Treatment outcome of continuation of intravenous amikacin for Mycobacterium abscessus pulmonary disease with a persistent culture positivity after the treatment initiation.

INTRODUCTION: Whether prolonged intravenous amikacin treatment would lead to better treatment results in patients with Mycobacterium abscessus subspecies abscessus (M. abscessus) pulmonary disease (PD) is unknown. We investigated the efficacy of continued amikacin treatment for the microbiological outcome of M. abscessus PD patients with persistent culture positivity after treatment initiation. METHODS: We retrospectively evaluated 62 patients with M. abscessus PD who were treated with intravenous amikacin and beta-lactams along with a macrolide-based regimen at 3 tertiary referral centers in South Korea. The intravenous antibiotic treatment duration was determined by the attending physician. RESULTS: The median treatment durations with amikacin and beta-lactam in the 62 patients were 25.1 and 8.2 weeks, respectively. The overall microbiological cure rate was 29.0%. Among the 62 patients, 44 showed persistent culture positivity at 8 weeks after treatment with an amikacin-containing multidrug regimen. The median parenteral amikacin treatment duration after 8 weeks in these patients was 18.0 weeks. The conditional probability of microbiological cure with continuation of the amikacin-containing regimen in these patients was 18.2% (95% confidence interval 8.2-32.7). Additionally, the conditional probability of microbiological cure in the 34 patients with persistent culture positivity at 12 weeks was 8.8% (95% confidence interval 1.9-23.7). After 16 weeks, the conditional probability of microbiological cure decreased further, reaching 0% at 28 weeks after treatment initiation. CONCLUSION: The continuation of intravenous amikacin therapy was usually not followed by culture conversion in M. abscessus PD patients with persistent sputum culture positivity after treatment initiation.

Interim treatment outcomes in multidrug-resistant tuberculosis using bedaquiline and/or delamanid in South Korea.

PURPOSE: The Korea Centers for Disease Control & Prevention has implemented a review process for the approval of new drugs used to treat patients with multidrug-resistant tuberculosis (MDR-TB) since September 2016. Therefore, this study aimed to evaluate the efficacy and safety of these new drugs bedaquiline (Bdq) and delamanid (Dlm). METHODS: A total of 318 patients with MDR-TB were reviewed by the committee from September 2016 to February 2018; 282 (88.7%) of them were treated with the new drugs (Bdq, 107 patients; Dlm, 108 patients; and both concurrently or sequentially, 67 patients) and retrospectively evaluated. Culture conversion rates, interim treatment outcomes at 12 months, and predictors of unfavorable outcomes were analyzed. Treatment efficacy was also compared between Bdq and Dlm. RESULTS: The mean age of the patients was 49.3 years, and 197 (69.9%) were male. Three patients were HIV seropositive and 151 (53.5%) were quinolone resistant. The culture conversion rates at 2 and 6 months were 57.4% (81/141) and 89.4% (126/141), respectively. A favorable outcome at 12 months was achieved in 84.8% of patients (239/282). Differences in the culture conversion rate or interim treatment outcomes were not statistically significant among the drug susceptibility test patterns or new drugs used. Multivariable analysis showed that age >60 years and body mass index of <18.5 kg/m2 were significant risk factors for unfavorable outcomes at 12 months. CONCLUSIONS: The use of new drugs resulted in satisfactory interim treatment results, without significant differences between them.

Comparison of rivaroxaban and dalteparin for the long-term treatment of venous thromboembolism in patients with gynecologic cancers.

OBJECTIVES: Two randomized, controlled studies comparing outcomes in patients treated with direct oral anticoagulants or low-molecular weight heparin for cancer-associated venous thromboembolism (VTE) have previously been performed. However, gynecologic cancers accounted for approximately 10% of the study populations. We compared the outcomes of patients with primary gynecological cancers who were treated for cancer-associated VTE with either rivaroxaban or dalteparin. METHODS: The 162 eligible patients with gynecologic cancers who were treated with either dalteparin (n=60) or rivaroxaban (n=102) were reviewed. The primary outcome was a composite event, which included recurrence or clinically relevant bleeding events during the therapeutic period. Secondary outcomes were recurrence, clinically relevant bleeding events, and mortality. RESULTS: During the therapeutic period, there were no significant differences between the groups in the proportion of composite events, recurrence, or clinically relevant bleeding. Multivariate analysis using the Cox proportional hazards model also showed no significant difference in the number of composite events and clinically relevant bleeding between the groups. In the rivaroxaban group, 44.0% of patients experienced gastrointestinal bleeding and 24.0% experienced urinary tract bleeding. In the dalteparin group, bleeding was most common in the urinary tract (44.4%) and at the injection site (22.2%). CONCLUSION: In this study, although there were no significant differences in effectiveness or safety between the rivaroxaban and dalteparin groups, rivaroxaban use was associated with a higher rate of clinically relevant bleeding than dalteparin. Therefore, caution should be taken when prescribing rivaroxaban for gynecologic cancer-associated VTE and bleeding events should be carefully monitored.

In Vitro MIC Values of Rifampin and Ethambutol and Treatment Outcome in Mycobacterium avium Complex Lung Disease.

Although it is known that the in vitro MICs of rifampin and ethambutol are poorly correlated with the clinical response in Mycobacterium avium complex (MAC) lung disease (MAC-LD), evidence for this is limited. This study investigated the association between treatment outcome and the in vitro MICs of rifampin and ethambutol in patients with MAC-LD. Among patients diagnosed with macrolide-susceptible MAC-LD between January 2008 and December 2013, 274 patients who were treated with a standard regimen for ≥12 months until August 2017 and whose in vitro MIC results were available were enrolled at a tertiary referral center in South Korea. The MICs of antimicrobial agents were determined using the broth microdilution method. The mean age of the included patients was 60.4 years. The overall treatment success rate was 79.6% (218/274 patients) and tended to decrease with increasing MICs of rifampin and ethambutol, particularly at MICs of ≥8 µg/ml. Treatment success rate was significantly different between MAC isolates with MICs of ≥8 µg/ml for rifampin and ethambutol and those with MICs of <8 µg/ml for rifampin and/or ethambutol (64.9% versus 85.3%, P < 0.001). Multivariate analysis showed that an MIC of ≥8 µg/ml for both drugs and initial sputum acid-fast bacillus (AFB) smear positivity were independent risk factors for an unfavorable response (adjusted odds ratio [OR] = 3.154, 95% confidence interval [CI] = 1.641 to 6.063, and P = 0.001 for an MIC of ≥8 µg/ml; adjusted OR = 2.769, 95% CI = 1.420 to 5.399, and P = 0.003 for initial sputum AFB smear positivity). These findings suggest that the in vitro MICs of rifampin and ethambutol may be related to treatment outcome in MAC-LD.

Treatment outcomes of refractory MAC pulmonary disease treated with drugs with unclear efficacy.

We aimed to investigate the treatment outcomes of patients with refractory Mycobacterium avium complex (MAC) lung disease treated with regimens containing drugs with unclear efficacy. Of all patients diagnosed with MAC lung disease between April 2004 and September 2012 at a tertiary referral center in South Korea, the outcomes of 51 patients treated with regimens containing drugs with unclear efficacy (clofazimine, moxifloxacin, rifabutin, and linezolid) because of treatment failure after receiving standard treatment were retrospectively analyzed. The mean age (standard deviation) of the 51 patients was 59.0 (10.3) years and 29 (56.9%) were male. The etiologic agent was M. avium in 17 patients (33.3%) and Mycobacterium intracellulare in 34 patients (66.7%); 42 patients (82.4%) had the fibrocavitary form of the disease. Of the 51 patients, 26, 28, 35, and 7 received clofazimine-, moxifloxacin-, rifabutin-, and linezolid-containing regimens (numbers are not mutually exclusive), with median drug administration durations of 147, 128, 209, and 88 days, respectively. Overall, 8 patients (15.7%) had a favorable response. Treatment outcomes did not differ by drug regimen or even by the combination of more than 2 drugs. The treatment outcomes of patients with refractory MAC lung disease were unsatisfactory with regimens containing possibly effective drugs such as clofazimine, moxifloxacin, rifabutin and linezolid.

The efficacy of rifabutin for rifabutin-susceptible, multidrug-resistant tuberculosis.

OBJECTIVE: We investigated the efficacy of rifabutin (RFB)-containing regimens for the treatment of RFB-susceptible, multidrug-resistant tuberculosis (MDR-TB). METHODS: From 146 patients diagnosed with MDR-TB between January 2006 and December 2009 at Asan Medical Center in South Korea, 31 patients (21.2%) were found to have RFB-susceptible MDR-TB. Of these 31 patients, 14 patients who had been treated with RFB for more than one month were included. Forty-two patients with RFB-resistant MDR-TB were selected as a control group, and the outcomes of both groups were retrospectively compared. RESULTS: Of 14 patients with RFB-susceptible MDR-TB, the mean age was 44.4 years and the proportion of extensively drug-resistant TB (XDR-TB) was 35.7% (5/14). Baseline characteristics and the drug resistance pattern (except RFB) did not differ between the two groups. Treatment success was achieved in 12 (85.7%) patients in the RFB group: cure in 10 (71.4%) and treatment completion in two (14.3%). The treatment success rate was 52.4% (22/42) in the control group (p = 0.032). Treatment failure was more common in patients of the control group (40.5% vs. 14.3%; p = 0.106). CONCLUSIONS: RFB is useful as an additional drug in the treatment of MDR-TB in patients with RFB-susceptible MDR-TB.