Sample size requirement in analytical studies for similarity assessment

ABSTRACT

For the assessment of biosimilar products, the FDA recommends a stepwise approach for obtaining the totality-of-the-evidence for assessing biosimilarity between a proposed biosimilar product and its corresponding innovative biologic product. The stepwise approach starts with analytical studies for assessing similarity in critical quality attributes (CQAs), which are relevant to clinical outcomes at various stages of the manufacturing process. For CQAs that are the most relevant to clinical outcomes, the FDA requires an equivalence test be performed for similarity assessment based on an equivalence acceptance criterion (EAC) that is obtained using a single test value of some selected reference lots. In practice, we often have extremely imbalanced numbers of reference and test lots available for the establishment of EAC. In this case, to assist the sponsors, the FDA proposed an idea for determining the number of reference lots and the number of test lots required in order not to have imbalanced sample sizes when establishing EAC for the equivalence test based on extensive simulation studies. Along this line, this article not only provides statistical justification of Dong, Tsong, and Weng’s proposal, but also proposes an alternative method for sample size requirement for the Tier 1 equivalence test.     

Morphological characteristics of external auditory canal in congenital aural stenosis patients

ObjectiveTo investigate characteristics of congenital aural stenosis (CAS) patients' external auditory canal (EAC) (position, length, orientation, etc.) and compare them with normal EAC.

Promoter hypermethylation of CDH13 is a common, early event in human esophageal adenocarcinogenesis and correlates with clinical risk factors

Although the CDH13 gene has been shown to undergo epigenetic silencing by promoter methylation in many types of tumors, hypermethylation of this gene in Barrett's-associated esophageal adenocarcinogenesis has not been studied. Two hundred fifty-nine human esophageal tissues were therefore examined for CDH13 promoter hypermethylation by real-time methylation-specific PCR. CDH13 hypermethylation showed discriminative receiver-operator characteristic curve profiles, sharply demarcating esophageal adenocarcinoma (EAC) from esophageal squamous cell carcinoma (ESCC) and normal esophagus (NE) (p < 0.0001). CDH13 normalized methylation values (NMV) were significantly higher in Barrett's esophagus (BE), dysplastic BE (D) and EAC than in NE (p < 0.0000001). CDH13 hypermethylation frequency was 0% in NE but increased early during neoplastic progression, rising to 70% in BE, 77.5% in D and 76.1% in EAC. Both CDH13 hypermethylation frequency and its mean NMV were significantly higher in BE with than without accompanying EAC. In contrast, only 5 (19.2%) of 26 ESCCs exhibited CDH13 hypermethylation. Furthermore, both CDH13 hypermethylation frequency and its mean NMV were significantly higher in EAC than in ESCC, as well as in BE or D vs. ESCC. Interestingly, mean CDH13 NMV was significantly lower in short-segment than in long-segment BE, a known clinical risk factor for neoplastic progression. Similarly, BE segment length was significantly lower in specimens with unmethylated than with methylated CDH13 promoters. 5-aza-2'-deoxycytidine treatment of OE33 EAC and KYSE220 ESCC cells reduced CDH13 methylation and increased CDH13 mRNA expression. These findings suggest that hypermethylation of CDH13 is a common, tissue-specific event in human EAC, occurs early during BE-associated neoplastic progression, and correlates with known clinical neoplastic progression risk factors.     

A p‐Menth‐1‐ene‐4,7‐diol (EC‐1) from Eucalyptus camaldulensis Dhnh. Triggers Apoptosis and Cell Cycle Changes in Ehrlich Ascites Carcinoma Cells

Anticancer activities of p‐menth‐1‐ene‐4,7‐diol (EC‐1) isolated from Eucalyptus camaldulensis Dhnh. were studied on Ehrlich ascites carcinoma (EAC) cells by MTT (3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5 diphenyl tetrazolium bromide) assay. Anticancer activities also analyzed in EAC‐bearing mice by assessment of cancer growth inhibition, changes in cancer volume, changes in life span, and hematological parameters. Apoptosis was analyzed by fluorescence microscope, DNA fragmentation assay, and flow cytometry. The expression of apoptosis‐related genes, Bcl‐2, Bcl‐X, PARP‐1, p53, and Bax, were analyzed using polymerase chain reaction (PCR). EC‐1 significantly inhibited proliferation of EAC cells in vivo and restored the altered hematological parameters of EAC‐bearing mice. Cytological observation by fluorescence microscope showed apoptosis of EAC cells upon treatment with EC‐1. Also, DNA fragmentation assay revealed EAC cells' apoptosis following EC‐1 treatment. Increased mRNA expressions of p53 and Bax genes and negative expressions of Bcl‐2 and Bcl‐X were observed in cells treated with EC‐1. These findings confirmed the induction of apoptosis by EC‐1. In addition, MTT assay showed dose‐dependent anticancer activity of EC‐1 against EAC cell. Cell cycle analysis revealed that EC‐1 treatment caused suppression of EAC cells at S phase. To conclude, EC‐1 is a novel anticancer compound and showed antiproliferative and apoptotic activities in cellular and mice models. Copyright © 2015 John Wiley & Sons, Ltd.     

Barrett Esophagus

Barrett esophagus is a metaplastic change in the lining of the distal esophageal epithelium, characterized by replacement of the normal squamous epithelium by specialized intestinal metaplasia. The presence of Barrett esophagus increases the risk of esophageal adenocarcinoma several-fold. Esophageal adenocarcinoma is a malignancy with rapidly rising incidence and persistently poor outcomes when diagnosed after the onset of symptoms. Risk factors for Barrett esophagus include chronic gastroesophageal reflux, central obesity, white race, male gender, older age, smoking, and a family history of Barrett esophagus or esophageal adenocarcinoma. Screening for Barrett esophagus in those with several risk factors followed by endoscopic surveillance to detect dysplasia or adenocarcinoma is currently recommended by society guidelines. Minimally invasive nonendoscopic tools for the early detection of Barrett esophagus are currently being developed. Multimodality endoscopic therapy—using a combination of endoscopic resection and ablation techniques—for the treatment of dysplasia and early adenocarcinoma is successful in eliminating intestinal metaplasia and preventing progression to adenocarcinoma, with outcomes comparable to those after esophagectomy. Risk stratification of those diagnosed with Barrett esophagus is a challenge at present, with active research focused on identifying clinical and biomarker panels to identify those with low and high risk of progression. This narrative review highlights some of the challenges and recent progress in this field.     

Endoscopic submucosal dissection for early Barrett’s neoplasia: a meta-analysis

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