Jan-Willem C Alffenaar

Prof. Dr. Jan-Willem C Alffenaar

Faculty of Medicine and Health, School of Pharmacy, University of Sydney, Sydney, NSW 2000, Australia
orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
8 November 2017 in Clinical Infectious Diseases
Verified
Journal Article
Closed access
PDF file
TNThi Van Anh Nguyen
Thi Van Anh Nguyen
RARichard Anthony
Richard Anthony
ABAnne-Laure Banuls
Anne-Laure Banuls
HVHoa Vu
Hoa Vu
JAJan-Willem C Alffenaar
Jan-Willem C Alffenaar
Bedaquiline, a new anti-tuberculosis drug, has already been used in more than 50 countries. The emergence of bedaquiline resistance is alarming, as it may result in the rapid loss of this new drug. This paper aims to review currently identified mechanisms of resistance, the emergence of bedaquiline resistance, and discuss strategies to delay the resistance acquisition. In vitro and clinical studies as well as reports from the compassionate use have identified the threat of bedaquiline resistance and cross-resistance with clofazimine, emphasizing the crucial need for the systematic surveillance of resistance. Currently known mechanisms of resistance include mutations within the atpE, Rv0678 and pepQ genes. The development of standardized drug susceptibility testing (DST) for bedaquiline is urgently needed. Understanding any target and non-target based mechanisms is essential to minimize the resistance development and treatment failure, help to develop appropriate DST for bedaquiline and genetic based resistance screening.

1 March 2020 in International Journal of Infectious Diseases
Verified
Journal Article
Open access
GMGiovanni Battista Migliori
Giovanni Battista Migliori
STSimon Tiberi
Simon Tiberi
AZAlimuddin Zumla
Alimuddin Zumla
EPEskild Petersen
Eskild Petersen
Chakaya Muhwa JeremiahChakaya Muhwa Jeremiah
Chakaya Muhwa Jeremiah
MNmembers of the Global Tuberculosis Network
members of the Global Tuberculosis Network
The continuous flow of new research articles on MDR-TB diagnosis, treatment, prevention and rehabilitation requires frequent update of existing guidelines. This review is aimed at providing clinicians and public health staff with an updated and easy-to-consult document arising from consensus of Global Tuberculosis Network (GTN) experts. The core published documents and guidelines have been reviewed, including the recently published MDR-TB WHO rapid advice and ATS/CDC/ERS/IDSA guidelines. After a rapid review of epidemiology and risk factors, the clinical priorities on MDR-TB diagnosis (including whole genome sequencing and drug-susceptibility testing interpretations) and treatment (treatment design and management, TB in children) are discussed. Furthermore, the review comprehensively describes the latest information on contact tracing and LTBI management in MDR-TB contacts, while providing guidance on post-treatment functional evaluation and rehabilitation of TB sequelae, infection control and other public health priorities.

7 May 2016 in Current Fungal Infection Reports
Verified
Journal Article
Open access
PDF file
BDBart G. J. Dekkers
Bart G. J. Dekkers
MBMartijn Bakker
Martijn Bakker
KEKim C. M. van der Elst
Kim C. M. van der Elst
MSMarieke G. G. Sturkenboom
Marieke G. G. Sturkenboom
AVAnette Veringa
Anette Veringa
JAJan-Willem C Alffenaar
Jan-Willem C Alffenaar
Posaconazole is a second-generation triazole agent with a potent and broad antifungal activity. In addition to the oral suspension, a delayed-release tablet and intravenous formulation with improved pharmacokinetic properties have been introduced recently. Due to the large interindividual and intraindividual variation in bioavailability and drug-drug interactions, therapeutic drug monitoring (TDM) is advised to ensure adequate exposure and improve clinical response for posaconazole. Here, we highlight and discuss the most recent findings on pharmacokinetics and pharmacodynamics of posaconazole in the setting of prophylaxis and treatment of fungal infections and refer to the challenges associated with TDM of posaconazole.

6 September 2016 in Journal of Antimicrobial Chemotherapy
Verified
Journal Article
Open access
PDF file
AVAnette Veringa
Anette Veringa
MAMendy ter Avest
Mendy ter Avest
LSLambert F. R. Span
Lambert F. R. Span
EHEdwin R. van Den Heuvel
Edwin R. van Den Heuvel
Daniel Johannes TouwDaniel Johannes Touw
Daniel Johannes Touw
JAJan-Willem C Alffenaar
Jan-Willem C Alffenaar
During an infection or inflammation, several drug-metabolizing enzymes in the liver are down-regulated, including cytochrome P450 iso-enzymes. Since voriconazole is extensively metabolized by cytochrome P450 iso-enzymes, the metabolism of voriconazole can be influenced during inflammation via reduced clearance of the drug, resulting in higher voriconazole trough concentrations. To investigate prospectively the influence of inflammation on voriconazole metabolism and voriconazole trough concentrations. A prospective observational study was performed at the University Medical Center Groningen. Patients were eligible for inclusion if they were ≥18 years old and treated with voriconazole. Voriconazole and voriconazole-N-oxide concentrations were determined in discarded blood samples. To determine the degree of inflammation, C-reactive protein (CRP) concentrations were used. Subsequently, a longitudinal data analysis was performed to assess the effect of inflammation on the metabolic ratio and voriconazole trough concentration. Thirty-four patients were included. In total 489 voriconazole trough concentrations were included in the longitudinal data analysis. This analysis showed that inflammation, reflected by CRP concentrations, significantly influenced the metabolic ratio, voriconazole trough concentration and voriconazole-N-oxide concentration (all P < 0.001), when corrected for other factors that could influence voriconazole metabolism. The metabolic ratio was decreased by 0.99229N and the voriconazole-N-oxide concentration by 0.99775N, while the voriconazole trough concentration was increased by 1.005321N, where N is the difference in CRP units (in mg/L). This study shows that voriconazole metabolism is decreased during inflammation, resulting in higher voriconazole trough concentrations. Therefore, frequent monitoring of voriconazole serum concentrations is recommended during and following severe inflammation.

23 February 2022 in Journal of Medical Internet Research
Verified
Journal Article
Open access
ARAbdurahman Ridho
Abdurahman Ridho
SASofa Dewi Alfian
Sofa Dewi Alfian
Job van BovenJob van Boven
Job van Boven
Jutti LevitaJutti Levita
Jutti Levita
EAEsin AKI-YALCIN
Esin AKI-YALCIN
IPIvan Surya Pradipta
Ivan Surya Pradipta
Background: Nonadherence to medication in tuberculosis (TB) hampers optimal treatment outcomes. Digital health technology (DHT) seems to be a promising approach to managing problems of nonadherence to medication and improving treatment outcomes. Objective: This paper systematically reviews the effect of DHT in improving medication adherence and treatment outcomes in patients with TB. Methods: A literature search in PubMed and Cochrane databases was conducted. Randomized controlled trials (RCTs) that analyzed the effect of DHT interventions on medication adherence outcomes (treatment completion, treatment adherence, missed doses, and noncompleted rate) and treatment outcomes (cure rate and smear conversion) were included. Adult patients with either active or latent TB infection were included. The Jadad score was used for evaluating the study quality. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline was followed to report study findings. Results: In all, 16 RCTs were selected from 552 studies found, and 6 types of DHT interventions for TB were identified: 3 RCTs examined video directly observed therapy (VDOT), 1 examined video-observed therapy (VOT), 1 examined an ingestible sensor, 1 examined phone call reminders, 2 examined medication monitor boxes, and 8 examined SMS text message reminders. The outcomes used were treatment adherence, including treatment completion, treatment adherence, missed dose, and noncompleted rate, as well as clinical outcomes, including cure rate and smear conversion. In treatment completion, 4 RCTs (VDOT, VOT, ingestible sensor, SMS reminder) found significant effects, with odds ratios and relative risks (RRs) ranging from 1.10 to 7.69. Treatment adherence was increased in 1 study by SMS reminders (RR 1.05; 95% CI 1.04-1.06), and missed dose was reduced in 1 study by a medication monitor box (mean ratio 0.58; 95% CI 0.42-0.79). In contrast, 3 RCTs of VDOT and 3 RCTs of SMS reminders did not find significant effects for treatment completion. Moreover, no improvement was found in treatment adherence in 1 RCT of VDOT, missed dose in 1 RCT of SMS reminder, and noncompleted rate in 1 RCT of a monitor box, and 2 RCTs of SMS reminders. For clinical outcomes such as cure rate, 2 RCTs reported that phone calls (RR 1.30; 95% CI 1.07-1.59) and SMS reminders (OR 2.47; 95% CI 1.13-5.43) significantly affected cure rates. However, 3 RCTs found that SMS reminders did not have a significant impact on cure rate or smear conversion. Conclusions: It was found that DHT interventions can be a promising approach. However, the interventions exhibited variable effects regarding effect direction and the extent of improving TB medication adherence and clinical outcomes. Developing DHT interventions with personalized feedback is required to have a consistent and beneficial effect on medication adherence and outcomes among patients with TB.

27 June 2024 in Medical Mycology
Verified
Journal Article
Open access
PDF file
HKHannah Yejin Kim
Hannah Yejin Kim
TNThi Anh Nguyen
Thi Anh Nguyen
SKSarah Kidd
Sarah Kidd
JCJoshua Chambers
Joshua Chambers
Ana Alastruey-IzquierdoAna Alastruey-Izquierdo
Ana Alastruey-Izquierdo
JAJan-Willem C Alffenaar
Jan-Willem C Alffenaar
The World Health Organization (WHO) in 2022 developed a fungal priority pathogen list. Candida auris was ultimately ranked as a critical priority pathogen. PubMed and Web of Science were used to find studies published from 1 January 2011 to 18 February 2021, reporting on predefined criteria including: mortality, morbidity (i.e., hospitalization and disability), drug resistance, preventability, yearly incidence, and distribution/emergence. Thirty-seven studies were included in the final analysis. The overall and 30-day mortality rates associated with C. auris candidaemia ranged from 29% to 62% and 23% to 67%, respectively. The median length of hospital stay was 46–68 days, ranging up to 140 days. Late-onset complications of C. auris candidaemia included metastatic septic complications. Resistance rates to fluconazole were as high as 87%–100%. Susceptibility to isavuconazole, itraconazole, and posaconazole varied with MIC90 values of 0.06–1.0 mg/l. Resistance rates to voriconazole ranged widely from 28% to 98%. Resistance rates ranged between 8% and 35% for amphotericin B and 0%–8% for echinocandins. Over the last ten years, outbreaks due to C. auris have been reported in in all WHO regions. Given the outbreak potential of C. auris, the emergence and spread of MDR strains, and the challenges associated with its identification, and eradication of its environmental sources in healthcare settings, prevention and control measures based on the identified risk factors should be evaluated for their effectiveness and feasibility. Global surveillance studies could better inform the incidence rates and distribution patterns to evaluate the global burden of C. auris infections.