David J. DeBrota

The responsiveness of the Hamilton Depression Rating Scale.

In clinical studies of antidepressants, the Hamilton Depression Rating Scale (HAMD) total score has been the gold standard instrument for establishing and comparing the efficacy of new treatments. However, the HAMD is a multidimensional measure, which may reduce its ability to detect differences between treatments, in particular, changes in core symptoms of depression. Two meta-analyses were conducted to compare the responsiveness of the HAMD total score with several published unidimensional subscale scores based upon core symptoms of depression. The first compared the above instruments ability to detect differences between fluoxetine and placebo across eight studies involving over 1600 patients. The second analysis involved four studies and over 1200 patients randomized to tricyclic antidepressants and placebo. In both meta-analyses, the unidimensional core subscales outperformed the HAMD total score at detecting treatment differences. The implications of this on sample sizes and power for clinical studies will be discussed. In fact, studies based on the observed effect sizes from the core subscales would require approximately one-third less patients than studies based on the HAMD total score. Effect sizes from each individual HAMD item will also be presented to help explain the differences in responsiveness between the scales.

Assessing and interpreting treatment effects in longitudinal clinical trials with missing data

Treatment effects are often evaluated by comparing change over time in outcome measures; however, valid analyses of longitudinal data can be problematic, particularly if some data are missing. For decades, the last observation carried forward (LOCF) approach has been a common method of handling missing data. Considerable advances in statistical methodology and our ability to implement those methods have been made in recent years. Thus, it is appropriate to reconsider analytic approaches for longitudinal data. This review examines the following from a clinical perspective: 1) the characteristics of missing data that influence analytic choices; 2) the attributes of common methods of handling missing data; and 3) the use of the data characteristics and the attributes of the various methods, along with empirical evidence, to develop a robust approach for the analysis and interpretation of data from longitudinal clinical trials. We propose that, in many settings, the primary efficacy analysis should use a repeated measures, likelihood-based, mixed-effects modeling approach, with LOCF used as a secondary, composite measure of efficacy, safety, and tolerability. We illustrate how repeated-measures analyses can be used to enhance decision-making, and we review the caveats that remain regarding the use of LOCF as a composite measure.

Rating the raters: Assessing the quality of Hamilton Rating Scale for depression clinical interviews in two industry-sponsored clinical drug trials

Objective: The quality of clinical interviews conducted in industry-sponsored clinical drug trials is an important but frequently overlooked variable that may influence the outcome of a study. We evaluated the quality of Hamilton Rating Scale for Depression (HAM-D) clinical interviews performed at baseline in 2 similar multicenter, randomized, placebo-controlled depression trials sponsored by 2 pharmaceutical companies. Methods: A total of 104 audiotaped HAM-D clinical interviews were evaluated by a blinded expert reviewer for interview quality using the Rater Applied Performance Scale (RAPS). The RAPS assesses adherence to a structured interview guide, clarification of and follow-up to patient responses, neutrality, rapport, and adequacy of information obtained. Results: HAM-D interviews were brief and cursory and the quality of interviews was below what would be expected in a clinical drug trial. Thirty-nine percent of the interviews were conducted in 10 minutes or less, and most interviews were rated fair or unsatisfactory on most RAPS dimensions. Conclusions: Results from our small sample illustrate that the clinical interview skills of raters who administered the HAM-D were below what many would consider acceptable. Evaluation and training of clinical interview skills should be considered as part of a rater training program.

Neurophysiologic Correlates of Side Effects in Normal Subjects Randomized to Venlafaxine or Placebo

Adverse events reported in the context of medication administration may be due to pharmacodynamic and/or nonpharmacodynamic effects (eg, nocebo phenomena). Neurophysiological substrates of side effects may be examined in placebo-controlled antidepressant treatment trials. We explored the relationship between side effects and regional neurophysiologic changes in normal subjects receiving a 1-week placebo lead-in followed by 4 weeks randomized treatment with placebo (n=15) or venlafaxine IR (n=17). Quantitative electroencephalographic (QEEG) cordance measures were obtained before and during treatment, and side effects were assessed weekly using semistructured interviews. Side effect burden, characterized as the mean number of side effects per postrandomization visit, correlated significantly with neurophysiologic changes in the antidepressant group but not the placebo group. Medication group side effects were negatively correlated with changes in prefrontal cordance at end of placebo lead-in (r=−0.67, p<0.003), at 2 weeks (r=−0.77, p<0.002), and at 4 weeks (r=−0.77, p<0.004) post randomization. After controlling for the prefrontal change at the end of placebo lead-in, postrandomization brain changes did not further explain side effect burden. Changes in prefrontal brain function associated with later antidepressant side effects were observed during placebo lead-in—prior to the administration of medication. Prefrontal brain function during brief placebo administration may help explain susceptibility to the development of antidepressant side effects. Results of these exploratory hypothesis-generating analyses should be considered tentative until replicated.

Changes in Brain Function during Administration of Venlafaxine or Placebo to Normal Subjects

Previous research has demonstrated neurophysiologic effects of antidepressants in depressed subjects. We evaluated neurophysiologic effects of venlafaxine in normal subjects. Healthy adults (n=32) received a 1-week placebo lead-in followed by 4 weeks randomized double-blind treatment with venlafaxine IR 150 mg. (n = 17) or placebo (n = 15). Brain function was examined using quantitative electroencephalographic (QEEG) power and theta cordance. Normal subjects receiving venlafaxine showed a decrease in theta-band cordance in the midline-and-right-frontal (MRF) region at 48 hours and at 1 week after randomization. Decreases in relative power also were seen in the MRF region; there were no significant changes in absolute power. These changes were significantly different from those in subjects receiving placebo. Changes in MRF cordance accurately identified treatment condition at 48 hours in 81.3% of subjects, and relative power from this region identified 60.7% of subjects. In conclusion, cordance may detect the pharmacological effects of antidepressant medication in normal subjects. Future studies should examine other classes of medication, as well as antidepressants with other mechanisms of action, to determine if cordance detects antidepressant medication effects in general in normal subjects.

An examination of 26,168 Hamilton Depression Rating Scale scores administered via interactive voice response across 17 randomized clinical trials.

Abstract: This article presents descriptive and psychometric data from 26,168 Hamilton Depression Rating Scale (HAM-D) scores administered via Interactive Voice Response (IVR) in 17 randomized clinical trials sponsored by 6 pharmaceutical companies. To provide evidence for construct validity, the IVR HAM-D scores before and after randomization are compared, and the change in the IVR HAM-D scores over time after randomization are examined. In addition, the evidence for the reliability of the IVR-administered HAM-D is presented. An examination of the distribution of first-time IVR HAM-Ds before randomization may provide useful information to researchers planning to use the IVR HAM-D as a screening tool for entry or to verify baseline severity in randomized clinical trials.

Pharmacokinetics and pharmacodynamics of the cathepsin S inhibitor, LY3000328, in healthy subjects

AIM The aim of this study was to assess the safety and tolerability, pharmacokinetics and pharmacodynamics of LY3000328 when administered as single escalating doses to healthy volunteers. METHODS This was a phase 1, placebo-controlled, dose escalation study with LY3000328 in 21 healthy male volunteers. Subjects were administered escalating LY3000328 doses up to 300 mg with food in this single dose study. Blood samples were collected at set times post-dose for the assessment of LY3000328 pharmacokinetics and the measurement of cathepsin S (CatS) activity, CatS mass and calculated CatS specific activity. RESULTS All doses of LY3000328 were well tolerated, with linear pharmacokinetics up to the 300 mg dose. The pharmacodynamic activity of LY3000328 was measured ex vivo showing a biphasic response to LY3000328, where CatS activity declines, then returns to baseline, and then increases to a level above baseline. CatS mass was also assessed post-dose which increased in a dose-dependent manner, and continued to increase after LY3000328 had been cleared from the body. CatS specific activity was additionally calculated to normalize CatS activity for changes in CatS mass. This demonstrated the increase in CatS activity was attributable to the increase in CatS mass detected in plasma. CONCLUSION A specific inhibitor of CatS which is cleared quickly from plasma may produce a transient decrease in plasma CatS activity which is followed by a more prolonged increase in plasma CatS mass which may have implications for the future clinical development of inhibitors of CatS.

Using discrete event simulation to evaluate housestaff work schedules

A discrete-event simulation model of work performed by hospital interns and residents was developed. The model incorporates such complex features as interruptions of one activity by another, involved decision processes by mobile resources, and highly variable work arrival processes. Where historical data were lacking and too expensive to collect, surveys of experts produced sufficient information to use the VISIFIT distribution fitting package to specify input processes. Validation efforts showed that the model accurately predicted the results of changes to the schedule. With its validity established, the model has since been used to investigate the ramifications of alternative systems, including the addition of a night-float team and more help from subspecialty fellows. The consequences of changes in patient load or decreased availability of senior students were also examined. The prospect for regulatory or legislative restrictions on housestaff hours make the model a valuable tool for evaluating scheduling rules and plans.<<ETX>>

Serum Lipid and Protein Changes in Healthy Dyslipidemic Subjects Given a Selective Inhibitor of p70 S6 Kinase‐1

The safety, pharmacokinetic, and pharmacodynamic effects of LY2584702, a selective inhibitor for p70 S6 serine/threonine protein kinase‐1, were evaluated in healthy dyslipidemic volunteers. LY2584702 was tolerated well as a monotherapy and dose‐dependently reduced low‐density lipoprotein cholesterol and triglycerides by up to 60% and 50%, respectively, without significantly changing high‐density lipoprotein cholesterol levels in plasma. LY2584702 also dose‐dependently decreased factor V activity. Alanine aminotransferase elevations were noted in 2 subjects when LY2584702 was given with atorvastatin. We suspect that the formation of 4‐aminopyrazolo[3,4‐d]pyrimidine (4‐APP) during metabolism may have contributed to some of the adverse effects of LY2584702, and the contribution of 4‐APP to the pharmacology merits further investigation. Although clinical investigation of LY2584702 has been terminated because of hepatotoxicity risk, we suggest that a selective inhibitor of p70 S6 serine/threonine protein kinase‐1 with a larger margin of safety and without the possibility of being metabolized to 4‐APP may be useful in the treatment of dyslipidemia.