Integration of Physiologically-Based Pharmacokinetic Modeling into Early Clinical Development: An Investigation of the Pharmacokinetic Nonlinearity.

BMS-911543, a promising anticancer agent, exhibited time-dependent and dose-dependent nonlinear pharmacokinetics (PKs) in its first-in-human (FIH) study. Initial physiologically based pharmacokinetic (PBPK) modeling efforts using CYP1A2-mediated clearance kinetics were unsuccessful; however, further model analysis revealed that CYP1A2 time-dependent inhibition (TDI) and perhaps other factors could be keys to the nonlinearity. Subsequent experiments in human liver microsomes showed that the compound was a time-dependent inhibitor of CYP1A2 and were used to determine the enzyme inactivation parameter values. In addition, a rat tissue distribution study was conducted and human plasma samples were profiled to support the refinement of the PBPK model. It was concluded that the interplay between four BMS-911543 properties, namely, low solubility, saturation of the metabolizing enzyme CYP1A2, CYP1A2 TDI, and CYP1A2 induction likely resulted in the time-dependent and dose-dependent nonlinear PKs. The methodology of PBPK model-guided unmasking of compound properties can serve as a general practice for mechanistic understanding of a new compound's disposition.

Randomised controlled trial of the use of three dressing preparations in the management of chronic ulceration of the foot in diabetes.

OBJECTIVES: To determine the comparative effectiveness and cost-effectiveness of three dressing products, N-A, Inadine and Aquacel, for patients with diabetic foot ulcers, as well as the feasibility and consequences of less frequent dressing changes by health-care professionals. DESIGN: A multicentre, prospective, observer-blinded, parallel group, randomised controlled trial, with three arms. SETTING: Established expert multidisciplinary clinics for the management of diabetic foot ulcers across the UK. PARTICIPANTS: Patients over age 18 with type 1 or type 2 diabetes with a chronic (present for at least 6 weeks) full-thickness foot ulcer (on or below the malleoli) not penetrating to tendon, periosteum or bone, and with a cross-sectional area between 25 and 2500 mm(2). INTERVENTIONS: Participants were randomised 1:1:1 to treatment with one of N-A (a non-adherent, knitted, viscose filament gauze), Inadine (an iodine-impregnated dressing), both traditional dressings, or Aquacel, a newer product. MAIN OUTCOME MEASURES: The primary outcome measure was the number of ulcers healed in each group at week 24. Secondary measures included time to healing, new ulcerations, major and minor amputations, and episodes of secondary infection. RESULTS: A total of 317 patients were randomised. After 88 withdrawals, 229 remained evaluable. A greater proportion of smaller (25-100 mm(2) ulcers healed within the specified time (48.3% versus 37.3%; p = 0.048). There was, however, no difference between the three dressings in terms of percentage healed by 24 weeks, or in the mean time to healing, whether analysed on the basis of intention to treat (Inadine 44.4%, N-A 38.7%, Aquacel 44.7%; not significant) or per protocol (Inadine 55.2%, N-A 59.4%, Aquacel 63.0%; not significant). There was no difference in the quality of healing, as reflected in the incidence of recurrence within 12 weeks. Likewise, there was no difference in the incidence of adverse events, although a greater proportion of those randomised to the non-adherent dressings were withdrawn from the study (34.9% versus 29.1% Aquacel and 19.4% Inadine; p = 0.038). The only statistically significant difference found in the health economic analysis was the cost associated with the provision of dressings (mean cost per patient: N-A 14.85 pounds, Inadine 17.48 pounds, Aquacel 43.60 pounds). The higher cost of Aquacel was not offset by the fewer dressings required. There was no difference in measures of either generic or condition-specific measures of quality of life. However, there was a significant difference in the change in pain associated with dressing changes between the first and second visits, with least pain reported by those receiving non-adherent dressings (p = 0.012). There was no difference in the costs of professional time, and this may relate to the number of dressing changes undertaken by non-professionals. Fifty-one per cent of all participants had at least one dressing change undertaken by themselves or a non-professional carer, although this ranged from 22% to 82% between the different centres. CONCLUSIONS: As there was no difference in effectiveness, there is no reason why the least costly of the three dressings could not be used more widely across the UK National Health Service, thus generating potentially substantial savings. The option of involving patients and non-professional carers in changing dressings needs to be assessed more formally and could be associated with further significant reductions in health-care costs. TRIAL REGISTRATION: Current Controlled Trials ISRCTN78366977.

Benign intracranial hypertension associated with the withdrawal of a non-ergot dopamine agonist.

The cases are reported of two patients who developed benign intracranial hypertension after the withdrawal of the novel non-ergot derived dopamine agonist CV 205 502 (quinagolide).

A randomised controlled trial of insulin lispro given before or after meals in pregnant women with type 1 diabetes--the effect on glycaemic excursion.

In order to study the glucose excursion associated with pre- and postprandial administration a randomised controlled trial with patients randomised to receive insulin lispro (IL) immediately before or after a standardised meal was performed. Pregnant women with diabetes who were treated with IL as part of a basal bolus regime were asked to bring their own usual lunch and administer their own IL. Maternal glycaemia was monitored preprandially and then at 15-minute intervals for 3 hours following the first bite of lunch. Glucose excursions were calculated by subtracting the preprandial glucose level from the subsequent values at each time point. Each woman was invited to attend on four occasions. On two random occasions she was asked to administer her IL after completing her meal and on two occasions IL was administered immediately before her meal. Nine women completed a total of 27 meals (14 preprandial IL and 13 postprandial IL). There was no significant difference between the mean (SD) fasting values between the two groups, before 5.8 (2.8) and after 5.7 (2.0) mmol/l. At each time-point there was no significant difference between the mean blood glucose excursion in the two groups. No patient suffered a hypoglycaemic attack and there was no evidence of fetal compromise. In the two groups there was a marked similarity in the glycemic excursion following a standard meal, whether or not IL was given before or after eating. Postprandial administration of IL may increase the flexibility of IL usage in pregnant women with diabetes.