Advanced Methods for Dose and Regimen Finding During Drug Development: Summary of the EMA/EFPIA Workshop on Dose Finding (London 4-5 December 2014)

Inadequate dose selection for confirmatory trials is currently still one of the most challenging issues in drug development, as illustrated by high rates of late‐stage attritions in clinical development and postmarketing commitments required by regulatory institutions. In an effort to shift the current paradigm in dose and regimen selection and highlight the availability and usefulness of well‐established and regulatory‐acceptable methods, the European Medicines Agency (EMA) in collaboration with the European Federation of Pharmaceutical Industries Association (EFPIA) hosted a multistakeholder workshop on dose finding (London 4–5 December 2014). Some methodologies that could constitute a toolkit for drug developers and regulators were presented. These methods are described in the present report: they include five advanced methods for data analysis (empirical regression models, pharmacometrics models, quantitative systems pharmacology models, MCP‐Mod, and model averaging) and three methods for study design optimization (Fisher information matrix (FIM)‐based methods, clinical trial simulations, and adaptive studies). Pairwise comparisons were also discussed during the workshop; however, mostly for historical reasons. This paper discusses the added value and limitations of these methods as well as challenges for their implementation. Some applications in different therapeutic areas are also summarized, in line with the discussions at the workshop. There was agreement at the workshop on the fact that selection of dose for phase III is an estimation problem and should not be addressed via hypothesis testing. Dose selection for phase III trials should be informed by well‐designed dose‐finding studies; however, the specific choice of method(s) will depend on several aspects and it is not possible to recommend a generalized decision tree. There are many valuable methods available, the methods are not mutually exclusive, and they should be used in conjunction to ensure a scientifically rigorous understanding of the dosing rationale.

Model Evaluation of Continuous Data Pharmacometric Models: Metrics and Graphics

This article represents the first in a series of tutorials on model evaluation in nonlinear mixed effect models (NLMEMs), from the International Society of Pharmacometrics (ISoP) Model Evaluation Group. Numerous tools are available for evaluation of NLMEM, with a particular emphasis on visual assessment. This first basic tutorial focuses on presenting graphical evaluation tools of NLMEM for continuous data. It illustrates graphs for correct or misspecified models, discusses their pros and cons, and recalls the definition of metrics used.

Time for Quantitative Clinical Pharmacology: A Proposal for a Pharmacometrics Curriculum

A formal training program in pharmacometrics is essential to train clinical pharmacology scientists. A proposal is made for a pharmacometrics curriculum. The curriculum has components at the undergraduate, graduate and postgraduate levels.

Theophylline target concentration in severe airways obstruction - 10 or 20 mg/L? A randomised concentration-controlled trial

The optimal serum concentration of theophylline for the management of acute airways obstruction was evaluated by comparing the response to target concentrations at the extremes of the usual therapeutic range. 174 patients requiring intravenous theophylline were randomly assigned to a target concentration of 10 or 20 mg/L. Control of theophylline dosage using measured theophylline concentrations and evaluation of efficacy and toxicity was performed under double-blind conditions. 87 patients (50%) required hospital admission. Of these, 54 patients (62%) were followed throughout their hospital admission and reviewed at an outpatient clinic approximately 1 week after discharge. The duration of hospital stay, and rate and extent of improvement in peak expiratory flow rate were not different between the groups. There was significantly more toxicity in the 20 mg/L group. The initial target concentration for theophylline in the management of acute airway obstruction should be 10 mg/L under circumstances where concentration is used to control theophylline dosages.

Time and theophylline concentration help explain the recovery of peak flow following acute airways obstruction. Population analysis of a randomised concentration controlled trial

Peak expiratory flow rate, adverse effects and serum theophylline concentration were measured during treatment of episodes of severe airways obstruction. 174 patients were randomised to target theophylline concentrations of 10 mg/L or 20 mg/L. The recovery of peak flow rate towards normal values was explicable in terms of time and theophylline concentration using semiparametric and parametric nonlinear regression models. In the absence of theophylline, recovery takes place with a half-time of 16 hours. Theophylline is less effective in achieving recovery than the passage of time but achieves 50% of possible recovery at a concentration of 11 mg/L. The action of theophylline is most marked at the start of treatment. It may no longer have important beneficial effects after 72 hours. The incidence of adverse effects increased at theophylline concentrations > 20 mg/L.

Effects of antiarrhythmic drugs on atrioventricular conduction in patients with acute myocardial infarction

Three hundred fifty-eight of 429 (83%) consecutive patients with acute myocardial infarction (MI) and a normal PR interval received various antiarrhythmic drugs (AD), including lidocaine and/or procainamide, quinidine, digoxin, propranolol or disopyramide. There was no significant difference in the incidence of progression to any degree of atrioventricular (AV) block or to higher degrees of AV block (Mobitz II or third-degree AV block) between those treated and not treated with AD: 38 of 358 (11%) and six of 358 (1.7%) with AD vs 11 of 71 (15%) and two of 71 (2.8%) in the untreated group, respectively. Similarly, there was no significant difference in progression between treated and untreated patients with anterior MI, 14 of 144 (10%) vs five of 32 (16%); inferior MI, 21 of 111 (19%) vs five of 26 (19%), or subendocardial MI, three of 103 (3%) vs one of 12 (8%). Bundle branch block (BBB) (without AV block) was initially present in 89 of 249 (21%). The incidence of AV block (seven of 24, 30%) was higher in treated patients with newly acquired BBB (27 patients) than in the untreated patients (none of three, p less than 0.05). The commonly used ADs did not adversely affect AV conduction in patients with acute MI with narrow QRS and either normal, first-degree, or Mobitz I AV block. Moreover, no subset of patients grouped by infarct location, specific AD used, or BBB (except perhaps for those with newly acquired BBB) appeared to be at risk of development of AV block during AD therapy.