Renu Gupta

Randomized Trial of Liposomal Amikacin for Inhalation in Nontuberculous Mycobacterial Lung Disease

Rationale: Lengthy, multidrug, toxic, and low‐efficacy regimens limit management of pulmonary nontuberculous mycobacterial disease. Objectives: In this phase II study, we investigated the efficacy and safety of liposomal amikacin for inhalation (LAI) in treatment‐refractory pulmonary nontuberculous mycobacterial (Mycobacterium avium complex [MAC] or Mycobacterium abscessus) disease. Methods: During the double‐blind phase, patients were randomly assigned to LAI (590 mg) or placebo once daily added to their multidrug regimen for 84 days. Both groups could receive open‐label LAI for 84 additional days. The primary endpoint was change from baseline to Day 84 on a semiquantitative mycobacterial growth scale. Other endpoints included sputum conversion, 6‐minute‐walk distance, and adverse events. Measurements and Main Results: The modified intention‐to‐treat population included 89 (LAI = 44; placebo = 45) patients. The average age of the sample was 59 years; 88% were female; 92% were white; and 80 and 59 patients completed study drug dosing during the double‐blind and open‐label phases, respectively. The primary endpoint was not achieved (P = 0.072); however, a greater proportion of the LAI group demonstrated at least one negative sputum culture (14 [32%] of 44 vs. 4 [9%] of 45; P = 0.006) and improvement in 6‐minute‐walk test (+20.6 m vs. −25.0 m; P = 0.017) at Day 84. A treatment effect was seen predominantly in patients without cystic fibrosis with MAC and was sustained 1 year after LAI. Most adverse events were respiratory, and in some patients it led to drug discontinuation. Conclusions: Although the primary endpoint was not reached, LAI added to a multidrug regimen produced improvements in sputum conversion and 6‐minute‐walk distance versus placebo with limited systemic toxicity in patients with refractory MAC lung disease. Further research in this area is needed. Clinical trial registered with www.clinicaltrials.gov (NCT01315236).

Lack of adherence to evidence-based treatment guidelines for nontuberculous mycobacterial lung disease

RATIONALE The 2007 American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) recommend that patients with pulmonary nontuberculous mycobacterial (PNTM) disease caused by Mycobacterium avium complex (MAC) or M. abscessus be treated with a macrolide-based multidrug antibiotic regimen until sputum culture negative for 1 year. After 6 years, the degree of adherence to recommended guidelines among physicians remains unknown. OBJECTIVE To describe antibiotic treatment practices among physicians treating patients with PNTM in the United States. METHODS A nationally representative sample of 1,286 U.S. physicians was contacted in December 2011 through January 2012; 582 of the responding physicians were treating patients with PNTM and were eligible to participate. Physicians were asked to extract medical record data on the last four patients they treated in the past year with PNTM disease from either MAC or M. abscessus. Treatment patterns were assessed for all patients by NTM species and physician specialty, and compared with the 2007 recommended ATS/IDSA guidelines. MAIN RESULTS Questionnaires were completed by 349 physicians on 915 patients with PNTM, including 744 (81%) with MAC and 174 (19%) with M. abscessus; 3 patients were positive for both. Physicians treated 76 (44%) patients with M. abscessus and 411 (55%) patients with MAC. Only 13% of antibiotic regimens prescribed to patients with MAC met ATS/IDSA guidelines, 56% did not include a macrolide, and 16% were for macrolide monotherapy. Among patients with M. abscessus, 64% of regimens prescribed did not include a macrolide. CONCLUSIONS Adherence to the 2007 ATS/IDSA guidelines for treating PNTM disease is poor. Across all physician specialties evaluated, suboptimal or potentially harmful antibiotic regimens were commonly prescribed.

Pulmonary Deposition and Elimination of Liposomal Amikacin for Inhalation and Effect on Macrophage Function after Administration in Rats

ABSTRACT Pulmonary nontuberculous mycobacterial (PNTM) infections represent a treatment challenge. Liposomal amikacin for inhalation (LAI) is a novel formulation currently in development for the treatment of PNTM infections. The pulmonary deposition and elimination of LAI and its effect on macrophage function were evaluated in a series of preclinical studies in healthy rats. The pulmonary deposition of LAI was evaluated in female rats (n = 76) treated with LAI by nebulizer at 10 mg/kg of body weight per day or 90 mg/kg per day for 27 days, followed by dosing of dually labeled LAI (LAI with a lipid label plus an amikacin label) on day 28 with subsequent lung histological and amikacin analyses. In a separate study for assessment of alveolar macrophage function, rats (n = 180) received daily treatment with LAI at 90 mg/kg per day or 1.5% saline over three 30-day treatment periods followed by 30-day recovery periods; phagocytic and Saccharomyces cerevisiae (yeast) killing capabilities and inflammatory mediator release were assessed at the end of each period. LAI demonstrated equal dose-dependent deposition across all lung lobes and regions. Lipid and amikacin labels showed diffuse extracellular colocalization, followed by macrophage uptake and gradual amikacin elimination. Macrophages demonstrated accumulation of amikacin during treatment periods and nearly complete elimination during recovery periods. No evidence of an inflammatory response was seen. No differences in microsphere uptake or yeast killing were seen between LAI-treated and control macrophages. Neither LAI-treated nor control macrophages demonstrated constitutive inflammatory mediator release; however, both showed normal mediator release on lipopolysaccharide stimulation. LAI is readily taken up by macrophages in healthy rats without compromising macrophage function.