Simulating the Impact of Elevated Levels of Interleukin-6 on the Pharmacokinetics of Various CYP450 Substrates in Patients with Neuromyelitis Optica or Neuromyelitis Optica Spectrum Disorders in Different Ethnic Populations.

A physiologically based pharmacokinetic (PBPK) model was used to simulate the impact of elevated levels of interleukin (IL)-6 on the exposure of several orally administered cytochrome P450 (CYP) probe substrates (caffeine, S-warfarin, omeprazole, dextromethorphan, midazolam, and simvastatin). The changes in exposure of these substrates in subjects with rheumatoid arthritis (and hence elevated IL-6 levels) compared with healthy subjects were predicted with a reasonable degree of accuracy. The PBPK model was then used to simulate the change in oral exposure of the probe substrates in North European Caucasian, Chinese, and Japanese population of patients with neuromyelitis optica (NMO) or NMO spectrum disorder with elevated plasma IL-6 levels (up to 100 pg/mL). Moderate interactions [mean AUC fold change, ≤ 2.08 (midazolam) or 2.36 (simvastatin)] was predicted for CYP3A4 probe substrates and weak interactions (mean AUC fold change, ≤ 1.29-1.97) were predicted for CYP2C19, CYP2C9, and CYP2D6 substrates. No notable interaction was predicted with CYP1A2. Although ethnic differences led to differences in simulated exposure for some of the probe substrates, there were no marked differences in the predicted magnitude of the change in exposure following IL-6-mediated suppression of CYPs. Decreased levels of serum albumin (as reported in NMO patients) had little impact on the magnitude of the simulated IL-6-mediated drug interactions. This PBPK modeling approach allowed us to leverage knowledge from different disease and ethnic populations to make predictions of cytokine-related DDIs in a rare disease population where actual clinical studies would otherwise be difficult to conduct.

Safety and efficacy of olesoxime in patients with type 2 or non-ambulatory type 3 spinal muscular atrophy: a randomised, double-blind, placebo-controlled phase 2 trial.

BACKGROUND: Spinal muscular atrophy (SMA) is a progressive motor neuron disease causing loss of motor function and reduced life expectancy, for which limited treatment is available. We investigated the safety and efficacy of olesoxime in patients with type 2 or non-ambulatory type 3 SMA. METHODS: This randomised, double-blind, placebo-controlled, phase 2 study was done in 22 neuromuscular care centres in Belgium, France, Germany, Italy, Netherlands, Poland, and the UK. Safety and efficacy of olesoxime were assessed in patients aged 3-25 years with genetically confirmed type 2 or non-ambulatory type 3 SMA. A centralised, computerised randomisation process allocated patients (2:1 with stratification by SMA type and centre) to receive olesoxime (10 mg/kg per day) in an oral liquid suspension or placebo for 24 months. Patients, investigators assessing outcomes, and sponsor study personnel were masked to treatment assignment. The primary outcome measure was change from baseline compared with 24 months between the two treatment groups in functional domains 1 and 2 of the Motor Function Measure (MFM D1 + D2) assessed in the full analysis population. A shorter, 20-item version of the MFM, which was specifically adapted for young children, was used to assess patients younger than 6 years. Safety was assessed in all patients who received one or more doses of the study drug. The trial is registered with ClinicalTrials.gov, number NCT01302600. FINDINGS: The trial was done between Nov 18, 2010, and Oct 9, 2013. Of 198 patients screened, 165 were randomly assigned to olesoxime (n=108) or placebo (n=57). Five patients in the olesoxime group were not included in the primary outcome analysis because of an absence of post-baseline assessments. The change from baseline to month 24 on the primary outcome measure was 0·18 for olesoxime and -1·82 for placebo (treatment difference 2·00 points, 96% CI -0·25 to 4·25, p=0·0676). Olesoxime seemed to be safe and generally well tolerated, with an adverse event profile similar to placebo. The most frequent adverse events in the olesoxime group were pyrexia (n=34), cough (n=32), nasopharyngitis (n=25), and vomiting (n=25). There were two patient deaths (one in each group), but these were not deemed to be related to the study treatment. INTERPRETATION: Olesoxime was safe at the doses studied, for the duration of the trial. Although the primary endpoint was not met, secondary endpoints and sensitivity analyses suggest that olesoxime might maintain motor function in patients with type 2 or type 3 SMA over a period of 24 months. Based on these results, olesoxime might provide meaningful clinical benefits for patients with SMA and, given its mode of action, might be used in combination with other drugs targeting other mechanisms of disease, although additional evidence is needed. FUNDING: AFM Téléthon and Trophos SA.

Effect of gastric pH on erlotinib pharmacokinetics in healthy individuals: omeprazole and ranitidine.

The aim of this study was to evaluate the effect of coadministration of acid-reducing agents on the pharmacokinetic exposure of orally administered epidermal growth factor receptor inhibitor erlotinib, a drug that displays pH-dependent solubility. Two studies were conducted, the first with the proton pump inhibitor omeprazole and the second with the H2-receptor antagonist ranitidine. Twenty-four healthy male and female volunteers were enrolled in each study. Erlotinib was administered as a single oral 150 mg dose on day 1. After the washout a subsequent study period evaluated 150 mg erlotinib administered with the acid-reducing agent. Omeprazole (40 mg once daily) was given on days 11-14, concomitantly with erlotinib on day 15, and for two additional days (days 16-17). In the ranitidine study, on day 13, participants were randomized to either concomitant dosing (treatment B) or staggered administration (treatment C) of erlotinib and ranitidine and crossed over to the other treatment starting on day 27. For treatment B, ranitidine (300 mg once daily) was administered in the morning for 5 days, 2 h before erlotinib. For treatment C, ranitidine was administered as a divided dose (150 mg twice daily) for 5 days, with erlotinib given 10 h after the previous evening dose and 2 h before the next ranitidine morning dose. Plasma samples were obtained for determination of the concentrations of erlotinib and its metabolite OSI-420, following each erlotinib dose. All participants were monitored for safety and tolerability. The geometric mean ratios of AUC0-∞ and Cmax for erlotinib and AUC0-last and Cmax for OSI-420 were substantially decreased when erlotinib was dosed with omeprazole. The estimated mean ratio (90% confidence interval) for erlotinib was 0.54 (0.49-0.59) for AUC0-∞ and 0.39 (0.32-0.48) for Cmax. For OSI-420, the estimated mean ratio was 0.42 (0.37-0.48) for AUC0-last and 0.31 (0.24-0.41) for Cmax. AUC0-∞ and Cmax for erlotinib were substantially decreased by 33 and 54%, respectively, upon coadministration with ranitidine, but the decrease was only 15 and 17% when ranitidine and erlotinib were given staggered. Similar results were observed for the metabolite OSI-420. Erlotinib was generally well-tolerated alone or in combination with omeprazole or ranitidine. Erlotinib pharmacokinetic exposure was substantially reduced upon coadministration with omeprazole and ranitidine, but not when administered with a staggered dosing approach to ranitidine. Therefore, it is recommended that the concomitant use of erlotinib with proton pump inhibitors be avoided. If treatment with an H2-receptor antagonist such as ranitidine is required, erlotinib must be administered 10 h after the H2-receptor antagonist dosing and at least 2 h before the next dose of the H2-receptor antagonist.

Absence of an interaction between iron and mycophenolate mofetil absorption.

AIM: To determine whether concomitant iron affects the absorption of mycophenolate mofetil. METHODS: An open-label, single centre, randomized, crossover trial was conducted in 16 healthy males. Fasting subjects received mycophenolate mofetil alone (treatment A) or co-administered with iron (treatment B). RESULTS: The mycophenolic acid AUC(0,24 h) for treatments A and B were 42.5 +/- 10.5 and 44.7 +/- 12.4 microg ml(-1) h, respectively. anova modelling showed the relative bioavailability of mycophenolate mofetil to be similar for the two treatments (90% confidence interval 0.92, 1.19). CONCLUSIONS: There was no interaction between mycophenolate mofetil and iron supplements administered concomitantly to healthy fasting subjects.

Equivalent pharmacokinetics of mycophenolate mofetil in African-American and Caucasian male and female stable renal allograft recipients.

African-American (AA) renal transplant recipients require higher doses of mycophenolate mofetil (MMF) than Caucasians. A hypothesized pharmacokinetic (PK) difference was tested in stable renal transplant recipients. Whole blood was collected before, and 20, 40 and 75 min, and 2, 3, 4, 6, 8 and 12 h after the MMF dose. Mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) were analyzed using HPLC. Analysis of variance was performed for the primary end-points of dose-adjusted PK parameters AUC0-12 and Cmax of MPA using log-transformed values. Differences between races and genders were estimated: 90% confidence intervals (CI) were calculated. Back-transformation gave estimates of the race and gender ratio and their CI. Equivalence of the groups was determined if the 90% confidence limits were included in the interval (0.80, 1.25). The calculated PK parameters were comparable among the four subgroups (Caucasian, AA, Male, Female). The 90% CIs for the ratio of dose-adjusted AUC0-12 of MPA between races were between 89.7 and 112.9%. There were no race, gender or race-by-gender effects (p-values = 0.196) nor differences between diabetics and nondiabetics. This study demonstrates that dosing requirement for MMF in AA and Caucasians is unlikely to be related to different exposures to MPA.