Strategic, feasibility, economic, and cultural aspects of phase 0 approaches: Is it time to change the drug development process in order to increase productivity?

Research conducted over the past 2 decades has enhanced the validity and expanded the applications of microdosing and other phase 0 approaches in drug development. Phase 0 approaches can accelerate drug development timelines and reduce attrition in clinical development by increasing the quality of candidates entering clinical development and by reducing the time to "go-no-go" decisions. This can be done by adding clinical trial data (both healthy volunteers and patients) to preclinical candidate selection, and by applying methodological and operational advantages that phase 0 have over traditional approaches. The main feature of phase 0 approaches is the limited, subtherapeutic exposure to the test article. This means a reduced risk to research volunteers, and reduced regulatory requirements, timelines, and costs of first-in-human (FIH) testing. Whereas many operational aspects of phase 0 approaches are similar to those of other early phase clinical development programs, they have some unique strategic, regulatory, ethical, feasibility, economic, and cultural aspects. Here, we provide a guidance to these operational aspects and include case studies to highlight their potential impact in a range of clinical development scenarios.

Phase 0/microdosing approaches: time for mainstream application in drug development?

Phase 0 approaches - which include microdosing - evaluate subtherapeutic exposures of new drugs in first-in-human studies known as exploratory clinical trials. Recent progress extends phase 0 benefits beyond assessment of pharmacokinetics to include understanding of mechanism of action and pharmacodynamics. Phase 0 approaches have the potential to improve preclinical candidate selection and enable safer, cheaper, quicker and more informed developmental decisions. Here, we discuss phase 0 methods and applications, highlight their advantages over traditional strategies and address concerns related to extrapolation and developmental timelines. Although challenges remain, we propose that phase 0 approaches be at least considered for application in most drug development scenarios.

Phase 0, including microdosing approaches: Applying the Three Rs and increasing the efficiency of human drug development.

Phase 0 approaches, including microdosing, involve the use of sub-therapeutic exposures to the tested drugs, thus enabling safer, more-relevant, quicker and cheaper first-in-human (FIH) testing. These approaches also have considerable potential to limit the use of animals in human drug development. Recent years have witnessed progress in applications, methodology, operations, and drug development culture. Advances in applications saw an expansion in therapeutic areas, developmental scenarios and scientific objectives, in, for example, protein drug development and paediatric drug development. In the operational area, the increased sensitivity of Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS), expansion of the utility of Positron Emission Tomography (PET) imaging, and the introduction of Cavity Ring-Down Spectroscopy (CRDS), have led to the increased accessibility and utility of Phase 0 approaches, while reducing costs and exposure to radioactivity. PET has extended the application of microdosing, from its use as a predominant tool to record pharmacokinetics, to a method for recording target expression and target engagement, as well as cellular and tissue responses. Advances in methodology include adaptive Phase 0/Phase 1 designs, cassette and cocktail microdosing, and Intra-Target Microdosing (ITM), as well as novel modelling opportunities and simulations. Importantly, these methodologies increase the predictive power of extrapolation from microdose to therapeutic level exposures. However, possibly the most challenging domain in which progress has been made, is the culture of drug development. One of the main potential values of Phase 0 approaches is the opportunity to terminate development early, thus not only applying the principle of 'kill-early-kill-cheap' to enhance the efficiency of drug development, but also obviating the need for the full package of animal testing required for therapeutic level Phase 1 studies. Finally, we list developmental scenarios that utilised Phase 0 approaches in novel drug development.

Integrating Pharmacoproteomics into Early-Phase Clinical Development: State-of-the-Art, Challenges, and Recommendations.

Pharmacoproteomics is the study of disease-modifying and toxicity parameters associated with therapeutic drug administration, using analysis of quantitative and temporal changes to specific, predetermined, and select proteins, or to the proteome as a whole. Pharmacoproteomics is a rapidly evolving field, with progress in analytic technologies enabling processing of complex interactions of large number of unique proteins and effective use in clinical trials. Nevertheless, our analysis of clinicaltrials.gov and PubMed shows that the application of proteomics in early-phase clinical development is minimal and limited to few therapeutic areas, with oncology predominating. We review the history, technologies, current usage, challenges, and potential for future use, and conclude with recommendations for integration of pharmacoproteomic in early-phase drug development.

Phase-0/microdosing studies using PET, AMS, and LC-MS/MS: a range of study methodologies and conduct considerations. Accelerating development of novel pharmaceuticals through safe testing in humans - a practical guide.

INTRODUCTION: Phase-0 studies, including microdosing, also called Exploratory Investigational New Drug (eIND) or exploratory clinical trials, are a regulatory framework for first-in-human (FIH) trials. Common to these approaches is the use and implied safety of limited exposures to test articles. Use of sub-pharmacological doses in phase-0/microdose studies requires sensitive analytic tools such as accelerator mass spectrometer (AMS), Positron Emission Tomography (PET), and Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) to determine drug disposition. Areas covered: Here we present a practical guide to the range of methodologies, design options, and conduct strategies that can be used to increase the efficiency of drug development. We provide detailed examples of relevant developmental scenarios. Expert opinion: Validation studies over the past decade demonstrated the reliability of extrapolation of sub-pharmacological to therapeutic-level exposures in more than 80% of cases, an improvement over traditional allometric approaches. Applications of phase-0/microdosing approaches include study of pharmacokinetic and pharmacodynamic properties, target tissue localization, drug-drug interactions, effects in vulnerable populations (e.g. pediatric), and intra-target microdosing (ITM). Study design should take into account the advantages and disadvantages of each analytic tool. Utilization of combinations of these analytic techniques increases the versatility of study designs and the power of data obtained.

Knowledge and Perception about Clinical Research Shapes Behavior: Face to Face Survey in Korean General Public.

Considering general public as potential patients, identifying factors that hinder public participation poses great importance, especially in a research environment where demands for clinical trial participants outpace the supply. Hence, the aim of this study was to evaluate knowledge and perception about clinical research in general public. A total of 400 Seoul residents with no previous experience of clinical trial participation were selected, as representative of population in Seoul in terms of age and sex. To minimize selection bias, every fifth passer-by was invited to interview, and if in a cluster, person on the very right side was asked. To ensure the uniform use of survey, written instructions have been added to the questionnaire. Followed by pilot test in 40 subjects, the survey was administered face-to-face in December 2014. To investigate how perception shapes behavior, we compared perception scores in those who expressed willingness to participate and those who did not. Remarkably higher percentage of responders stated that they have heard of clinical research, and knew someone who participated (both, P < 0.001) compared to India. Yet, the percentage of responders expressed willingness to participate was 39.3%, a significantly lower rate than the result of the India (58.9% vs. 39.3%, P < 0.001). Treatment benefit was the single most influential reason for participation, followed by financial gain. Concern about safety was the main reason for refusal, succeeded by fear and lack of trust. Public awareness and educational programs addressing these negative perceptions and lack of knowledge will be effective in enhancing public engaged in clinical research.

Antidepressant Regulatory Warnings, Prescription Patterns, Suicidality and Other Aggressive Behaviors in Major Depressive Disorder and Anxiety Disorders.

In 2004 the Food and Drug Administration issued a warning on the risk of suicidality in children and adolescents receiving antidepressants. This was followed by reports of changes in antidepressant prescription patterns, suicidality and other aggressive behaviors, but debate is continuing regarding the nature and magnitude of these changes. We examined a large physician database for impact of the warning on antidepressant prescriptions, suicidality and other aggressive behaviors in major depressive disorder (MDD) and anxiety disorders in adult and pediatric patients. We analyzed electronic database covering over 100,000 patients, treated in Pre- (before 2003) and Post- (after 2004) warning periods. We compared strength of the association between the measures and the time period with two tests. Multivariate logistic regression analyses were performed to ascertain the unique effect of each parameter. Of 10,089 MDD (61.0 %) and anxiety disorders (39.0 %) patients, 65.2 % received antidepressant prescription and 16.1 % were pediatric patients. In post-warning period, there was a greater reduction in adult versus pediatric antidepressant prescription rates. Logistic modeling showed greater likelihood of antidepressant prescription in MDD as compared with anxiety disorders in post-warning period. Pediatric patients were more likely than adults to receive fluoxetine during the post-warning period. There was an overall reduction in suicidality and other aggressive behaviors in the post-warning period. Regulatory warnings may have had an impact on antidepressant benefit/risk assessment and consequent utilization, therapeutic effects, and adverse events. Our observations suggest that psychiatrists may heed regulatory warnings, but may also exert professional independence and discrimination in their application.

Thyroid Autoimmune Antibodies and Major Depressive Disorder in Women.

INTRODUCTION: Anti-thyroid antibodies are associated with extra-thyroid diseases such as Graves' ophthalmopathy and Hashimoto's encephalopathy. Some evidence suggests that anti-thyroid antibodies are also associated with depression. Interleukin (IL)-17 appears to play an important role in autoimmune thyroid disease. This study investigated whether specific thyroid autoantibodies and IL-17 distinguished persons with depression from non-depressed controls. MATERIALS AND METHODS: Forty-seven adult females with non-psychotic, current major depressive disorder and 80 healthy female controls participated in this study. Thyroid peroxidase antibodies, thyroglobulin antibodies, thyroid-stimulating hormone (TSH) receptor antibodies, free T3 and T4, TSH and IL-17 were measured from the serum. Measurements were repeated to assess test-retest reliability. Receiver operating characteristic (ROC) curves were used to estimate discriminatory values of the measurements. Differences between groups and associations between the clinical and biochemical assessments were analysed. RESULTS: Median TSH receptor antibody concentration was significantly higher in the depressed than control group (P <0.001). Area under the ROC curve was 0.80 (95% CI, 0.73 to 0.88). Higher TSH receptor antibody titres were associated with greater depression severity scores (r = 0.33, P <0.05). IL-17 levels were not associated with TSH receptor antibody levels or depression severity scores. Thyroid function and other thyroid autoantibodies were not associated with depression severity. CONCLUSION: TSH receptor antibodies might be a biomarker of immune dysfunction in depression.

Intraarterial Microdosing: A Novel Drug Development Approach, Proof-of-Concept PET Study in Rats.

UNLABELLED: Intraarterial microdosing (IAM) is a novel drug development approach combining intraarterial drug delivery and microdosing. We aimed to demonstrate that IAM leads to target exposure similar to that of systemic full-dose administration but with minimal systemic exposure. IAM could enable the safe, inexpensive, and early study of novel drugs at the first-in-human stage and the study of established drugs in vulnerable populations. METHODS: Insulin was administered intraarterially (ipsilateral femoral artery) or systemically to 8 CD IGS rats just before blood sampling or 60-min (18)F-FDG uptake PET imaging of ipsilateral and contralateral leg muscles (lateral gastrocnemius) and systemic muscles (spinotrapezius). The (18)F-FDG uptake slope analysis was used to compare the interventions. Plasma levels of insulin and glucose were compared using area under the curve calculated by the linear trapezoidal method. A physiologically based computational pharmacokinetics/pharmacodynamics model was constructed to simulate the relationship between the administered dose and response over time. RESULTS: (18)F-FDG slope analysis found no difference between IAM and systemic full-dose slopes (0.0066 and 0.0061, respectively; 95% confidence interval [CI], -0.024 to 0.029; P = 0.7895), but IAM slope was statistically significantly greater than systemic microdose (0.0018; 95% CI, -0.045 to -0.007; P = 0.0147) and sham intervention (-0.0015; 95% CI, 0.023-0.058; P = 0.0052). The pharmacokinetics/pharmacodynamics data were used to identify model parameters that describe membrane insulin binding and glucose-insulin dynamics. CONCLUSION: Target exposure after IAM was similar to systemic full dose administration but with minimal systemic effects. The computational pharmacokinetics/pharmacodynamics model can be generalized to predict whole-body response. Findings should be validated in larger, controlled studies in animals and humans using a range of targets and classes of drugs.

Clinical Research Environment in India: Challenges and Proposed Solutions.

India has compelling need and keen aspirations for indigenous clinical research. Notwithstanding this need and previously reported growth the expected expansion of Indian clinical research has not materialized. We reviewed the scientific literature, lay press reports, and ClinicalTrials.gov data for information and commentary on projections, progress, and impediments associated with clinical trials in India. We also propose targeted solutions to identified challenges. The Indian clinical trial sector grew by (+) 20.3% CAGR (compound annual growth rate) between 2005 and 2010 and contracted by (-) 14.6% CAGR between 2010 and 2013. Phase-1 trials grew by (+) 43.5% CAGR from 2005-2013, phase-2 trials grew by (+) 19.8% CAGR from 2005-2009 and contracted by (-) 12.6% CAGR from 2009-2013, and phase-3 trials grew by (+) 13.0% CAGR from 2005-2010 and contracted by (-) 28.8% CAGR from 2010-2013. This was associated with a slowing of the regulatory approval process, increased media coverage and activist engagement, and accelerated development of regulatory guidelines and recuperative initiatives. We propose the following as potential targets for restorative interventions: Regulatory overhaul (leadership and enforcement of regulations, resolution of ambiguity in regulations, staffing, training, guidelines, and ethical principles [e.g., compensation]).Education and training of research professionals, clinicians, and regulators.Public awareness and empowerment. After a peak in 2009-2010, the clinical research sector in India appears to be experiencing a contraction. There are indications of challenges in regulatory enforcement of guidelines; training of clinical research professionals; and awareness, participation, partnership, and the general image amongst the non-professional media and public. Preventative and corrective principles and interventions are outlined with the goal of realizing the clinical research potential in India.

Ethics Standards (HRPP) and Public Partnership (PARTAKE) to Address Clinical Research Concerns in India: Moving Toward Ethical, Responsible, Culturally Sensitive, and Community-Engaging Clinical Research.

Like other emerging economies, India's quest for independent, evidence-based, and affordable healthcare has led to robust and promising growth in the clinical research sector, with a compound annual growth rate (CAGR) of 20.4% between 2005 and 2010. However, while the fundamental drivers and strengths are still strong, the past few years witnessed a declining trend (CAGR -16.7%) amid regulatory concerns, activist protests, and sponsor departure. And although India accounts for 17.5% of the world's population, it currently conducts only 1% of clinical trials. Indian and international experts and public stakeholders gathered for a 2-day conference in June 2013 in New Delhi to discuss the challenges facing clinical research in India and to explore solutions. The main themes discussed were ethical standards, regulatory oversight, and partnerships with public stakeholders. The meeting was a collaboration of AAHRPP (Association for the Accreditation of Human Research Protection Programs)-aimed at establishing responsible and ethical clinical research standards-and PARTAKE (Public Awareness of Research for Therapeutic Advancements through Knowledge and Empowerment)-aimed at informing and engaging the public in clinical research. The present article covers recent clinical research developments in India as well as associated expectations, challenges, and suggestions for future directions. AAHRPP and PARTAKE provide etiologically based solutions to protect, inform, and engage the public and medical research sponsors.

Pharmacogenomics in early-phase clinical development.

Pharmacogenomics (PGx) offers the promise of utilizing genetic fingerprints to predict individual responses to drugs in terms of safety, efficacy and pharmacokinetics. Early-phase clinical trial PGx applications can identify human genome variations that are meaningful to study design, selection of participants, allocation of resources and clinical research ethics. Results can inform later-phase study design and pipeline developmental decisions. Nevertheless, our review of the clinicaltrials.gov database demonstrates that PGx is rarely used by drug developers. Of the total 323 trials that included PGx as an outcome, 80% have been conducted by academic institutions after initial regulatory approval. Barriers for the application of PGx are discussed. We propose a framework for the role of PGx in early-phase drug development and recommend PGx be universally considered in study design, result interpretation and hypothesis generation for later-phase studies, but PGx results from underpowered studies should not be used by themselves to terminate drug-development programs.

PARTAKE survey of public knowledge and perceptions of clinical research in India.

BACKGROUND: A public that is an informed partner in clinical research is important for ethical, methodological, and operational reasons. There are indications that the public is unaware or misinformed, and not sufficiently engaged in clinical research but studies on the topic are lacking. PARTAKE - Public Awareness of Research for Therapeutic Advancements through Knowledge and Empowerment is a program aimed at increasing public awareness and partnership in clinical research. The PARTAKE Survey is a component of the program. OBJECTIVE: To study public knowledge and perceptions of clinical research. METHODS: A 40-item questionnaire combining multiple-choice and open-ended questions was administered to 175 English- or Hindi-speaking individuals in 8 public locations representing various socioeconomic strata in New Delhi, India. RESULTS: Interviewees were 18-84 old (mean: 39.6, SD ± 16.6), 23.6% female, 68.6% employed, 7.3% illiterate, 26.3% had heard of research, 2.9% had participated and 58.9% expressed willingness to participate in clinical research. The following perceptions were reported (% true/% false/% not aware): 'research benefits society' (94.1%/3.5%/2.3%), 'the government protects against unethical clinical research' (56.7%/26.3%/16.9%), 'research hospitals provide better care' (67.2%/8.7%/23.9%), 'confidentiality is adequately protected' (54.1%/12.3%/33.5%), 'participation in research is voluntary' (85.3%/5.8%/8.7%); 'participants treated like 'guinea pigs'' (20.7%/53.2%/26.0%), and 'compensation for participation is adequate' (24.7%/12.9%/62.3%). CONCLUSIONS: Results suggest the Indian public is aware of some key features of clinical research (e.g., purpose, value, voluntary nature of participation), and supports clinical research in general but is unaware of other key features (e.g., compensation, confidentiality, protection of human participants) and exhibits some distrust in the conduct and reporting of clinical trials. Larger, cross-cultural surveys are required to inform educational programs addressing these issues.

Microdosing and drug development: past, present and future.

INTRODUCTION: Microdosing is an approach to early drug development where exploratory pharmacokinetic data are acquired in humans using inherently safe sub-pharmacologic doses of drug. The first publication of microdose data was 10 years ago and this review comprehensively explores the microdose concept from conception, over the past decade, up until the current date. AREAS COVERED: The authors define and distinguish the concept of microdosing from similar approaches. The authors review the ability of microdosing to provide exploratory pharmacokinetics (concentration-time data) but exclude microdosing using positron emission tomography. The article provides a comprehensive review of data within the peer-reviewed literature as well as the latest applications and a look into the future, towards where microdosing may be headed. EXPERT OPINION: Evidence so far suggests that microdosing may be a better predictive tool of human pharmacokinetics than alternative methods and combination with physiologically based modelling may lead to much more reliable predictions in the future. The concept has also been applied to drug-drug interactions, polymorphism and assessing drug concentrations over time at its site of action. Microdosing may yet have more to offer in unanticipated directions and provide benefits that have not been fully realised to date.

Research Question, Study Design and Continuous Research Education and Training Exercises (CREATE) Program.

The clinical research project starts with identifying the optimal research question, one that is ethical, impactful, feasible, scientifically sound, novel, relevant, and interesting. The project continues with the design of the study to answer the research question. Such design should be consistent with ethical and methodological principles, and make optimal use of resources in order to have the best chances of identifying a meaningful answer to the research question. Physicians and other healthcare providers are optimally positioned to identify meaningful research questions the answer to which could make significant impact on healthcare delivery. The typical medical education curriculum, however, lacks solid training in clinical research. We propose CREATE (Continuous Research Education And Training Exercises) as a peer- and group-based, interactive, analytical, customized, and accrediting program with didactic, training, mentoring, administrative, and professional support to enhance clinical research knowledge and skills among healthcare professionals, promote the generation of original research projects, increase the chances of their successful completion and potential for meaningful impact. The key features of the program are successive intra- and inter-group discussions and confrontational thematic challenges among participating peers aimed at capitalizing on the groups' collective knowledge, experience and skills, and combined intellectual processing capabilities to optimize choice of research project elements and stakeholder decision-making.

Comparison of duloxetine, escitalopram, and sertraline effects on cytochrome P450 2D6 function in healthy volunteers.

This study is the first to directly compare the relative effects of duloxetine, escitalopram, and sertraline on the functional activity of the drug-metabolizing cytochrome P450 2D6 enzyme as assessed by changes in the pharmacokinetics of the cytochrome P450 2D6 model substrate drug, metoprolol. Single-dose pharmacokinetics of metoprolol were measured before and after 17 days of treatment with escitalopram 20 mg/d, duloxetine 60 mg/d, or sertraline 100 mg/d in young healthy male and female participants. The outcome measures were changes in metoprolol peak plasma levels, area under the plasma concentration-time curve, and clearance. The results were tested using paired t tests and independent t tests. The addition of each drug produced statistically significant changes in metoprolol pharmacokinetics. The rank order for the change in metoprolol area under the plasma concentration-time curve was duloxetine (180%) > escitalopram (89%) > sertraline (48% and 67%). Compared with sertraline, duloxetine produced statistically significantly larger changes in metoprolol pharmacokinetic parameters. The changes produced by escitalopram and sertraline were not statistically different.

A placebo-controlled, randomized withdrawal study of sertraline for major depressive disorder in Japan.

The objective of this double-blind, placebo-controlled, multicentre randomized withdrawal study was to evaluate the efficacy and tolerability of sertraline for 16 weeks in treating Japanese patients with major depressive disorder (MDD) who had achieved a response to 8 weeks of sertraline treatment. Patients (n=361) were initially treated with 8 weeks of open-label sertraline treatment followed by 16 weeks of double-blind treatment with either sertraline (50-100 mg/day) or placebo. Responders during the open-label phase were eligible to be entered into the double-blind phase. A total of 235 patients (65.1%) were entered to the double-blind phase and randomly assigned to receive sertraline (n=117) or placebo (n=118). A significantly (P=0.016) lower relapse rate was found for sertraline (8.5%) compared to placebo (19.5%) during the double-blind phase. Examination of time-to-relapse showed that the relapse free rate curve was significantly higher for sertraline (log-rank test, P=0.026) than placebo. Mean changes from beginning to end of the double-blind phase on measure of depressive symptoms, quality of life and global improvement also significantly favoured sertraline over placebo. Sertraline was well-tolerated, with similar adverse events as found in previous studies. These results confirm the efficacy of sertraline in preventing the relapse of MDD in Japanese patients.

Randomized trial of sertraline versus venlafaxine XR in major depression: efficacy and discontinuation symptoms.

BACKGROUND: The comparative efficacy of selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) was recently debated. Meta-analyses, based mainly on fluoxetine comparator data, suggest that the SNRI venlafaxine has superior efficacy to SSRIs in treatment of major depression. OBJECTIVE: To compare quality of life (QOL), efficacy, safety, and tolerability associated with sertraline and venlafaxine extended release (XR) for treatment of DSM-IV major depression. METHOD: This was an 8-week, double-blind, randomized study of sertraline (50-150 mg/day) versus venlafaxine XR (75-225 mg/day), followed by a 2-week taper period. Subjects were recruited from 7 sites in Turkey and 6 sites in Australia between October 2002 and July 2003. The primary outcome measure was the Quality of Life Enjoyment and Satisfaction Questionnaire. Secondary outcome measures included measures of depression (including response and remission), anxiety, pain, safety (e.g., blood pressure), and tolerability (e.g., discontinuation symptoms). RESULTS: A total of 163 subjects received study treatment (women, 69%; mean age, 37.0 [SD = 12.9] years). No significant differences in QOL or efficacy were noted between treatments on the primary or secondary endpoints for the total study population or the anxious depression and severe depression subgroups. A priori analyses of symptoms associated with treatment discontinuation demonstrated no difference between treatment groups. However, in post hoc analyses, sertraline was associated with less burden of moderate to severe discontinuation symptoms. Venlafaxine XR was associated with a relative increase in mean blood pressure (supine diastolic blood pressure, -4.4 mm Hg difference at week 8/last observation carried forward). CONCLUSION: Sertraline and venlafaxine XR demonstrated comparable effects on QOL and efficacy in treatment of major depression, although sertraline may be associated with a lower symptom burden during treatment discontinuation and a reduced risk of blood pressure increase.

A placebo-controlled, randomized withdrawal study of sertraline for panic disorder in Japan.

The objective of this double-blind, placebo-controlled randomized withdrawal study was to evaluate the efficacy and safety of sertraline for 8 weeks in treating Japanese patients with DSM-IV panic disorder. Patients (n=394) were initially treated with 8 weeks of open-label sertraline followed by 8 weeks of double-blind treatment with either sertraline (50-100 mg/day) or placebo. Responders during the open-label phase were eligible to be entered into the double-blind phase. Two hundred and forty patients were entered to the double-blind phase and randomly assigned to receive sertraline (n=119) or placebo (n=121). On the primary efficacy measure (relapse), there was no significant difference between the two treatment groups (sertraline 10.1%; placebo 13.2%). However, the frequency of panic attacks was significantly (P=0.012) lower for sertraline compared to placebo. The proportion of sertraline-treated patients who met response criteria (Clinical Global Impression-Improvement Scale score of 1 or 2) at the end of double-blind phase treatment was also significantly (P=0.003) higher for sertraline (89.9%) compared to placebo (74.4%). Panic Disorder Severity Scale total score was significantly (P=0.012) lower in the sertraline group compared to the placebo group. Adverse events during acute treatment were consistent with the known adverse event profile of sertraline, and the incidence of adverse events during the double-blind phase treatment was not different between sertraline and placebo.

Optimal length of antidepressant trials in late-life depression.

There is a long-standing belief that elderly patients take longer to respond to antidepressant treatment than younger patients, and thus, require longer trials to respond or remit. This has led to the question: What is the minimum duration of antidepressant treatment necessary to identify responders in older depressed adults? A 12-week duration was tested based on 2 separate ideas: (1) older patients take longer to respond and, therefore, require longer trials to achieve optimal response (ie, remission), and (2) patients who are still quite symptomatic at Week 11 may improve dramatically and meet response, or even remission, criteria by Week 12. The data that support these beliefs are sparse and what little exist are contradictory. Rates of response and time-to-response were analyzed in depressed older adults in two 12-week clinical trials. The results do not support the belief that older patients take longer to respond or that, generally, as a group, older patients have a lower response rate. Furthermore, if patients do not have > or =30% reduction in baseline Hamilton Rating Score for Depression (HRSD) by Week 4, the probability that they will meet remission criteria (defined as HRSD < or =10 and HRSD < or =6) at the end of the trial is only 35% and 16.5%, respectively. Therefore, a 12-week trial is not necessary for all older patients; rather, the degree of improvement in the first 4 to 6 weeks identifies patients who are highly likely to benefit from continuing antidepressant treatment as well as those who very probably should have their treatment regimen altered at that point.