• Journal of the Korean Data and Information Science Society
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• v.22 no.3
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• pp.605-612
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• 2011

In multi-center randomized clinical trial the treatment eect may be changed over centers. It is thus important to investigate the heterogeneity in treatment eect between centers. For this, uncorrelated random-eect models assuming independence between random-eect terms have been often used, which may be a strong assumption. In this paper we propose a correlated frailty modelling approach of investigating such heterogeneity using the hierarchical-likelihood method when the outcome is time-to-event. In particular, we show how to construct a proper prediction interval for frailty, which explores graphically the potential heterogeneity for a treatment-by-center interaction term. The proposed method is illustrated via numerical studies based on data from the design of a multi-center clinical trial.

• Communications for Statistical Applications and Methods
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• v.5 no.3
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• pp.707-722
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• 1998

This paper evaluates a new clinical trial designs for low infection rate disease. This type of sparse disease reaction makes the traditional two sample t-test or Wilcoxon rank-sum test inefficient compared to a new test suggested. The new test, which is based solely on the larger changes, is shown to be more effective than existing method by simulation for small samples. However, this test can be shown to be connected to the locally most powerful rank test under certain practical conditions. This design is motivated in testing the treatment effects in periodontal disease research.

• Journal of Korean Medicine for Obesity Research
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• v.12 no.1
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• pp.48-58
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• 2012

Objectives These prescribing recommendations have been written to guide clinicians on the appropriate use of Bangpungtongseong-san(BT) and Bangkihwangki-tang(BH) in the treatment of obesity. These recommendation are aimed at providing evidence based information concerning diagnosis and management of obesity. Methods We collected all relevant references about treatment effect of BT and BH on obesity in the forms of meta-analysis, systematic review, randomized controlled trial, case-control study, observational study and practice guideline from international and domestic databases and paper journals. We examined treatment effect, side effects, recommendations for dose, indication and contraindication of BT and BH. Results The treatment effect of BT and BH on obesity has been proved through clinical trial. BT is indicated for obese patients (Body mass index, $BMI{\geq}25$) with strong abdomen and a tendency to constipation, BH is indicated for obese patients ($BMI{\geq}25$) with a fair skinned, soft muscled, edematous and sweat easily. Conclusion We wish the information contained in theses recommendations will help clinicians reach a reasonable and beneficial decision with evidence-based results. Further studies are strongly needed to develop better treatment strategies for herbal medicines on obesity.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.10 no.1
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• pp.83-96
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• 2024

Peptide-based radiopharmaceuticals have brought significant advancements in the diagnosis and treatment of various cancers, serving as a powerful tool in nuclear medicine. These radiopharmaceuticals utilize the high specificity of peptides for certain cell receptors, such as the prostate-specific membrane antigen in prostate cancer and somatostatin receptors in neuroendocrine tumors. This review paper aims to describe the clinical benefits of peptide-based radiopharmaceuticals, emphasizing their high target affinity, improved imaging quality, and therapeutic efficacy. By integrating ongoing research and clinical trial data, the innovative impact of peptide-based radiopharmaceuticals in nuclear medicine is highlighted.

• The Korean Journal of Applied Statistics
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• v.37 no.4
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• pp.411-444
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• 2024

The objective of Phase I clinical trials is to ascertain the maximum tolerated dose (MTD) that is safe for human administration. Accurately determining the MTD within an acceptable safety margin is imperative, necessitating evaluations up to sufficiently high doses. To estimate the MTD, a plethora of methods have been developed, encompassing algorithm-based, model-based, and model-assisted techniques. In this paper, a new dose exploration method based on continual reassessment method (CRM) is proposed to address for the shortcomings of existing dose exploration methods. Through a comprehensive simulation study, this method's efficacy was compared against that of existing methodologies across a variety of scenarios. The findings from this study underscore its enhanced precision and safety in estimating the MTD, alongside a reduction in the number of subjects required for testing.

• The Journal of Korean Obstetrics and Gynecology
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• v.24 no.3
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• pp.171-189
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• 2011

Objectives: Female Sexual Dysfuction(FSD) is a common gynecologic condition and its prevalence is more higher than men. Despite its high prevalence and clinical importance, research on FSD is not enough in both of oriental and western medicine. The purpose of this study is to review research tendency of recent oriental medicine studies on FSD and to suggest the following research on FSD. Methods: We searched oriental medicine papers related to FSD published in the last 10 years(2001-2011) through Korean Medicine Gynecology Society database, KISS, RISS, NDSL, CNKI(China National Knowledge Infrastructure), and Pubmed. Results: 26 papers were searched, then 18 papers of them were related to Traditional Chinese Medicine(TCM), 8 papers of them were related to Korean Medicine(KM). In classification according to paper type, 16 papers were clinical study, 1 paper was experimental study, 2 papers were bibliographic study, and 7 papers were the other study. Then 5 papers of clinical study was Randomized Controlled Trial(RCT). Conclusion: There was a lack of oriental medicine research on FSD. On the base of this study, so further research is needed. Especially, Clinical trials such as RCT have strong objective evidence power in the viewpoint of Evidence Based Medicine(EBM) are needed.

• Communications for Statistical Applications and Methods
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• v.18 no.5
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• pp.581-594
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• 2011

The traditional method of 3+3 standard design and model-based Bayesian continual reassessment method (CRM) are commonly used in Phase I clinical trials to identify the maximal tolerated dose(MTD) of a new drug. In this paper we review clinical examples of Phase I trials that were carried out in patients with refractory or relapsed leukemia and myelodysplastic syndrome. The recently proposed 3+1+1 design and rolling-6 design can shorten the trial duration, when a very slow accrual of patients with a simple 3+3 standard design may result in the untimely termination of trials. Too conservative approaches in determining the dose levels in Phase I clinical trials can leave clinical investigators unable to accurately determine the MTD. When determining future patient doses, the designs that use a time-to-event CRM can cooperate late toxicities by accounting for the proportion of the observation period of each enrolled patient. With the CRM design, simulations under different scenarios during the trial are important in detecting the under- or over-estimation of the initial estimate of the dose-limiting toxicity rate for each dose level. We present the advantages and drawbacks of the designs used in Phase I clinical trials for leukemia patients.

• Communications for Statistical Applications and Methods
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• v.22 no.4
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• pp.389-399
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• 2015

It is important not to overcalculate sample sizes for clinical trials due to economic, ethical, and scientific reasons. Kang and Kim (2014) investigated the accuracy of a well-known sample size calculation formula based on the approximate power for continuous endpoints in equivalence trials, which has been widely used for Development of Biosimilar Products. They concluded that this formula is overly conservative and that sample size should be calculated based on an exact power. This paper extends these results to binary endpoints for three popular metrics: the risk difference, the log of the relative risk, and the log of the odds ratio. We conclude that the sample size formulae based on the approximate power for binary endpoints in equivalence trials are overly conservative. In many cases, sample sizes to achieve 80% power based on approximate powers have 90% exact power. We propose that sample size should be computed numerically based on the exact power.

• Communications for Statistical Applications and Methods
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• v.15 no.5
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• pp.727-735
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• 2008

Consider a clinical trial in which the main end-point is survival. Suppose after the start of the study an intermediate event occurs which may be influenced by a covariate(or treatment). In many clinical studies the occurrence of an intermediate event may change the survival distribution. This investigation develops two-stage model which, in the first stage, models the effect of covariate on the intermediate event and models the relationship between survival time and covariate as well as the intermediate event. In this paper, the two-stage model is presented in order to model intermediate event and a test based on this model is also provided. A numerical simulations are carried out to evaluate its overall significance level.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3284-3288
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• 2013

This paper describes first development and validation of pentafluorophenylprophyl ligand-based liquid chromatography coupled to tandem mass spectrometry (PFPLC-MS/MS) method to determine metformin, a highly polar compound, in human plasma. Metformin and Phenformin (internal standard) were extracted from human plasma 50 ${\mu}L$ with a single-step protein precipitation. The chromatographic separation was performed using a linear gradient elution of mobile phase involving 5.0 mM ammonium formate solution with 0.1% formic acid (A) and acetonitrile (B) over 3.0 min of run time on a Phenomenex Luna PFP column. The detection was performed using a triple-quadrupole tandem mass spectrometer (Waters Quattro micro) with electrospray ionization in the mode of positive ionization and multiple-reaction monitoring (MRM). The developed method was validated with 5.0 ng/mL of lower limit of quantification (LLOQ). The calibration curve was linear over 5-3000 ng/mL of the concentration range ($R^2$ > 0.99). The specificity, selectivity, carry-over effect, precision, accuracy and stability of the method met the acceptance criteria. The method developed in this study had had rapidness, simplicity and ruggedness. The reliable method was successfully applied to high throughput analysis of real samples for a practical purpose of a pharmacokinetic study.