Rationale for the selection of dual primary endpoints in prevention studies of cognitively unimpaired individuals at genetic risk for developing symptoms of Alzheimer's disease.

Background: There is a critical need for novel primary endpoints designed to detect early and subtle changes in cognition in clinical trials targeting the asymptomatic (preclinical) phase of Alzheimer's disease (AD). The Alzheimer's Prevention Initiative (API) Generation Program, conducted in cognitively unimpaired individuals at risk of developing AD (e.g.

Dose-response analysis of ranibizumab as-needed regimens for visual improvement in patients with diabetic macular edema using a modelling approach.

Background: Ranibizumab and aflibercept are anti-vascular endothelial growth factor therapies for diabetic macular edema (DME) but have only been directly compared in one study: the Protocol T study, a 24-month randomized controlled trial which compared the safety and efficacy of three anti-VEGF agents (ranibizumab 0.3 mg, aflibercept 2.0 mg and bevacizumab 1.

Neovascular Age-Related Macular Degeneration: A Visual Acuity Model of Natural Disease Progression and Ranibizumab Treatment Effect.

Intravitreal ranibizumab is a first-line therapy for neovascular age-related macular degeneration (nAMD), but there is a need to optimize patient outcomes while minimizing treatment burden. Here, we developed an indirect response, nonlinear, mixed effects model of disease progression and drug effect in anti-vascular endothelial growth factor (VEGF) treatment-naïve patients. A total of 1,524 treatment-naïve patients and 29,754 visual acuity observations from the ANCHOR, MARINA, PIER, and EXCITE clinical trials informed the model.

A flexible Bayesian approach for modeling monotonic dose-response relationships in drug development trials.

Clinical trials often involve comparing 2-4 doses or regimens of an experimental therapy with a control treatment. These studies might occur early in a drug development process, where the aim might be to demonstrate a basic level of proof (the so-called proof of concept (PoC) studies), at a later stage, to help establish a dose or doses that should be used in phase III trials (dose-finding), or even in confirmatory studies, where the registration of several doses might be considered. When a small number of doses are examined, the ability to implement parametric modeling is somewhat limited.

Designing a non-inferiority study in kidney transplantation: a case study.

In organ transplantation, placebo-controlled clinical trials are not possible for ethical reasons, and hence non-inferiority trials are used to evaluate new drugs. Patients with a transplanted kidney typically receive three to four immunosuppressant drugs to prevent organ rejection. In the described case of a non-inferiority trial for one of these immunosuppressants, the dose is changed, and another is replaced by an investigational drug.

Bayesian models for subgroup analysis in clinical trials.

Background: In a pharmaceutical drug development setting, possible interactions between the treatment and particular baseline clinical or demographic factors are often of interest. However, the subgroup analysis required to investigate such associations remains controversial. Concerns with classical hypothesis testing approaches to the problem include low power, multiple testing, and the possibility of data dredging.

Imatinib plasma levels are correlated with clinical benefit in patients with unresectable/metastatic gastrointestinal stromal tumors.

PURPOSE To study the pharmacokinetics (PK) of imatinib (IM) in patients with advanced GI stromal tumors (GISTs) treated in a randomized phase II study and to explore the potential relationship between IM plasma levels and long-term clinical outcomes. PATIENTS AND METHODS Patients were randomly assigned to receive IM at 400 mg versus 600 mg daily. IM plasma levels were analyzed in a subset of patients (n = 73) for whom PK data on day 1 and at steady-state (SS, day 29) were available.

Confirmatory seamless phase II/III clinical trials with hypotheses selection at interim: applications and practical considerations.

Adaptive seamless phase II/III designs combine a phase II and a phase III study into one single confirmatory clinical trial. Several examples of such designs are presented, where the primary endpoint is binary, time-to-event or continuous. The interim adaptations considered include the selection of treatments and the selection of hypotheses related to a pre-specified subgroup of patients.

Confirmatory seamless phase II/III clinical trials with hypotheses selection at interim: general concepts.

Traditional drug development consists of a sequence of independent trials organized in different phases. Full development typically involves (i) a learning phase II trial and (ii) one or two confirmatory phase III trial(s). For example, in the phase II trials several doses of the new compound might be compared to a control and/or placebo with the goal of deciding whether to stop or continue development and, in the latter case, selecting one or two "best" doses to carry forward into the confirmatory phase.

Modelling and simulation in the development and use of anti-cancer agents: an underused tool?

To help identify the role of modelling and simulation in the development of anti-cancer agents, their main advantages and the obstacles to their rational use, an expert meeting was organized by COST B15. This manuscript presents a synthesis of views expressed at that meeting and indicates future directions. The manuscript also shows some examples where modelling and simulation have proven to be of relevant value in the drug development process for anti-cancer agents.

Imatinib pharmacokinetics in patients with gastrointestinal stromal tumour: a retrospective population pharmacokinetic study over time. EORTC Soft Tissue and Bone Sarcoma Group.

Imatinib pharmacokinetics (PK) may be affected by a number of factors that are related to the disease being treated and to the response of that disease to imatinib. Patients in the phase I and phase II trials conducted by the EORTC in patients with gastrointestinal stromal tumours (GISTs) and other sarcomas had detailed blood sampling for imatinib PK on day 1 and on day 29. Patients with GISTs also had repeat sampling, using a limited sampling strategy, after approximately 12 months on therapy.