Even more than in cognitive research applications, moving fMRI to the clinic and the drug development process requires the generation of stable and reliable signal changes. The performance characteristics of the fMRI paradigm constrain experimental power and may require different study designs (e.g., crossover vs. parallel groups), yet fMRI reliability characteristics can be strongly dependent on the nature of the fMRI task. The present study investigated both within-subject and group-level reliability of a combined three-task fMRI battery targeting three systems of wide applicability in clinical and cognitive neuroscience: an emotional (face matching), a motivational (monetary reward anticipation) and a cognitive (n-back working memory) task. A group of 25 young, healthy volunteers were scanned twice on a 3T MRI scanner with a mean test-retest interval of 14.6 days. FMRI reliability was quantified using the intraclass correlation coefficient (ICC) applied at three different levels ranging from a global to a localized and fine spatial scale: (1) reliability of group-level activation maps over the whole brain and within targeted regions of interest (ROIs); (2) within-subject reliability of ROI-mean amplitudes and (3) within-subject reliability of individual voxels in the target ROIs. Results showed robust evoked activation of all three tasks in their respective target regions (emotional task=amygdala; motivational task=ventral striatum; cognitive task=right dorsolateral prefrontal cortex and parietal cortices) with high effect sizes (ES) of ROI-mean summary values (ES=1.11-1.44 for the faces task, 0.96-1.43 for the reward task, 0.83-2.58 for the n-back task). Reliability of group level activation was excellent for all three tasks with ICCs of 0.89-0.98 at the whole brain level and 0.66-0.97 within target ROIs. Within-subject reliability of ROI-mean amplitudes across sessions was fair to good for the reward task (ICCs=0.56-0.62) and, dependent on the particular ROI, also fair-to-good for the n-back task (ICCs=0.44-0.57) but lower for the faces task (ICC=-0.02-0.16). In conclusion, all three tasks are well suited to between-subject designs, including imaging genetics. When specific recommendations are followed, the n-back and reward task are also suited for within-subject designs, including pharmaco-fMRI. The present study provides task-specific fMRI reliability performance measures that will inform the optimal use, powering and design of fMRI studies using comparable tasks.

Hepatitis C virus (HCV) infection is an issue of global concern, and studies are ongoing to identify new therapies that are both effective and safe. PF-4878691 is a Toll-like receptor 7 (TLR7) agonist modeled so as to dissociate its antiviral activities from its inflammatory activities. In a proof-of-mechanism study in healthy volunteers who received doses of 3, 6, and 9 mg of PF-4878691 twice a week for 2 weeks, PF-4878691 induced biomarkers of the immune and interferon (IFN) responses in a dose-dependent and dose-frequency-related manner. A novel finding was induction of TLR7 expression in vivo in response to PF-4878691, leading to an amplified biomarker response. A nonresponder at the 9-mg dose had a polymorphism in the IFN-α receptor 1 subunit (Val168Leu). Two subjects who had received 9-mg doses experienced serious adverse events (SAEs), characterized by flu-like symptoms, hypotension, and lymphopenia, leading to early termination of the study. TLR7 stimulation results in a pharmacologic response at levels commensurate with predicted antiviral efficacy, but these doses are associated with SAEs, raising concerns about the therapeutic window of this class of compounds for the treatment of HCV infection.

NCT01764594.

No abstract

In March 2006 a first-in-man trial took place using healthy volunteers involving the use of monoclonal antibodies. Within hours the subjects had suffered such adverse effects that they were admitted to intensive care at Northwick Park Hospital. In April 2006 the Secretary of State for Health announced the appointment of Professor (now Sir) Gordon Duff, who chairs the UK's Commission on Human Medicines, to chair a scientific expert group on phase 1 clinical trials. The group reported on December 7th, 2006 (Expert Scientific Group on Clinical Trials, 2006a). Clinical trials have a well-established regulatory basis both in the UK and worldwide. Trials have to be approved by the regulatory authority and are subject to a detailed protocol concerning, among other things, the study design and statistical analyses that will form the basis of the evaluation. In fact, a cornerstone of the regulatory framework is the statistical theory and methods that underpin clinical trials. As a result, the Royal Statistical Society established an expert group of its own to look in detail at the statistical issues that might be relevant to first-in-man studies. The group mainly comprised senior Fellows of the Society who had expert knowledge of the theory and application of statistics in clinical trials. However, the group also included an expert immunologist and clinicians to ensure that the interface between statistics and clinical disciplines was not overlooked. In addition, expert representation was sought from Statisticians in the Pharmaceutical Industry (PSI), an organization with which the Royal Statistical Society has very close links. The output from the Society's expert group is contained in this report. It makes a number of recommendations directed towards the statistical aspects of clinical trials. As such it complements the report by Professor Duff's group and will, I trust, contribute to a safer framework for first-in-man trials in the future. Tim Holt ("President, Royal Statistical Society") Copyright 2007 Royal Statistical Society.