Leflunomide for Inflammatory Arthritis in End-Stage Renal Disease on Peritoneal Dialysis: A Pharmacokinetic and Pharmacogenetic Study

Assessment of interactions and dosage recommendations of synthetic DMARDs-Evidence-based and consensus-based recommendations based on a systematic literature search

Conventional synthetic (cs) and targeted synthetic (ts) disease-modifying antirheumatic drugs (DMARD) have potential interactions with a multitude of drugs. Furthermore, they sometimes have a lower therapeutic index, particularly in cases of limited organ functions. The aim of this work was to establish evidence-based recommendations on the therapeutic use of DMARDs in the context of drug interactions and dosage recommendations. A systematic literature search was carried out on the issue of drug interactions and dosages in cases of patients with limited kidney function and higher age and suffering from rheumatoid arthritis. A total of 2756 scientific publications were screened and 154 selected of which 68 were scrutinized in detail. Furthermore, the respective product information was also analyzed. A multitude of possible interactions of synthetic DMARDs with different drugs were detected, which were then assessed with respect to the clinical significance and consequences. A consensus process led to making recommendations with which the interactions were classified: A: dangerous combination, B: avoid combination (if possible, pausing DMARD treatment), C: possible combination requiring increased monitoring and potential adjustments in dosage and D: pharmacological interaction without relevance in DMARD standard doses. Apart from that dosage recommendations were established for each csDMARD and tsDMARD depending on kidney function and age. There are 3 primary recommendations and 11 core recommendations on interactions and dosages of csDMARDs and tsDMARDs meant as a practical help for therapeutic decision making and to improve safety in the treatment of rheumatoid arthritis.

Rheumatoid arthritis - medication dosage in chronic kidney disease

Renal failure in the course of rheumatoid arthritis (RA) is a consequence of many factors, including drug-induced nephrotoxicity, comorbidities and chronic inflammation. Contemporary treatment strategies have reduced the incidence of renal failure in the population of RA patients. However, it remains a problem for approximately 25% of patients. Therefore, special attention should be paid to the potential need for dosage modifications of administered medications. Many drugs used in the therapy of rheumatic diseases have not been thoroughly studied for their safety in patients with reduced glomerular filtration, resulting in limited data in this area. The establishment of precise, transparent, and consistent dosage recommendations for antirheumatic drugs in chronic kidney disease would significantly facilitate the care of patients with RA. The following review provides a general summary of the available knowledge regarding the dosage of rheumatic medications in renal insufficiency and aims to highlight the need for further research in this area.

[Assessment of interactions and dosage recommendations of synthetic DMARDs-Evidence-based and consensus-based recommendations based on a systematic literature search]

Conventional synthetic (cs) and targeted synthetic (ts) disease-modifying antirheumatic drugs (DMARD) have potential interactions with a multitude of drugs. Furthermore, they sometimes have a lower therapeutic index, particularly in cases of limited organ functions. The aim of this work was to establish evidence-based recommendations on the therapeutic use of DMARDs in the context of drug interactions and dosage recommendations. A systematic literature search was carried out on the issue of drug interactions and dosages in cases of patients with limited kidney function and higher age and suffering from rheumatoid arthritis. A total of 2756 scientific publications were screened and 154 selected of which 68 were scrutinized in detail. Furthermore, the respective specialist subject information was also analyzed. A multitude of possible interactions of synthetic DMARDs with different drugs were detected, which were then assessed with respect to the clinical significance and consequences. A consensus process led to making recommendations with which the interactions were classified: A: dangerous combination, B: avoid combination (if possible, pausing DMARD treatment), C: possible combination requiring increased monitoring and potential adjustments in dosage and D: pharmacological interaction without relevance in DMARD standard doses. Apart from that dosage recommendations were established for each csDMARD and tsDMARD depending on kidney function and age. There are 3 primary recommendations and 11 core recommendations on interactions and dosages of csDMARDs and tsDMARDs meant as a practical help for therapeutic decision making and to improve safety in the treatment of rheumatoid arthritis.

Clinical Pharmacokinetic Monitoring of Leflunomide in Renal Transplant Recipients with BK Virus Reactivation: A Review of the Literature

Leflunomide is an immunosuppressive drug with in vitro and initial observational evidence of antiviral activity against BK virus (BKV), a pathogen that causes opportunistic infection upon reactivation in renal transplant recipients. Leflunomide is considered an ancillary option to immunosuppression reduction in the management of BKV reactivation. Plasma or blood concentrations of teriflunomide, the active metabolite of leflunomide, are commonly monitored because of high leflunomide doses being used, known inter-individual variability in pharmacokinetics, and hepatotoxicity risk. However, the utility of clinical pharmacokinetic monitoring for leflunomide is as yet unclear. A literature search of MEDLINE (1946-December 2016), EMBASE (1974-December 2016), the CENTRAL database, and Google Scholar was performed to identify relevant English-language articles. Further articles were identified from references in relevant literature. A previously published 9-step decision-making algorithm was used to assess the available literature and determine the utility of clinical pharmacokinetic monitoring for leflunomide. Teriflunomide is readily measurable in the plasma or blood, but a clear relationship between concentration and efficacy or toxicity is lacking, and its therapeutic range is not well-established. Efficacy and toxicity endpoints such as renal function and BKV clearance can be readily assessed without measuring teriflunomide concentrations. Pharmacokinetic parameters are affected by genetic polymorphisms in cytochrome P450 CYP2C19 and ABCG2 genes. Therefore, routine clinical pharmacokinetic monitoring of leflunomide cannot be recommended based on current available evidence. However, it may provide clinical benefit in difficult situations when patients demonstrate a lack of therapeutic response or exhibit signs of drug toxicity.

Fingerprinting of neurotoxic compounds using a mouse embryonic stem cell dual luminescence reporter assay

Identification of neurotoxic drugs and environmental chemicals is an important challenge. However, only few tools to address this topic are available. The aim of this study was to develop a neurotoxicity/developmental neurotoxicity (DNT) test system, using the pluripotent mouse embryonic stem cell line CGR8 (ESCs). The test system uses ESCs at two differentiation stages: undifferentiated ESCs and ESC-derived neurons. Under each condition, concentration–response curves were obtained for three parameters: activity of the tubulin alpha 1 promoter (typically activated in early neurons), activity of the elongation factor 1 alpha promoter (active in all cells), and total DNA content (proportional to the number of surviving cells). We tested 37 compounds from the ESNATS test battery, which includes polypeptide hormones, environmental pollutants (including methylmercury), and clinically used drugs (including valproic acid and tyrosine kinase inhibitors). Different classes of compounds showed distinct concentration–response profiles. Plotting of the lowest observed adverse effect concentrations (LOAEL) of the neuronal promoter activity against the general promoter activity or against cytotoxicity, allowed the differentiation between neurotoxic/DNT substances and non-neurotoxic controls. Reporter activity responses in neurons were more susceptible to neurotoxic compounds than the reporter activities in ESCs from which they were derived. To relate the effective/toxic concentrations found in our study to relevant in vivo concentrations, we used a reverse pharmacokinetic modeling approach for three exemplary compounds (teriflunomide, geldanamycin, abiraterone). The dual luminescence reporter assay described in this study allows high-throughput, and should be particularly useful for the prioritization of the neurotoxic potential of a large number of compounds.

Individualization of leflunomide dosing in rheumatoid arthritis patients

Leflunomide is largely considered to be a second-line treatment option for rheumatoid arthritis (RA). Those who fail to respond, tend to progress to treatment with expensive biological agents, which can also be associated with serious toxicities. Optimizing leflunomide treatment to meet the needs of individuals would hence be beneficial in terms of patient outcomes and health care expenditure. In this respect, therapeutic drug monitoring (TDM) may be useful, as plasma concentrations of leflunomide's active metabolite, teriflunomide, correlate with response to treatment, but are highly variable between patients. A number of pharmacogenetic markers have also been identified that influence response and toxicity. Incorporation of these findings into clinical practice could facilitate more efficient use of leflunomide.