Biomedical subjects

Jen-pei Liu

Publications and source records attributed to Jen-pei Liu.

3 recordsLinked to original sources

PubMed2002

Tests for equivalence or non-inferiority for paired binary data.

Assessment of therapeutic equivalence or non-inferiority between two medical diagnostic procedures often involves comparisons of the response rates between paired binary endpoints. The commonly used and accepted approach to assessing equivalence is by comparing the asymptotic confidence interval on the difference of two response rates with some clinical meaningful equivalence limits. This paper investigates two asymptotic test statistics, a Wald-type (sample-based) test statistic and a restricted maximum likelihood estimation (RMLE-based) test statistic, to assess equivalence or non-inferiority based on paired binary endpoints. The sample size and power functions of the two tests are derived. The actual type I error and power of the two tests are computed by enumerating the exact probabilities in the rejection region. The results show that the RMLE-based test controls type I error better than the sample-based test. To establish an equivalence between two treatments with a symmetric equivalence limit of 0.15, a minimal sample size of 120 is needed. The RMLE-based test without the continuity correction performs well at the boundary point 0. A numerical example illustrates the proposed procedures.

Biopsy↗

PubMed2002

Bridging studies in clinical development.

Global development of pharmaceutical products has become the key to the success of any pharmaceutical sponsors. It is therefore crucial to address the efficacy and safety variations of a new test pharmaceutical product among different geographic regions due to ethnic factors. Recently, geotherapeutics has attracted much attention from sponsors as well as regulatory authorities from different geographic regions. To address this issue, the International Conference on Harmonization (ICH) has published a guideline entitled "Ethnic Factors in the Acceptability of Foreign Clinical Data," which is known as ICH E5 guideline. The ICH E5 guideline provides a general framework for evaluation of the impact of ethnic factors on the efficacy, safety, dosage, and dose regimen. We provide an overview of ICH E5 guideline including ethnic sensitivity, necessity of bridging studies, types of bridging studies, and assessment of similarity between regions based on bridging evidence. In addition, challenges on the establishment of regulatory requirements, the assessment of bridging evidence, and design and analysis of bridging studies are addressed.

Algorithms↗

PubMed2002

Bayesian approach to evaluation of bridging studies.

We address the issue of analysis of clinical data generated by the bridging study conducted in the new region to evaluate the similarity for extrapolation of the foreign clinical data. A bridging study is usually conducted in the new region only after the test product is approved for commercial marketing in the original region due to its proven efficacy and safety. Sufficient information on efficacy, safety, dosage, and dose regimen has already generated in the original region. The empirical Bayesian approach is proposed to synthesize the data generated by the bridging study and foreign clinical data generated in the original region for assessment of similarity between the new and the original regions. A method for sample size determination for the bridging study is also suggested. It can be shown that the total sample size is inversely proportional to the strength of the evidence for the efficacy presented in the original region and the proportion of the patients assigned to receive the test product in the bridging study.

Algorithms↗