Research Spotlight

Posted December 15th 2018

The Sterilizing Effect of Intermittent Tedizolid for Pulmonary Tuberculosis.

Tawanda Gumbo M.D.

Tawanda Gumbo M.D.

Srivastava, S., D. Deshpande, E. Nuermberger, P. S. Lee, K. Cirrincione, K. Dheda and T. Gumbo (2018). “The Sterilizing Effect of Intermittent Tedizolid for Pulmonary Tuberculosis.” Clin Infect Dis 67(suppl_3): S336-s341.

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Background: Linezolid exhibits remarkable sterilizing effect in tuberculosis; however, a large proportion of patients develop serious adverse events. The congener tedizolid could have a better side-effect profile, but its sterilizing effect potential is unknown. Methods: We performed a 42-day tedizolid exposure-effect and dose-fractionation study in the hollow fiber system model of tuberculosis for sterilizing effect, using human-like intrapulmonary pharmacokinetics. Bacterial burden was examined using time to positivity (TTP) and colony-forming units (CFUs). Exposure-effect was examined using the inhibitory sigmoid maximal kill model. The exposure mediating 80% of maximal kill (EC80) was defined as the target exposure, and the lowest dose to achieve EC80 was identified in 10000-patient Monte Carlo experiments. The dose was also examined for probability of attaining concentrations associated with mitochondrial enzyme inhibition. Results: At maximal effect, tedizolid monotherapy totally eliminated 7.1 log10 CFU/mL Mycobacterium tuberculosis over 42 days; however, TTP still demonstrated some growth. Once-weekly tedizolid regimens killed as effectively as daily regimens, with an EC80 free drug 0- to 24-hour area under the concentration-time curve-to-minimum inhibitory concentration (MIC) ratio of 200. An oral tedizolid of 200 mg/day achieved the EC80 in 92% of 10000 patients. The susceptibility breakpoint was an MIC of 0.5 mg/L. The 200 mg/day dose did not achieve concentrations associated with mitochondrial enzyme inhibition. Conclusions: Tedizolid exhibits dramatic sterilizing effect and should be examined for pulmonary tuberculosis. A tedizolid dose of 200 mg/day or 700 mg twice a week is recommended for testing in patients; the intermittent tedizolid dosing schedule could be much safer than daily linezolid.


Posted December 15th 2018

Efficacy Versus Hepatotoxicity of High-dose Rifampin, Pyrazinamide, and Moxifloxacin to Shorten Tuberculosis Therapy Duration: There Is Still Fight in the Old Warriors Yet!

Tawanda Gumbo M.D.

Tawanda Gumbo M.D.

Srivastava, S., D. Deshpande, G. Magombedze and T. Gumbo (2018). “Efficacy Versus Hepatotoxicity of High-dose Rifampin, Pyrazinamide, and Moxifloxacin to Shorten Tuberculosis Therapy Duration: There Is Still Fight in the Old Warriors Yet!” Clin Infect Dis 67(suppl_3): S359-s364.

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Background: One approach that could increase the efficacy and reduce the duration of antituberculosis therapy is pharmacokinetics/pharmacodynamics-based optimization of doses. However, this could increase toxicity. Methods: We mimicked the concentration-time profiles achieved by human equivalent doses of moxifloxacin 800 mg/day, rifampin 1800 mg/day, and pyrazinamide 4000 mg/day (high-dose regimen) vs isoniazid 300 mg/day, rifampin 600 mg/day, and pyrazinamide 2000 mg/day (standard therapy) in bactericidal and sterilizing effect studies in the hollow fiber system model of tuberculosis (HFS-TB). In an intracellular Mycobacterium tuberculosis (Mtb) HFS-TB experiment, we added a 3-dimensional human organotypic liver to determine potential hepatotoxicity of the high-dose regimen, based on lactate dehydrogenase (LDH). Treatment lasted 28 days and Mtb bacterial burden was based on colony counts. We calculated the time to extinction (TTE) of the Mtb population in the HFS-TB and used morphism-based transformation and Latin hypercube sampling to identify the minimum therapy duration in patients. Results: The kill rate of standard therapy in the bactericidal effect and sterilizing effect experiments were 0.97 (95% confidence interval [CI], .91-.99) log10 colony-forming units (CFU)/mL/day, and 0.56 (95% CI, .49-.59) log10 CFU/mL/day, respectively. The high-dose regimen’s bactericidal and sterilizing effect kill rates were 0.99 (95% CI, .96-.99) log10 CFU/mL/day and 0.72 (95% CI, .56-.79) log10 CFU/mL/day, respectively. The upper confidence bound for TTE in patients was 4.5-5 months for standard therapy vs 3.7 months on the high-dose regimen. There were no differences in LDH concentrations between the 2 regimens at any time point (P > .05). Conclusions: The high-dose regimen may moderately shorten therapy without increased hepatotoxicity compared to standard therapy.


Posted December 15th 2018

Prospective Multicenter Assessment of All-Cause Mortality Following Surgery for Adult Cervical Deformity.

Richard Hostin M.D.

Richard Hostin M.D.

Smith, J. S., C. I. Shaffrey, H. J. Kim, P. Passias, T. Protopsaltis, R. Lafage, G. M. Mundis, Jr., E. Klineberg, V. Lafage, F. J. Schwab, J. K. Scheer, E. Miller, M. Kelly, D. K. Hamilton, M. Gupta, V. Deviren, R. Hostin, T. Albert, K. D. Riew, R. Hart, D. Burton, S. Bess and C. P. Ames (2018). “Prospective Multicenter Assessment of All-Cause Mortality Following Surgery for Adult Cervical Deformity.” Neurosurgery 83(6): 1277-1285.

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BACKGROUND: Surgical treatments for adult cervical spinal deformity (ACSD) are often complex and have high complication rates. OBJECTIVE: To assess all-cause mortality following ACSD surgery. METHODS: ACSD patients presenting for surgical treatment were identified from a prospectively collected multicenter database. Clinical and surgical parameters and all-cause mortality were assessed. RESULTS: Of 123 ACSD patients, 120 (98%) had complete baseline data (mean age, 60.6 yr). The mean number of comorbidities per patient was 1.80, and 80% had at least 1 comorbidity. Surgical approaches included anterior only (15.8%), posterior only (50.0%), and combined anterior/posterior (34.2%). The mean number of vertebral levels fused was 8.0 (standard deviation [SD] = 4.5), and 23.3% had a 3-column osteotomy. Death was reported for 11 (9.2%) patients at a mean of 1.1 yr (SD = 0.76 yr; range = 7 d to 2 yr). Mean follow-up for living patients was 1.2 yr (SD = 0.64 yr). Causes of death included myocardial infarction (n = 2), pneumonia/cardiopulmonary failure (n = 2), sepsis (n = 1), obstructive sleep apnea/narcotics (n = 1), subsequently diagnosed amyotrophic lateral sclerosis (n = 1), burn injury related to home supplemental oxygen (n = 1), and unknown (n = 3). Deceased patients did not significantly differ from alive patients based on demographic, clinical, or surgical parameters assessed, except for a higher major complication rate (excluding mortality; 63.6% vs 22.0%, P = .006). CONCLUSION: All-cause mortality at a mean of 1.2 yr following surgery for ACSD was 9.2% in this prospective multicenter series. Causes of death were reflective of the overall high level of comorbidities. These findings may prove useful for treatment decision making and patient counseling in the context of the substantial impact of ACSD.


Posted December 15th 2018

Anti-IL17 therapies for psoriasis.

Alan M. Menter M.D.

Alan M. Menter M.D.

Silfvast-Kaiser, A., S. Y. Paek and A. Menter (2018). “Anti-IL17 therapies for psoriasis.” Expert Opin Biol Ther Nov 30. [Epub ahead of print].

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INTRODUCTION: Interleukin-17 (IL-17) is a proinflammatory cytokine considered to play a significant role in the immunopathogenesis of plaque psoriasis. As a result, focus in clinical trials has undergone a shift towards disease specific targets, with the goals of more effective treatment and reduction in the incidence of serious adverse events. Areas Covered: Two monoclonal antibodies targeting IL-17A (secukinumab, ixekizumab) and one against the IL-17 receptor (brodalumab) are approved for the treatment of moderate-to-severe plaque psoriasis. Herein, the clinical efficacy, safety and tolerability of each is reviewed by summarizing the existing literature (found via PubMed database). Expert Commentary: The development and approval of the IL-17 inhibitor agents secukinumab, ixekizumab, and brodalumab has expanded psoriatic treatment with effective options, validating the importance of the pro-inflammatory role of IL-17 psoriatic pathophysiology. Biologic treatment options for psoriasis will continue to grow, especially IL-17 and IL-23 related agents, with an increasing specificity of agents to be available in the future.


Posted December 15th 2018

Sex as an independent risk factor for long-term survival after endovascular aneurysm repair.

William P. Shutze Sr. M.D.

William P. Shutze Sr. M.D.

Shutze, W. P., Sr., R. Shutze, P. Dhot, M. Forge, A. Salazar and G. O. Ogola (2018). “Sex as an independent risk factor for long-term survival after endovascular aneurysm repair.” J Vasc Surg Nov 26. [Epub ahead of print].

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BACKGROUND: Several vascular surgical procedures, including repair of abdominal aortic aneurysms (AAAs), show poorer outcomes for women than for men. We evaluated the impact of sex-based demographic differences on survival after endovascular aneurysm repair (EVAR). METHODS: We reviewed EVARs performed at our institution between 2003 and 2009 and assessed aortic neck variables (length, diameter, angulation, and calcification), iliac artery variables (length, tortuosity, angulation, and calcification), and AAA diameter. Cox proportional hazards models were used to examine the association between sex and 5-year mortality while adjusting for patients’ demographics, comorbidities, anatomic variables, and AAA parameters. The final model adjusted for sex, age, body mass index, hypertension, iliac artery length, and aortic neck length. RESULTS: Of 336 patients, 278 were male (mean age, 73 years) and 58 were female (mean age, 77 years; P = .0005). Men had more coronary artery bypass grafts (79 vs 8; P = .02) and percutaneous coronary interventions (52 vs 4; P = .03) than women did. Significant differences between the sexes was seen for aortic neck angle, diameter, and length and for iliac artery diameter and length. Men (44%) were more likely than women (22%; P = .0002) to have EVAR performed within the device guidelines. Five-year survival was 73% in men and 49% in women. Multivariable analysis showed that female sex, increase in age, low body mass index (<25 kg/m(2)), and aortic neck length were significantly associated with risk of 5-year mortality. CONCLUSIONS: Women presented at an older age and with a more hostile anatomy. They had reduced survival compared with men after EVAR. After controlling for comorbidities and aortic neck and iliac artery anatomy, sex remained an independent predictor for survival.