M abscessus isolate subspeciation, 58 of 71 (81.7%) were M abscessus spp abscessus. In isolates with reported drug susceptibility testing, 15 of 70 (21.4%) had confirmed susceptibility to macrolides. The most common site of infection was lungs. Median duration omadacycline treatment was 8 months (range, 0.25-33 months; interquartile range, 4-15 months). Omadacycline was discontinued in 60 patients (51.3%); 20 completed planned treatment course, 23 experienced intolerance or adverse event leading to drug cessation, and 17 stopped due to cost, death (unrelated to NTM infection or therapy), or another reason. In those with pulmonary disease, 44 of 95 (46%) had 1 or more negative cultures at time of final microbiological assessment, with 17 of 95 (18%) achieving culture conversion. Conclusions: This study reports data supporting long-term safety and tolerability of omadacycline along with signal of effectiveness in treatment of M abscessus infections.

Population Genomics and Inference of Mycobacterium avium Complex Clusters in Cystic Fibrosis Care Centers, United States.

Mycobacterium avium complex (MAC) species constitute most mycobacteria infections in persons with cystic fibrosis (CF) in the United States, but little is known about their genomic diversity or transmission. During 2016-2020, we performed whole-genome sequencing on 364 MAC isolates from 186 persons with CF from 42 cystic fibrosis care centers (CFCCs) across 23 states. We compared isolate genomes to identify instances of shared strains between persons with CF. Among persons with multiple isolates sequenced, 15/56 (27%) had >1 MAC strain type. Genomic comparisons revealed 18 clusters of highly similar isolates; 8 of these clusters had patients who shared CFCCs, which included 27/186 (15%) persons with CF. We provide genomic evidence of highly similar MAC strains shared among patients at the same CFCCs. Polyclonal infections and high genetic similarity between MAC isolates are consistent with multiple modes of acquisition for persons with CF to acquire MAC infections.

Population Genomics of Mycobacterium abscessus from U.S. Cystic Fibrosis Care Centers.

Rationale:Mycobacterium abscessus is a significant threat to individuals with cystic fibrosis (CF) because of innate drug resistance and potential transmission between patients. Recent studies described global dominant circulating clones of M. abscessus, but detailed genomic surveys have not yet been described for the United States. Objectives: We examined the genetic diversity of respiratory M. abscessus isolates from U.S. patients with CF and evaluated the potential for transmission events within CF Care Centers. Methods: Whole-genome sequencing was performed on 558 M. abscessus isolates from 266 patients with CF attending 48 CF Care Centers in 28 U.S. states as part of a nationwide surveillance program. U.S. isolates were also compared with 64 isolate genomes from 13 previous studies to evaluate the prevalence of recently described dominant circulating clones. Results: More than half of study patients with CF and M. abscessus had isolates within four dominant clones; two clones of M. abscessus subspecies (subsp.) abscessus (MAB) and two clones of M. abscessus subsp. massiliense (MMAS). Acquired drug resistance mutations for aminoglycosides and macrolides were rare in the isolate population, and they were not significantly enriched in dominant clones compared with unclustered isolates. For a subset of 55 patients, there was no relationship between dominant clones and diagnosis of active lung disease (P = 1.0). Twenty-nine clusters of genetically similar MAB isolates and eight clusters of genetically similar MMAS isolates were identified. Overall, 28 of 204 (14%) patients with MAB and 15 of 64 (23%) patients with MMAS had genetically isolates similar to those of at least one other patient at the same CF Care Center. Genetically similar isolates were also found between 60 of 204 (29%) patients with MAB and 19 of 64 (30%) patients with MMAS from different geographic locations. Conclusions: Our study reveals the predominant genotypes of M. abscessus and frequency of shared strains between patients in U.S. CF Care Centers. Integrated epidemiological and environmental studies would help to explain the widespread presence of dominant clones in the United States, including the potential for broad distribution in the environment. Single site studies using systematic, evidence-based approaches will be needed to establish the contributions of health care-associated transmission versus shared environmental exposures.

Long-term follow-up of post-cardiac surgery Mycobacterium chimaera infections: A 5-center case series.

OBJECTIVES: In multiple countries, endovascular/disseminated Mycobacterium chimaera infections have occurred in post-cardiac surgery patients in association with contaminated, widely-distributed cardiac bypass heater-cooler devices. To contribute to long-term characterization of this recently recognized infection, we describe the clinical course of 28 patients with 3-7 years of follow-up for survivors. METHODS: Identified at five hospitals in the United States 2010-2016, post-cardiac surgery patients in the cohort had growth of Mycobacterium avium complex (MAC)/M. chimaera from a sterile site or surgical wound, or a clinically compatible febrile illness with granulomatous inflammation on biopsy. Case follow-up was conducted in May 2019. RESULTS: Of 28 patients, infection appeared to be localized to the sternum in four patients. Among 18 with endovascular/disseminated infection who received combination anti-mycobacterial treatment and had sufficient follow-up, 39% appeared to have controlled infection (>12 months), 56% died, and one patient is alive with relapsed bacteremia. While the number of patients is small and interpretation is limited, four (67%) of six patients who had cardiac prosthesis removal/replacement appeared to have controlled infection compared to three (25%) of 12 with retained cardiac prosthesis (p >0.14; Fisher's exact test). CONCLUSIONS: Given poor response to treatment and potential for delayed relapses, post-cardiac surgery M. chimaera infection warrants aggressive treatment and long-term monitoring.

Efficacy and safety of tigecycline for Mycobacterium abscessus disease.

PURPOSE: Mycobacterium abscessus disease is one of the most difficult mycobacterial infections to cure, as the bacterium is highly resistant to conventional antibiotics. The purpose of this study was to evaluate the efficacy and safety of tigecycline treatment of M. abscessus disease. PROCEDURE: We performed retrospective chart reviews of patients with M. abscessus disease receiving tigecycline-containing regimens at National Jewish Health from January 2009 to December 2017. MAIN FINDINGS: Among the 35 patients, pulmonary disease was the most common presentation of M. abscessus disease (n = 29, 82.9%). Of those receiving tigecycline treatment, 17.4% (4/23) showed microbiological improvement (≥2 consecutive negative sputum cultures), while 86.2% (25/29) and 59.3% (16/27) showed symptomatic and radiological improvements, respectively. The rate of dose reduction or discontinuation of tigecycline owing to adverse drug reactions was 57.1% (20/35) at a median of 56.5 days (IQR 10.8-122.3). The most common adverse drug reactions were gastrointestinal side effects, including nausea, vomiting, and diarrhea. CONCLUSIONS: Tigecycline-containing regimens for M. abscessus disease have a high rate of symptomatic and radiological improvement. However, considering the poor microbiological response and the common adverse effects, selection of patients for tigecycline treatment and monitoring for adverse drug reactions should be performed carefully.

Safety and Effectiveness of Clofazimine for Primary and Refractory Nontuberculous Mycobacterial Infection.

BACKGROUND: Clofazimine is an antimicrobial agent that has activity in vitro against mycobacteria. Increasingly, it has been used for the treatment of nontuberculous mycobacteria (NTM), despite limited data supporting its use in this setting. The objective of this study was to evaluate the safety, tolerability, and clinical outcomes associated with clofazimine in patients with NTM infection. METHODS: This observational-cohort study assessed clofazimine as used for pediatric and adult cystic fibrosis (CF) and non-CF patients with pulmonary and extrapulmonary NTM infection as part of a multidrug regimen from 2006 to 2014. Treatment regimens and adverse drug reactions (ADRs) were captured. RESULTS: A total of 112 patients were included (median age, 62 years); 24 patients (21%) had CF. Eighty-seven (78%) had refractory disease with failure of previous therapy. Fifty-four patients (48%) had Mycobacterium abscessus complex, 41 (37%) had Mycobacterium avium complex, and 16 (14%) had two NTM species. The median duration of clofazimine use was 383 days (range, 3-2,419 days). Sixteen patients (14%) stopped clofazimine due to an ADR after a median of 101 days (95% CI, 63-119). Forty-one of 82 patients (50%) with pulmonary disease converted to negative NTM cultures within 12 months. CONCLUSIONS: Clofazimine was a safe, reasonably tolerated, and active oral drug for NTM infection in our heterogeneous population of pediatric and adult CF and non-CF patients. It should be considered as an alternative drug for treatment of NTM disease.

Improvement in Quality of Life after Therapy for Mycobacterium abscessus Group Lung Infection. A Prospective Cohort Study.

RATIONALE: Mycobacterium abscessus group lung infection is characterized by low cure rates. Improvement in quality of life may be a reasonable treatment goal. OBJECTIVES: The objective of this study was to evaluate change in quality of life in response to therapy, predictors of improvement in quality of life, and association of quality of life with traditional outcome measures. METHODS: Forty-seven patients were treated for Mycobacterium abscessus group lung infection (including one with Mycobacterium chelonae) and were followed prospectively for 2 years between December 2009 and May 2012. St. George's Respiratory Questionnaire (SGRQ) was administered, chest computed tomography (CT) imaging was carried out, and culture data were collected at multiple time points. Predictors of improvement in the SGRQ total score greater than or equal to a minimal clinically important difference (MCID) at 12 months were evaluated. MEASUREMENTS AND MAIN RESULTS: Patients were 85% female and 94% white, with a mean age of 65 years. Nine (20%) had a genetic diagnosis of cystic fibrosis (none F508del homozygous). Coinfection with Mycobacterium avium complex occurred in 28% and Pseudomonas in 26%. Chest CT imaging universally indicated bronchiectasis and nodules; 51% had lung cavities. Treatment included a mean of 17 months of antibiotics, and lung resection in 34%. Seventeen patients with M. avium complex (36%) and one with Mycobacterium kansasii were treated for coinfection. The mean SGRQ total score (SD) at baseline was 35 (20). At all follow-up time points, the mean SGRQ total score (SD) was significantly lower (better) than at baseline: 27 (17) at 3 months, P < 0.01; 27 (19) at 6 months, P < 0.01; 27 (20) at 12 months, P < 0.01; and 30 (22) at 24 months, P = 0.02. At 12 and 24 months, respectively, 60% and 56% had improvement greater than or equal to the MCID in SGRQ total score. Improvement greater than or equal to the MCID at 12 months was positively associated with a history of respiratory exacerbation, isolate susceptible to imipenem-cilastatin, and lung resection surgery, and negatively associated with nodules >4 mm in diameter on chest CT imaging, but these associations were not statistically significant in multivariable analysis. At 24 months, 16 patients (48%) with complete data were culture negative for 1 year and had discontinued M. abscessus group treatment. CONCLUSIONS: Quality of life was a sensitive indicator of treatment response and has the potential to be a useful parameter to guide treatment.

Genome sequencing of Mycobacterium abscessus isolates from patients in the united states and comparisons to globally diverse clinical strains.

Nontuberculous mycobacterial infections caused by Mycobacterium abscessus are responsible for a range of disease manifestations from pulmonary to skin infections and are notoriously difficult to treat, due to innate resistance to many antibiotics. Previous population studies of clinical M. abscessus isolates utilized multilocus sequence typing or pulsed-field gel electrophoresis, but high-resolution examinations of genetic diversity at the whole-genome level have not been well characterized, particularly among clinical isolates derived in the United States. We performed whole-genome sequencing of 11 clinical M. abscessus isolates derived from eight U.S. patients with pulmonary nontuberculous mycobacterial infections, compared them to 30 globally diverse clinical isolates, and investigated intrapatient genomic diversity and evolution. Phylogenomic analyses revealed a cluster of closely related U.S. and Western European M. abscessus subsp. abscessus isolates that are genetically distinct from other European isolates and all Asian isolates. Large-scale variation analyses suggested genome content differences of 0.3 to 8.3%, relative to the reference strain ATCC 19977(T). Longitudinally sampled isolates showed very few single-nucleotide polymorphisms and correlated genomic deletion patterns, suggesting homogeneous infection populations. Our study explores the genomic diversity of clinical M. abscessus strains from multiple continents and provides insight into the genome plasticity of an opportunistic pathogen.

Patients with nontuberculous mycobacterial lung disease exhibit unique body and immune phenotypes.

RATIONALE: Among patients with nontuberculous mycobacterial lung disease is a subset of previously healthy women with a slender body morphotype, often with scoliosis and/or pectus excavatum. We hypothesize that unidentified factors predispose these individuals to pulmonary nontuberculous mycobacterial disease. OBJECTIVES: To compare body morphotype, serum adipokine levels, and whole-blood cytokine responses of patients with pulmonary nontuberculous mycobacteria (pNTM) with contemporary control subjects who are well matched demographically. METHODS: We enrolled 103 patients with pNTM and 101 uninfected control subjects of similar demographics. Body mass index and body fat were quantified. All patients with pNTM and a subset of control subjects were evaluated for scoliosis and pectus excavatum. Serum leptin and adiponectin were measured. Specific cytokines important to host-defense against mycobacteria were measured in whole blood before and after stimulation. MEASUREMENTS AND MAIN RESULTS: Patients with pNTM and control subjects were well matched for age, gender, and race. Patients with pNTM had significantly lower body mass index and body fat and were significantly taller than control subjects. Scoliosis and pectus excavatum were significantly more prevalent in patients with pNTM. The normal relationships between the adipokines and body fat were lost in the patients with pNTM, a novel finding. IFN-γ and IL-10 levels were significantly suppressed in stimulated whole blood of patients with pNTM. CONCLUSIONS: This is the first study to comprehensively compare body morphotype, adipokines, and cytokine responses between patients with NTM lung disease and demographically matched controls. Our findings suggest a novel, predisposing immunophenotype that should be mechanistically defined.

Serodiagnosis of Mycobacterium avium complex pulmonary disease in the USA.

Diagnosis of Mycobacterium avium complex pulmonary disease (MAC-PD) can be difficult. A previous study from Japan reported the usefulness of a serodiagnostic test for MAC-PD. The objective of this study was to evaluate the usefulness of the test in similar patients in the USA. 100 patients with known or suspected MAC-PD and 52 healthy volunteers were enrolled into the study at National Jewish Health, Denver, CO, USA. Serum glycopeptidolipid core immunoglobulin A antibody levels were measured with an enzyme immunoassay (EIA) kit and routine clinical evaluations were performed. The patients were divided into two groups based on clinical evaluation: 87 patients with MAC-PD that met American Thoracic Society criteria, and 13 who did not meet the criteria. The sensitivity and specificity (cut-off point 0.3 U·mL(-1)) of the serodiagnostic test for diagnosing MAC-PD were 70.1% and 93.9%, respectively. Among the 44 patients in the MAC-PD group with two or more positive sputum cultures within the previous 6 months, sensitivity was 81.8%. The EIA kit demonstrated good sensitivity and specificity for the identification of MAC-PD, particularly in patients with two or more positive cultures, and may be useful for rapid MAC-PD diagnosis.

The pharmacokinetics and pharmacodynamics of pulmonary Mycobacterium avium complex disease treatment.

RATIONALE: Currently recommended multidrug treatment regimens for Mycobacterium avium complex (MAC) lung disease yield limited cure rates. This results, in part, from incomplete understanding of the pharmacokinetics and pharmacodynamics of the drugs. OBJECTIVES: To study pharmacokinetics, pharmacodynamics, and drug interactions of multidrug treatment regimens in a large cohort of patients with MAC lung disease. METHODS: We retrospectively collected pharmacokinetic data of all patients treated for MAC lung disease in the Adult Care Unit at National Jewish Health, Denver, Colorado, in the January 2006 to January 2010 period; we retrospectively calculated areas under the time-concentration curve (AUC). Minimum inhibitory concentrations (MIC) of their MAC isolates were retrieved for pharmacodynamic calculations. MEASUREMENTS AND MAIN RESULTS: We included 531 pharmacokinetic analyses, performed for 481 patients (84% females; mean age, 63 yr; mean body mass index, 21.6). Peak serum concentrations (C(max)) below target range were frequent for ethambutol (48% of patients); clarithromycin (56%); and azithromycin (35%). Concurrent administration of rifampicin led to 68%, 23%, and 10% decreases in C(max) of clarithromycin, azithromycin, and moxifloxacin. C(max)/MIC or AUC/MIC ratios associated with bactericidal activity were seldom met; 57% of patients achieved target ratios for ethambutol, versus 42% for clarithromycin, 19% for amikacin, 18% for rifampicin, and 11% for moxifloxacin. CONCLUSIONS: Currently recommended regimens for MAC lung disease yield important pharmacologic interactions and low concentrations of key drugs including macrolides. Pharmacodynamic indices for rifampicin, clarithromycin, amikacin, and moxifloxacin are seldom met. This may partly explain the poor outcomes of currently recommended treatment regimens. Trials of new drugs and new dosing strategies are needed.

Clinical and microbiologic outcomes in patients receiving treatment for Mycobacterium abscessus pulmonary disease.

BACKGROUND: Mycobacterium abscessus can produce a chronic pulmonary infection for which little is known regarding optimal treatment and long-term outcomes. METHODS: We performed a retrospective observational study (2001-2008) including all patients who met American Thoracic Society criteria for M. abscessus pulmonary disease. Our aim was the evaluation of clinical and microbiologic outcomes in patients treated with combined antibiotic and surgical therapy, compared with antibiotic therapy alone. RESULTS: A total of 107 patients were included in the analysis. Patients were predominantly female (83%) and never-smokers (60%), with a mean age of 60 years. Fifty-nine (55%) of 107 patients had coexistent or previous history of Mycobacterium avium complex pulmonary infection. High-resolution chest CT showed bronchiectasis and nodular opacities in 98% of patients and cavities in 44%. Sixty-nine (46 medical, 23 surgical) patients were followed up for a mean duration of 34 months (standard deviation, 21.1 months, range, 2-82 months). Cough, sputum production, and fatigue remained stable, improved, or resolved in 80%, 69%, and 59% of patients, respectively. Twenty (29%) of 69 patients remained culture positive, 16 (23%) converted but experienced relapse, 33 (48%) converted to negative and did not experience relapse, and 17 (16%) died during the study period. There were significantly more surgical patients than medical patients whose culture converted and remained negative for at least 1 year (57% vs 28%; P = .022). CONCLUSIONS: Patients with M. abscessus pulmonary disease who are treated with multidrug antibiotic therapy and surgery or antibiotic therapy alone had similar clinical outcomes. However, surgical resection, in addition to antibiotics, may offer a prolonged microbiologic response.

Targeting mutated K-ras in pancreatic adenocarcinoma using an adjuvant vaccine.

PURPOSE: Codon 12 mutations of K-ras are frequent in pancreatic adenocarcinoma, and represent potential tumor-specific neoantigens. The objective of this study was to assess the safety and efficacy of immunizing patients with resected pancreatic cancer with a vaccine targeted against their tumor-specific K-ras mutation. METHODS: Patients with resected pancreatic cancer, with K-ras mutations at codon 12, were vaccinated once monthly for 3 months with a 21-mer peptide vaccine containing the corresponding K-ras mutation of the patient's tumor. About 200 µg of peptide vaccine was injected intradermally on day 7 of a 10-day course of intradermal granulocyte macrophage colony-stimulating factor. Toxicity was assessed by National Cancer Institute Common Toxicity Criteria v2.0. Immune responses were evaluated by delayed-type hypersensitivity (DTH) tests and the enzyme-linked immunosorbent spot assays. RESULTS: Of 62 screened patients, 24 were vaccinated. There were no grade 3-5 vaccine-specific toxicities. The only National Cancer Institute grade 1 and 2 toxicity was erythema at the injection site (94%). Nine patients (25%) were evaluable for immunologic responses. One patient (11%) had a detectable immune response specific to the patient's K-ras mutation, as assessed by DTH. Three patients (13%) displayed a DTH response that was not specific. Median recurrence free survival time was 8.6 months (95% confidence interval, 2.96-19.2) and median overall survival time was 20.3 months (95% confidence interval, 11.6-45.3). CONCLUSIONS: K-ras vaccination for patients with resectable pancreatic adenocarcinoma proved to be safe and tolerable with however no elicitable immunogenicity and unproven efficacy. Future development of adjuvant vaccine therapies should use more immunogenic vaccines.

Barriers to enrollment of elderly adults in early-phase cancer clinical trials.

Potential strategies to overcome barriers to enrollment of seniors into early-phase trials.

A phase I biological and pharmacologic study of the heparanase inhibitor PI-88 in patients with advanced solid tumors.

PURPOSE: PI-88 is a mixture of highly sulfated oligosaccharides that inhibits heparanase, an extracellular matrix endoglycosidase, and the binding of angiogenic growth factors to heparan sulfate. This agent showed potent inhibition of placental blood vessel angiogenesis as well as growth inhibition in multiple xenograft models, thus forming the basis for this study. EXPERIMENTAL DESIGN: This study evaluated the toxicity and pharmacokinetics of PI-88 (80-315 mg) when administered s.c. daily for 4 consecutive days bimonthly (part 1) or weekly (part 2). RESULTS: Forty-two patients [median age, 53 years (range, 19-78 years); median performance status, 1] with a range of advanced solid tumors received a total of 232 courses. The maximum tolerated dose was 250 mg/d. Dose-limiting toxicity consisted of thrombocytopenia and pulmonary embolism. Other toxicity was generally mild and included prolongation of the activated partial thromboplastin time and injection site echymosis. The pharmacokinetics were linear with dose. Intrapatient variability was low and interpatient variability was moderate. Both AUC and C(max) correlated with the percent increase in activated partial thromboplastin time, showing that this pharmacodynamic end point can be used as a surrogate for drug exposure. No association between PI-88 administration and vascular endothelial growth factor or basic fibroblast growth factor levels was observed. One patient with melanoma had a partial response, which was maintained for >50 months, and 9 patients had stable disease for >or=6 months. CONCLUSION: The recommended dose of PI-88 administered for 4 consecutive days bimonthly or weekly is 250 mg/d. PI-88 was generally well tolerated. Evidence of efficacy in melanoma supports further evaluation of PI-88 in phase II trials.