Abstract Rationale Amikacin liposome inhalation suspension (ALIS), as part of a combination antibacterial regimen, is currently the only FDA-approved treatment for patients with refractory Mycobacterium avium complex lung disease (rMACLD). MAC is the most common cause of nontuberculous mycobacterial lung disease (NTMLD). A real-world evidence study demonstrated significant decreases in hospitalizations from baseline over a 12-month follow-up period following ALIS initiation; however, study conclusions were limited by the absence of a comparator arm. In this study, we compared healthcare resource utilization in US patients who initiated ALIS versus non-ALIS antibiotic treatment for possible rMACLD. Methods This was a retrospective claims analysis using the Merative™ MarketScan® databases between 2016 and 2021. As no diagnosis codes for MACLD exist in claims, we defined 2 cohorts of patients receiving treatment for possible rMACLD as follows: 1) patients who initiated ≥28 days of continuous treatment with ALIS; and 2) patients who initiated ≥28 days of continuous treatment with ≥1 non-ALIS antibiotic used to treat rMACLD (i.e., parenteral aminoglycoside, clofazimine, fluoroquinolones, linezolid, tedizolid, or bedaquiline) ≥6 months after initiating treatment used for MACLD (i.e., with a combination of ≥2 antibiotics from a macrolide, ethambutol, and a rifamycin). The date of initiating treatment with ALIS or non-ALIS antibiotic for rMACLD was referred to as the index date. Other inclusion criteria: ≥1 diagnosis code for NTMLD anytime pre-index, ≥6 months continuous eligibility pre-index, and ≥12 months continuous eligibility post-index. Hospitalizations (all-cause, respiratory-related, NTMLD-related) and emergency room (ER) visits at 0-6 and 7-12 month post-index periods were compared with baseline (6 month pre-index period) per treatment arm. Results A total of 116 patients comprised the ALIS cohort and 63 patients the non-ALIS cohort. In the ALIS cohort, statistically significant reductions from baseline in all-cause, respiratory-related, and NTMLD-related hospitalizations were observed during the 7-12 month post-index period (Table). In contrast, the non-ALIS cohort did not show significant reductions from baseline in hospitalizations at follow-up. No statistically significant changes from baseline in ER visits were observed in either group. Conclusions Patients treated with ALIS for rMACLD had statistically significant reductions in hospitalizations from baseline during the 7-12 month post-index period, whereas no statistically significant improvements in hospitalizations were observed in the non-ALIS antibiotics group.
B-273 Clinical Validation of a Novel Lateral Flow Assay for Rapid and Sensitive Urine Fentanyl Screening
Abstract Background The urgent need for rapid fentanyl detection at the point-of-care originates from its involvement in a high number of overdose deaths, primarily due to illicit use. Given fentanyl's potency compared to traditional opioids, accurate and sensitive detection is critical. Current lateral flow assays (LFA) cannot detect single-digit concentrations and may yield false negatives due to their lower sensitivity. Herein, we evaluate the clinical performance of a novel LFA (InstaStrip Fentanyl Rapid Test (urine)) with 1 ng/mL cutoff for fentanyl and no cross-reactivity for norfentanyl, offering enhanced sensitivity for effective overdose prevention at the ED. Methods A total of 172 urine samples submitted for UDS analysis were used for comparison studies. Fentanyl concentrations were categorized in 5 groups to cover various concentration categories around the cutoff of the LFA (1 ng/mL). These categories are: drug-free (<0.1 ng/mL, n=68), 0.1-0.5 ng/mL (n=14), 0.5-0.9 ng/mL (n=15), 1-1.5 ng/mL (n=9) and > 1.5 ng/mL (n= 66). Concentrations were determined by in-house LC-MS/MS methods validated according to CLIA standards, with fentanyl concentrations quantitated in the ABSciex software. For LFA testing, 150 μL of urine was added to a reagent tube containing dried rabbit anti-fentanyl antibody conjugated gold nanoparticles. After 20 sec of brief shaking, a test strip was inserted into the test tube. After 5 min, qualitative results were read as follow: both the control and test lines were visible in negative results, whereas only the control lines were visible in positive results. Method comparison study of the LFA was conducted by three operators who were blinded to the LC-MS/MS results. Result comparisons were made between the LFA strip and LC-MS/MS results, as well as among different operators for the same samples. Results Of the 75 urine samples with LC-MS/MS fentanyl concentrations ≥ 1 ng/mL, 74 produced consistently positive results using the InstaStrip Fentanyl Rapid Test. Of the 97 urine samples with LC-MS/MS fentanyl concentrations < 1 ng/mL, 96 produced consistently negative results using the InstaStrip Fentanyl Rapid Test. Using the LC-MS/MS as the gold standard method and 1 ng/mL as a cutoff, the clinical sensitivity of InstaStrip Fentanyl Rapid Test was calculated to be 98.67% (95% confidence interval (CI) 92.79-99.97%), and the clinical specificity was 98.97% (95% CI 94.39-99.97%). Consistent results among three operators were obtained for 100% of the “drug free”, “0.1- 0.5 ng/mL” and > 1.5 ng/mL groups, whereas 93.3 % (14 out of 15) and 88.9% (7 out of 8) were obtained for the “0.5-0.9 ng/mL” and “1-1.5 ng/mL” groups, respectively. The two samples with a singlet discrepant result (1 false positive and 1 false negative) in the triplicate experiments contained fentanyl concentrations of 0.9 and 1.0 ng/mL respectively, which are very close to the cutoff value. Conclusions In this study, the InstaStrip Fentanyl Rapid Test (urine) demonstrated high clinical sensitivity (98.67%), high specificity (98.97%) and high reproducibility showing that it may be useful in screening and identifying patients with fentanyl overdose in minutes in an emergency setting. This would facilitate appropriate patient triaging for optimal clinical care.
1865. Refractory Nontuberculous Mycobacterial Pulmonary Disease: Natural History and Burden of Illness in Patients from the US Bronchiectasis and NTM Research Registry (BRR)
Abstract Background Nontuberculous mycobacterial pulmonary disease (NTMPD) is a chronic lung infection that is challenging to treat, especially refractory NTMPD. Data are limited on the natural history, risk profile, and burden of refractory NTMPD. The objective of this study was to evaluate the burden of illness (BOI) among patients with NTMPD who later develop refractory NTMPD vs those who do not. Methods This was a retrospective analysis using BRR data. Patients treated for NTMPD were included and stratified as refractory (received oral clofazimine/bedaquiline or inhaled amikacin/ALIS, or remained sputum culture positive despite ≥ 6 months of treatment) or nonrefractory. Modified bronchiectasis severity index (mBSI) at baseline visit and BOI including comorbid conditions and surgeries at the treatment visit were compared by cross-sectional analysis between the two groups. Longitudinal analysis of BOI focused on exacerbations and hospitalizations in the refractory group at their pre-refractory visit and refractory visit (first visit meeting the refractory definition). Results A total of 1,064 patients treated for NTMPD were included: 462 (43.4%) refractory and 602 (56.6%) nonrefractory. During the baseline period, the refractory group had more severe bronchiectasis (Table 1, mBSI, mean [SD], 7.3 [3.4] vs 6.7 [3.4]). At the time of treatment, bronchiectasis was more common in the refractory than nonrefractory (96.2% vs 89.7%) group, as were hemoptysis (26.6% vs 16.3%) and GERD (50.5% vs 39.9%). Except BMI, there were no statistically significant differences between the pre-refractory and nonrefractory treatment visits (Table 2). In the refractory group, exacerbations and hospitalizations remained high from the pre-refractory to refractory visit (45.6% vs 39.4% and 13.3% vs 12.8%, respectively). Oxygen and bronchial hygiene use increased from the pre-refractory to the refractory visit (5.2% vs 9.3% and 54.5% vs 61.7%, respectively) consistent with increased management of respiratory conditions when not responding to treatment (Table 2). Conclusion Refractory NTMPD imposes a high disease burden on patients in the BRR. This high burden was present at pre-refractory visits and through the development of refractory status. Disclosures Timothy R. Aksamit, MD, AstraZeneca: Advisor/Consultant|Baxter International, Hill-Rom: Advisor/Consultant|Insmed Incorporated: Advisor/Consultant|Johnson & Johnson: Advisor/Consultant|Redhill Biopharma: Advisor/Consultant|RespirTech: Advisor/Consultant|Spero Therapeutics: Advisor/Consultant|Zambon: Advisor/Consultant David M. Mannino, MD, AstraZeneca: Advisor/Consultant|GlaxoSmithKline: Advisor/Consultant|Up to Date: Advisor/Consultant Ping Wang, PhD, Insmed Incorporated: Salary|Insmed Incorporated: Stocks/Bonds Mariam Hassan, PhD, B. Pharm, Insmed Incorporated: Salary|Insmed Incorporated: Stocks/Bonds
Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)
1
Vascular endothelial growth factor-A (VEGF) is critical for angiogenesis but fails to induce neovascularization in ischemic tissue lesions in mice lacking endothelial nitric oxide synthase (eNOS). VEGF receptor-2 (VEGFR-2) is critical for angiogenesis, although little is known about the precise role of endothelial VEGFR-1 and its downstream effectors in this process. Here we have used a chimeric receptor approach in which the extracellular domain of the epidermal growth factor receptor was substituted for that of VEGFR-1 (EGLT) or VEGFR-2 (EGDR) and transduced into primary cultures of human umbilical vein endothelial cells (HUVECs) using a retroviral system. Activation of HUVECs expressing EGLT or EGDR induced rapid phosphorylation of eNOS at Ser1177, release of NO, and formation of capillary networks, similar to VEGF. Activation of eNOS by VEGFR-1 was dependent on Tyr794 and was mediated via phosphatidylinositol 3-kinase, whereas VEGFR-2 Tyr951 was involved in eNOS activation via phospholipase Cγ1. Consistent with these findings, the VEGFR-1–specific ligand placenta growth factor-1 activated phosphatidylinositol 3-kinase and VEGF-E, which is selective for VEGFR-2–activated phospholipase Cγ1. Both VEGFR-1 and VEGFR-2 signal pathways converged on Akt, as dominant-negative Akt inhibited the NO release and in vitro tube formation induced following activation of EGLT and EGDR. The identification Tyr794 of VEGFR-1 as a key residue in this process provides direct evidence of endothelial VEGFR-1 in NO-driven in vitro angiogenesis. These studies provide new sites of modulation in VEGF-mediated vascular morphogenesis and highlight new therapeutic targets for management of vascular diseases.