No Evidence of a Drug-Drug Interaction Between Letermovir (MK-8228) and Mycophenolate Mofetil

Introduction: Letermovir (MK-8228) is a potent, oncedaily inhibitor of the cytomegalovirus (CMV) terminase complex that is being developed for the prophylaxis of CMV infection in transplant patients. This study evaluated the pharmacokinetic interactions, safety, and tolerability of letermovir when coadministered in healthy subjects with mycophenolate mofetil (MMF), which is the morpholinoethyl ester prodrug of mycophenolic acid (MPA). Methods: This was an open-label trial in 14 healthy female subjects that explored the pharmacokinetic parameters of a single 1 g oral dose of MMF administered alone on Day 1 and coadministered on Day 12 with 480 mg oral once-daily letermovir given on Day 5 and from Day 8 continued through Day 16. Letermovir PK was assessed at single dose (Day 5) and at steady state on Day 12 (with MMF) and Day 16 (alone following MMF washout). Results: Coadministration of 480 mg qd letermovir at steady state with a single dose of 1 g of MMF had no effect on the pharmacokinetics of MPA. The MPA AUC0-inf and Cmax geometric mean ratios (GMRs) [90% confidence interval] for the comparison (MMF with letermovir/ MMF alone) were 1.08 [0.96, 1.21] and 0.96 [0.81, 1.13], respectively. Coadministration of a single dose of 1 g MMF with 480 mg qd letermovir at steady state had no clinically meaningful effect on the pharmacokinetics of letermovir, with AUC0-24 and Cmax GMR of 1.18 [1.04, 1.32] and 1.11 [0.93, 1.34], respectively. The letermovir geometric mean accumulation ratio (Day 16/Day 5) and 95% CI were 1.13 [0.90, 1.42] for AUC0-24 and 1.01 [ 0.79, 1.28] f or Cmax, indicating that accumulation of letermovir when administered as daily doses is minimal. All related AEs were reported as mild in severity and resolved. Conclusions: Multiple-dose administration of 480 mg letermovir daily with a single dose of 1 g MMF was generally well tolerated by the healthy subjects in this study. Coadministration of letermovir and MMF had no clinically meaningful effect on the PK of letermovir or MPA. Letermovir and MMF may be coadministered without dose adjustment

Exercise therapy and cognitive behavioural therapy to improve fatigue, daily activity performance and quality of life in Postpoliomyelitis Syndrome: the protocol of the FACTS-2-PPS trial

Contains fulltext : 88661.pdf (publisher's version ) (Open Access)BACKGROUND: Postpoliomyelitis Syndrome (PPS) is a complex of late onset neuromuscular symptoms with new or increased muscle weakness and muscle fatigability as key symptoms. Main clinical complaints are severe fatigue, deterioration in functional abilities and health related quality of life. Rehabilitation management is the mainstay of treatment. Two different therapeutic interventions may be prescribed (1) exercise therapy or (2) cognitive behavioural therapy (CBT). However, the evidence on the effectiveness of both interventions is limited. The primary aim of the FACTS-2-PPS trial is to study the efficacy of exercise therapy and CBT for reducing fatigue and improving activities and quality of life in patients with PPS. Additionally, the working mechanisms, patients' and therapists' expectations of and experiences with both interventions and cost-effectiveness will be evaluated. METHODS/DESIGN: A multi-centre, single-blinded, randomized controlled trial will be conducted. A sample of 81 severely fatigued patients with PPS will be recruited from 3 different university hospitals and their affiliate rehabilitation centres. Patients will be randomized to one of three groups i.e. (1) exercise therapy + usual care, (2) CBT + usual care, (3) usual care. At baseline, immediately post-intervention and at 3- and 6-months follow-up, fatigue, activities, quality of life and secondary outcomes will be assessed. Costs will be based on a cost questionnaire, and statistical analyses on GEE (generalized estimated equations). Analysis will also consider mechanisms of change during therapy. A responsive evaluation will be conducted to monitor the implementation process and to investigate the perspectives of patients and therapists on both interventions. DISCUSSION: A major strength of the FACTS-2-PPS study is the use of a mixed methods design in which a responsive and economic evaluation runs parallel to the trial. The results of this study will generate new evidence for the rehabilitation treatment of persons with PPS. TRIAL REGISTRATION: Dutch Trial Register NTR1371

Suppression of Autophagy Dysregulates the Antioxidant Response and Causes Premature Senescence of Melanocytes

YesAutophagy is the central cellular mechanism for delivering organelles and cytoplasm to lysosomes for degradation and recycling of their molecular components. To determine the contribution of autophagy to melanocyte (MC) biology, we inactivated the essential autophagy gene Atg7 specifically in MCs using the Cre-loxP system. This gene deletion efficiently suppressed a key step in autophagy, lipidation of microtubule-associated protein 1 light chain 3 beta (LC3), in MCs and induced slight hypopigmentation of the epidermis in mice. The melanin content of hair was decreased by 10–15% in mice with autophagy-deficient MC as compared with control animals. When cultured in vitro, MCs from mutant and control mice produced equal amounts of melanin per cell. However, Atg7-deficient MCs entered into premature growth arrest and accumulated reactive oxygen species (ROS) damage, ubiquitinated proteins, and the multi-functional adapter protein SQSTM1/p62. Moreover, nuclear factor erythroid 2–related factor 2 (Nrf2)–dependent expression of NAD(P)H dehydrogenase, quinone 1, and glutathione S-transferase Mu 1 was increased, indicating a contribution of autophagy to redox homeostasis in MCs. In summary, the results of our study suggest that Atg7-dependent autophagy is dispensable for melanogenesis but necessary for achieving the full proliferative capacity of MCs

Analysis of benzo[a]pyrene metabolites formed by rat hepatic microsomes using high pressure liquid chromatography: optimization of the method

A simple and sensitive method was developed to separate the carcinogenic polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (BaP), and six of its oxidation metabolites generated by rat hepatic microsomes enriched with cytochrome P450 (CYP) 1A1, by high pressure liquid chromatography (HPLC). The HPLC method, using an acetonitrile/water gradient as mobile phase and UV detection, provided appropriate separation and detection of both mono- and di-hydroxylated metabolites of BaP as well as BaP diones formed by rat hepatic microsomes and the parental BaP. In this enzymatic system, 3-hydroxy BaP, 9-hydroxy BaP, BaP-4,5-dihydrodiol, BaP-7,8-dihydrodiol, BaP-9,10-dihydrodiol and BaP-dione were generated. Among them the mono-hydroxylated BaP metabolite, 3-hydroxy BaP followed by di-hydroxylated BaP products, BaP-7,8-dihydrodiol and BaP-9,10-dihydrodiol, predominated, while BaP-dione was a minor metabolite. This HPLC method will be useful for further defining the roles of the CYP1A1 enzyme with both in vitro and in vivo models in understanding its real role in activation and detoxification of BaP

Enhancement of DNA repair using topical T4 endonuclease V does not inhibit melanoma formation in cdk4R24C/R24C/Tyr-NrasQ61K mice following neonatal UVR

To further investigate the use of DNA repair-enhancing agents for skin cancer prevention, we treated Cdk4R24C/R24C/NrasQ61K mice topically with the T4 endonuclease V DNA repair enzyme (known as Dimericine) immediately prior to neonatal ultraviolet radiation (UVR) exposure, which has a powerful effect in exacerbating melanoma development in the mouse model. Dimericine has been shown to reduce the incidence of basal-cell and squamous cell carcinoma. Unexpectedly, we saw no difference in penetrance or age of onset of melanoma after neonatal UVR between Dimericine-treated and control animals, although the drug reduced DNA damage and cellular proliferation in the skin. Interestingly, epidermal melanocytes removed cyclobutane pyrimidine dimers (CPDs) more efficiently than surrounding keratinocytes. Our study indicates that neonatal UVR-initiated melanomas may be driven by mechanisms other than solely that of a large CPD load and/or their inefficient repair. This is further suggestive of different mechanisms by which UVR may enhance the transformation of keratinocytes and melanocytes