A prospective patient registry to monitor safety, effectiveness, and utilisation of bedaquiline in patients with multidrug-resistant tuberculosis in South Korea.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) represents a major public health concern, with an ongoing need for new effective treatments. Bedaquiline is an oral diarylquinoline that has shown encouraging treatment success and culture conversion rates in MDR-TB. METHODS: A South Korean patient registry was set up across 19 centres between 2016 and 2018 for the prospective collection of data from patients with MDR-TB who received either a bedaquiline-containing or a non-bedaquiline-containing regimen. Treatment was at the physician's discretion (bedaquiline use requiring approval by special committee) and was based on patient characteristics, disease status, and local treatment guidelines. RESULTS: The safety population included 172 patients (88 bedaquiline and 84 non-bedaquiline). The mean (standard deviation, SD) duration of follow-up was 24.3 (9.5) months. Mean (SD) durations of treatment were 5.4 (1.8) months in bedaquiline-treated patients and 15.7 (6.7) months in the non-bedaquiline group. Treatment success (cured and treatment completed according to WHO 2013 treatment outcome definitions) was achieved by 56.3% of bedaquiline-treated and 45.2% of non-bedaquiline-treated patients. Sputum culture conversion rates were 90.4% and 83.7% with and without bedaquiline, respectively. Diarrhoea and nausea were the most frequently reported treatment-emergent adverse events (TEAEs) in the bedaquiline group (27.3% [24/88] and 22.7% [20/88], respectively). The most frequent bedaquiline-related TEAEs were prolonged QT interval (10.2%; 9/88), and diarrhoea and nausea (9.1% each; 8/88). QT interval prolongation was reported in 19.3% (17/88) of bedaquiline-treated and 2.4% (2/84) of non-bedaquiline-treated patients, but bedaquiline was not discontinued for any patient for this reason. There were 13 (14.7%) and three (3.6%) deaths in the bedaquiline-treated and non-bedaquiline groups, respectively. Review of fatal cases revealed no unexpected safety findings, and no deaths were bedaquiline-related. The most common cause of death was worsening cancer (three patients). Patients in the bedaquiline group tended to have poorer baseline risk profiles than non-bedaquiline patients and were more likely to have relapsed or already failed second-line treatment. Interpretation of mortality data was complicated by high rates of loss to follow-up in both groups. CONCLUSIONS: The South Korean registry findings support previous risk/benefit observations and the continued use of bedaquiline as part of combination therapy in patients with MDR-TB.

Bedaquiline safety, efficacy, utilization and emergence of resistance following treatment of multidrug-resistant tuberculosis patients in South Africa: a retrospective cohort analysis.

BACKGROUND: This retrospective cohort study assessed benefits and risks of bedaquiline treatment in multidrug-resistant-tuberculosis (MDR-TB) combination therapy by evaluating safety, effectiveness, drug utilization and emergence of resistance to bedaquiline. METHODS: Data were extracted from a register of South African drug-resistant-tuberculosis (DR-TB) patients (Electronic DR-TB Register [EDRWeb]) for newly diagnosed patients with MDR-TB (including pre-extensively drug-resistant [XDR]-TB and XDR-TB and excluding rifampicin-mono-resistant [RR]-TB, as these patients are by definition not multidrug-resistant), receiving either a bedaquiline-containing or non-bedaquiline-containing regimen, at 14 sites in South Africa. Total duration of treatment and follow-up was up to 30 months, including 6 months' bedaquiline treatment. WHO treatment outcomes within 6 months after end-of-treatment were assessed in both patient groups. Longer term mortality (up to 30 months from treatment start) was evaluated through matching to the South African National Vital Statistics Register. Multivariable Cox proportional hazards analyses were used to predict association between receiving a bedaquiline-containing regimen and treatment outcome. RESULTS: Data were extracted from EDRWeb for 5981 MDR-TB patients (N = 3747 bedaquiline-treated; N = 2234 non-bedaquiline-treated) who initiated treatment between 2015 and 2017, of whom 40.7% versus 80.6% had MDR-TB. More bedaquiline-treated than non-bedaquiline-treated patients had pre-XDR-TB (27.7% versus 9.5%) and XDR-TB (31.5% versus 9.9%) per pre-2021 WHO definitions. Most patients with treatment duration data (94.3%) received bedaquiline for 6 months. Treatment success (per pre-2021 WHO definitions) was achieved in 66.9% of bedaquiline-treated and 49.4% of non-bedaquiline-treated patients. Death was reported in fewer bedaquiline-treated (15.4%) than non-bedaquiline-treated (25.6%) patients. Bedaquiline-treated patients had increased likelihood of treatment success and decreased risk of mortality versus non-bedaquiline-treated patients. In patients with evaluable drug susceptibility testing data, 3.5% of bedaquiline-susceptible isolates at baseline acquired phenotypic resistance. Few patients reported bedaquiline-related treatment-emergent adverse events (TEAEs) (1.8%), TEAE-related bedaquiline discontinuations (1.4%) and QTcF values > 500 ms (2.5%) during treatment. CONCLUSION: Data from this large cohort of South African patients with MDR-TB showed treatment with bedaquiline-containing regimens was associated with survival and effectiveness benefit compared with non-bedaquiline-containing regimens. No new safety signals were detected. These data are consistent with the positive risk-benefit profile of bedaquiline and warrant continued implementation in combination therapy for MDR-TB treatment.

Determination of relative response factors of impurities in paclitaxel with high performance liquid chromatography equipped with ultraviolet and charged aerosol detectors.

A case study was conducted to determine the relative response factors (RRFs) of paclitaxel-related impurities by high performance liquid chromatography (HPLC) equipped with an ultraviolet (UV) detector and charged aerosol detector (CAD) in tandem. The peak response using CAD was independent of analyte structure in an isocratic analysis for this application. After a sample containing known and unknown impurities was analyzed with HPLC-UV-CAD, an empirical approach was developed to calculate the RRFs for all impurities. The RRFs of known impurities were also determined by linear calibration curves. For known impurities, the RRFs values determined with two approaches are comparable. The new approach is effective yet simpler to determine the RRFs for unknown impurities or degradation products since the need for obtaining authentic pure materials was eliminated.

Investigation of mass-balance issue in e-beam sterilized paclitaxel eluting coronary stents by SPME/GC-MS.

Paclitaxel eluting coronary stents were sterilized by e-beam in a closed system, to investigate sterilization related mass-balance issues and evaluate potential volatile paclitaxel degradation products. A solid-phase microextraction (SPME) method utilizing a polydimethyl-siloxane/divinyl-benzene (PDMS/DVB) fiber was optimized for extracting the volatiles from the head-space of the sterilized stents. GC-MS was used for separation, identification, and quantitation of the components. Benzaldehyde and benzoic acid were identified as paclitaxel related volatile degradation products. Three groups of stents were included in the study, a control group (not exposed to e-beam), a group sterilized at 25 kGy, and a final group sterilized at 75 kGy. The stents sterilized by e-beam at 75 kGy contained significantly higher levels of benzoic acid relative to the controls and the stents at 25 kGy contained intermediate levels of benzoic acid. The benzaldehyde levels increased in the 25 kGy e-beam sterilized stents relative to the control but remained fairly constant in the 75 kGy e-beam sterilized stents relative to the 25 kGy e-beam results. Mechanism for the formation of benzoic acid and benzaldehyde from paclitaxel was proposed. The levels of benzoic acid and benzaldehyde observed on the stents did not resolve the original mass-balance issue, but most likely contribute to the lack of mass balance observed for paclitaxel.

Mass balance in rapamycin autoxidation.

The immunosuppressant drug rapamycin is a complex polyene-containing natural product which undergoes autoxidation. The resulting product mixtures contained numerous monomeric and oligomeric compounds, which represented challenges for addressing mass balance in forced degradation studies and in analysis of aged developmental drug-eluting stents. A combination of SEC with ultraviolet and refractive index detection and RP-HPLC was used to account for drug loss and product formation. The mass balance methodology was subsequently validated for the determination of rapamycin and composite rapamycin autoxidation product material in developmental stent samples. This mass balance approach may find general applicability in other situations where drugs degrade to a plethora of products, which cannot be determined individually and summed.

Evaluation of charged aerosol detector for purity assessment of protein.

Commercially available protein reference standard materials are widely used for the quantitation of intact proteins in biopharmaceuticals, food, and consumer products. However, the purity of protein reference standard materials are often assumed to be 100% or they may be assigned an inaccurate value because the methods used to determine protein purity often lack specificity and accuracy. In this study, a high performance liquid chromatography system equipped with a charged aerosol detector (HPLC-CAD) was used for universal response detection to provide a practical, specific, accurate, and robust method for the determination of the purity of protein reference standard materials. This work demonstrates the near uniform CAD responses for six proteins with different molecular weights and different structures. Flow injection analysis (FIA) was used to compare protein responses under various mobile phase and diluent compositions. Similar CAD responses for all six proteins were observed when the mobile phase composition included trifluoroacetic acid (TFA) and acetonitrile. These are typical conditions regularly applied to the separation of proteins by reversed phase (RP) chromatography. The universal response feature of the CAD was employed to determine the purity of Bowman-Birk inhibitor (BBI) reference standard material. This protein is an important ingredient in soybean products and has various therapy applications. Three major components were observed in the commercially available reference standard material by reversed phase gradient HPLC, BBI-Native, BBI-Isoform 1, and BBI-Isoform 2 at relative compositions of 60.0%, 34.2%, and 5.8%, respectively.

Stir bar sorptive extraction combined with GC-MS/MS for determination of low level leachable components from implantable medical devices.

Identification and determination of leachable components are essential for the safety assessment of implantable medical devices. The safety concern threshold (SCT) for leachable components is 0.15 µg/day for genotoxic or carcinogenic compounds and 1.5 µg/day for others. Regulatory agencies require extraction of a whole medical device using an extraction media that simulates in vitro conditions. Large-sized medical devices therefore require large volumes of aqueous media, leading to extracts of very low concentrations of the targeted analytes. Analysis of these dilute solutions is often challenging, and pre-concentration steps are time consuming and can cause significant sample loss. Stir bar sorptive extraction (SBSE) has proven to be a very useful sample preparation technique that is simple and uses no (or minimal (<1 ml)) aqueous or organic solvents. When combined with a highly selective and sensitive GC-MS/MS analysis, volatile and semi-volatile leachable components can be determined at levels below the SCT of 150 ng/device. An SBSE-GC-MS/MS method using multiple reaction monitoring detection was validated for determination of antioxidant related leachable breakdown products from orthopedic knee-inserts made from ultra high molecular weight polyethylene.

Method development and validation for the determination of 2,4,6-tribromoanisole, 2,4,6-tribromophenol, 2,4,6-trichloroanisole, and 2,4,6-trichlorophenol in various drug products using stir bar sorptive extraction and gas chromatography-tandem mass spectrometry detection.

Recently, haloanisoles and halophenols are associated with multiple product recall situations in the pharmaceutical industry. The majority of the recalls are associated with consumer complaints due to the presence of 2,4,6-tribromoanisole, as extremely low levels of this component can be easily detected by the human nose. As part of the root cause analysis to address the cause of the consumer complaints, a GC-MS/MS based analytical method combined with stir bar sorptive extraction (SBSE) sample preparation was developed for determination of halophenols and haloanisoles from various drug product formulations. The method also applies to the analysis of 2,4,6-tribromoanisole analysis in various packaging materials. The optimized MS/MS method is based on component-specific MRM transitions. The detection limit is component dependent and in the range of 1-100 pg/tablet for solid dosage formulations and 0.04-4 ng/L for water based solutions. Deuterated tribromoanisole was used as internal standard for quantitation. The paper also may provide guidance for performing trace level method validation in the regulated Pharmaceutical Industry.

Molecular imaging of drug-eluting coronary stents: method development, optimization and selected applications.

A molecular imaging application was developed to characterize the drug distribution on CYPHER® and NEVO™ Drug-eluting Stents using MALDI Qq-ToF analytical methodology. The coating matrix, laser energy, laser frequency, spatial resolution (related to rastering speed) and mass spectrometer parameters were optimized to analyze drug distribution in both durable and biodegradable polymer matrices. The developed method was extended to generate data from stents explanted from porcine coronary arteries. Due to the method's intrinsic specificity, it offers a significant advantage over other techniques in that it allows low-level detection of the target molecule without biological interferences from the blood or tissue. The method is also capable of detecting drug-related degradation products both from the finished stent product and from explanted stents.

Forced degradation studies of rapamycin: identification of autoxidation products.

The immunosuppressant drug rapamycin, also known as Sirolimus, underwent autoxidation under mild conditions to give numerous monomeric and oligomeric compounds, which were generally characterized by size-exclusion chromatography and NP-HPLC with UV and MS detection. Some of the more predominant products, epoxides and ketones, were isolated and identified. Two epoxides and 10S-epimer of rapamycin were described for the first time. Observed rapamycin isomers were also addressed. Computational chemistry was used to provide mechanistic insights. Formation of the majority of the rapamycin products could be rationalized with free radical-mediated autoxidation reactions involving alkene and alcohol sites. Methodological aspects of oxidative stress testing are discussed.

Effects of E-BEAM sterilization on drug-eluting stents: paclitaxel degradation elucidated by LC-MS-MS with information-dependent acquisition.

Effects of sterilization by electron beam (E-BEAM) on paclitaxel (1) mixed with poly(DL-lactide-co-glycolide) (PLG) in reservoirs of COSTAR Stents are examined by using liquid chromatography-mass spectrometry (LC-MS-MS) techniques with information-dependent acquisition (IDA). Numerous degradation products of 1 are formed in a ß-radiation dose-dependent manner to give plethora of low-level degradants. This behavior, together with multiple interferences from PLG-related compounds, creates considerable challenges for analysis of the drug/PLG mixtures. IDA methods with different survey scans are proven to be very efficient in elucidating degradation pathways and in identifying numerous products. Combined LC-MS-MS results from analysis of sterilized drug substance and stents indicate that water addition and oxidative processes together with the isomerization are largely responsible for degradation of 1 under E-BEAM sterilization conditions used.