An Approach for Widening the Bioequivalence Acceptance Limits in the Case of Highly Variable Drugs

Purpose. Highly variable drugs pose a problem in bioequivalence assessment because they often fail to meet current regulatory acceptance criteria for average bioequivalence (80–125%). This paper examines alternative approaches to establishing bioequivalence. Methods. Suggested solutions have included alternate study designs, e.g., replicate and multiple dose studies, reducing the level of the confidence interval, and widening the acceptance limits. We focus on the latter approach. Results. A rationale is presented for defining wider acceptance limits for highly variable drugs. Two previously described methods are evaluated, and a new method having more desirable properties is proposed. Conclusions. We challenge the one size fits all current definition of bioequivalence acceptance limits for highly variable drugs, proposing alternative limits or goal posts which vary in accordance with the intrasubject variability of the reference product.     

Characterisation of a myofibroblast-like cell line from an angiosarcoma

We have isolated a cell line (ASMM) by serial passage of cells from explant cultures of an angiosarcoma resected from the calf of a 62 year old female. ASMM has been in continuous culture for over eighteen months (>150 population doublings) and has a Fibroblast-like morphology with a doubling time of approximately 72 h. ASMM has a normal diploid karyology and is unable to generate tumors in nude mice or produce colonies in soft agar. Examination of the cytoskeletal proteins shows both desmin and vimentin and a low level of alpha-smooth muscle actin, which can be upregulated by treatment with TGF beta. Low levels of basal VCAM-1 are significantly upregulated with TNF alpha and reduced by the presence of TCF beta. Basal ICAM-1 is also upregulated with TNF alpha and we show an additional upregulation through TGF beta. ASMM expresses high levels of the hyaluronate receptor CD44, including the variant exons 6, 8 and 10. In addition, ASMM synthesises high levels of hyaluronate (HA), as did the original tumor. Unlike human umbilical vein endothelial cells (HUVECs) these cells were unable to generate capillary-like tubes when seeded onto basement membrane gels, and generated cords of cells containing many synthetic organelles and intermediate filaments. We were unable to detect the expression of factor VIII-related antigen, von Willebrand factor (vWF), CD31 or CD34, and were not able to induce expression of E-selectin after TNF alpha stimulation. In conclusion, this cell line represents a partially transformed population of cells which show characteristics consistent with myofibroblast-like cells. The production of high levels of HA and expression of CD44 may help to explain the high degree of agressiveness of the tumor from which ASMM was derived, as these molecules have been shown to play a role in cell motility and adhesion.     

Native Hawaiian Birth Weight and Infant Mortality: Is Birth in Hawai'i Protective?

PURPOSE OF THE PAPER: This study provides baseline information on the characteristics of Native Hawaiian mothers and the health status of their infants, comparing residents of Hawaii with those of the continental U.S. The impact of Hawaii residence on low birth weight and infant mortality among Native Hawaiians is assessed. SUMMARY OF METHODS UTILIZED: Data from the National Center for Health Statistics 1983­1987 Linked U.S. Live Birth and Infant Death file were used to examine parental characteristics, prenatal care use and infant outcomes using chi­square and logistic regression procedures. PRINCIPAL FINDINGS: Despite a higher sociodemographic risk profile among Hawaii resident mothers, preterm birth, low and very low birth weight percentages were similar. Continental infants had significantly highter percentages of very pre­term birth and macrosomia. Mortality rates in both the neonatal and post­neonatal periods, and for SIDS and perinatal causes were elevated among continental infants. Hawaii residence had a borderline protective effect on infant mortality, wehn sociodemographic and prenatal care differences were controlled. CONCLUSIONS: This study suggests a possibly protective effect of Hawaii residence on the health of Native Hawaiian infants during the period of following employer­mandated health insurance coverage but before the initiation of "gap­group" coverage and the Native Hawaiian Health Care Systems in Hawaii. RELEVANCE TO ASIAN PACIFIC ISLANDER AMERICAN POPULATIONS. This is the first report documenting the sociodemographic and health status of the growing number of Native Hawaiian mothers and their infants residing outside of Hawaii. Expanded health insurance coverage and culturally appropriate and accessible health care may contribute to improved infant health status in Hawaii. Their absence, along with possible barriers of sociocultural isolation, may account for the poorer than expected outcomes of continental infants and predict a widening gap between them and their counterparts in Hawaii. A follow­up study of the health status of Native Hawaiian mothers and infants, and their access to appropriate care in Hawaii and thei continental U.S. is recommended.     

Hypoxia and glucose metabolism in malignant tumors: evaluation by [18F]fluoromisonidazole and [18F]fluorodeoxyglucose positron emission tomography imaging.

PURPOSE: The aim of this study is to compare glucose metabolism and hypoxia in four different tumor types using positron emission tomography (PET). (18)F-labeled fluorodeoxyglucose (FDG) evaluates energy metabolism, whereas the uptake of (18)F-labeled fluoromisonidazole (FMISO) is proportional to tissue hypoxia. Although acute hypoxia results in accelerated glycolysis, cellular metabolism is slowed in chronic hypoxia, prompting us to look for discordance between FMISO and FDG uptake. EXPERIMENTAL DESIGN: Forty-nine patients (26 with head and neck cancer, 11 with soft tissue sarcoma, 7 with breast cancer, and 5 with glioblastoma multiforme) who had both FMISO and FDG PET scans as part of research protocols through February 2003 were included in this study. The maximum standardized uptake value was used to depict FDG uptake, and hypoxic volume and maximum tissue:blood ratio were used to quantify hypoxia. Pixel-by-pixel correlation of radiotracer uptake was performed on coregistered images for each corresponding tumor plane. RESULTS: Hypoxia was detected in all four patient groups. The mean correlation coefficients between FMISO and FDG uptake were 0.62 for head and neck cancer, 0.47 for breast cancer, 0.38 for glioblastoma multiforme, and 0.32 for soft tissue sarcoma. The correlation between the overall tumor maximum standardized uptake value for FDG and hypoxic volume was small (Spearman r = 0.24), with highly significant differences among the different tumor types (P < 0.005). CONCLUSIONS: Hypoxia is a general factor affecting glucose metabolism; however, some hypoxic tumors can have modest glucose metabolism, whereas some highly metabolic tumors are not hypoxic, showing discordance in tracer uptake that can be tumor type specific.     

Cell-free 59 kDa immunoreactive integrin-linked kinase: a novel marker for ovarian carcinoma.

PURPOSE: We reported that the expression of integrin-linked kinase (ILK) is up-regulated in ovarian carcinomas and that ovarian cancer cells have high expression of ILK. In this study, we have examined the expression of cell-free 59 kDa immunoreactive (ir)ILK in the serum and peritoneal fluid (PTF) of patients with ovarian cancer and evaluated its potential as a serum biomarker for early-stage screening and for monitoring clinical status of patients after chemotherapy treatment. EXPERIMENTAL DESIGN: Thirty-six serum specimens, including normal (n = 6), benign (n = 6), borderline (n = 4), grade 1 (n = 5), grade 2 (n = 5), and grade 3 (n = 10), were evaluated for the expression of irILK by Western blotting. The expression of irILK was evaluated in PTF (n = 10) and peritoneal washings from women with benign ovarian cysts (n = 4). In addition, tissue-conditioned medium obtained from the cultures of primary ovarian tumors (n = 9) was examined for the presence of irILK. Finally, the potential of serum irILK as a biomarker for ovarian cancer screening was evaluated by comparison with cancer antigen 125 (CA 125) concentrations in cancer patients before and after chemotherapy. RESULTS: irILK expression was present in normal serum and in serum of patients with benign ovarian tumors. irILK expression was 6-9-fold higher in the serum of patients with grade 1, grade 2, and grade 3 ovarian cancer than in the serum of healthy volunteers and patients with benign ovarian tumors (P < 0.01). Enhanced expression of irILK in the serum of ovarian cancer patients correlated with the concentration of CA 125. High expression of irILK was present in all 10 PTF tested. Tissue-conditioned medium prepared from malignant ovarian tumors had 4-fold more irILK expression than conditioned medium obtained from borderline and benign tumors (P < 0.01). irILK expression in serum of cancer patients was reduced to basal normal levels after six cycles of Taxol/carboplatin and was consistent with the change of CA 125 levels before and after chemotherapy. CONCLUSIONS: These data suggest that irILK is an ovarian tumor-associated antigen and implicates its potential not only as a biomarker for early-stage screening but also as a marker for monitoring the clinical condition of patients after treatment.     

Can virtual simulation of breast tangential portals accurately predict lung and heart volumes?

A treatment portal or simulator image has traditionally been used to demonstrate the lung and heart coverage of the breast tangential portal. In many cases, these images were acquired as a planning session on the linear accelerator. The patients were also CT scanned to assess the lung/heart volume and to determine the surgical site depth for the electron‐boost energy. A study using 50 consecutive patients was performed comparing the digitally reconstructed radiograph (DRR) from the virtual simulation with treatment portal images. Modification to the patient's arm position is required when performing the planning CT scans due to the aperture size of the CT scanner. Virtual simulation was used to assess the potential variation of lung and heart measurements. The average difference in lung volume between the DRR and portal image was less than 2 mm, with a range of 0?5 mm. Arm position did not have a sig­nificant impact on field deviation; however, great care was taken to minimize any changes in arm position. The modification of the arm position for CT scanning did not lead to significant variations between the DRRs and portal images. The Advantage Sim software has proven capable of producing good quality DRR images, providing a realistic representation of the lung and heart volume included in the treatment portal.     

Polilactofate microspheres for Paclitaxel delivery to central nervous system malignancies.

PURPOSE: The purpose of this study was to demonstrate that surgically implanted, controlled-release, biodegradable polilactofate microspheres (Paclimer) can be used safely to bypass the blood-brain barrier and deliver paclitaxel to malignant brain tumors. EXPERIMENTAL DESIGN: The rate of paclitaxel release from Paclimer microspheres submerged in PBS was measured in vitro by high-performance liquid chromatography. In vivo studies of Paclimer were performed as intracranial implants in Fischer 344 rats in the presence or absence of 9L gliosarcoma. Mantel-Cox statistics were used to assess the efficacy of Paclimer at extending survival of tumor-bearing animals compared with control implants. Paclimer implants tagged with [(3)H]paclitaxel were used to measure biodistribution of paclitaxel from the Paclimer implant. RESULTS: Paclimer released paclitaxel at a constant rate for up to 3 months in vitro. In vivo, Paclimer implants placed intracranially in rats released active drug for up to 30 days after implantation and doubled the median survival of rats bearing established 9L gliosarcomas (median survival of paclitaxel-treated animals = 35 days; median survival of control-treated animal = 16 days; P < 0.0001). Active drug was distributed throughout the rat brain based on liquid scintillation counting and TLC. Rats implanted with Paclimer demonstrated no overt signs of neurotoxicity and exhibited local cytopathological changes consistent with exposure to an antimicrotubule agent. CONCLUSIONS: Paclimer extends survival in a rodent model of glioma with minimal morbidity and optimal pharmacokinetics.     

Tissue-conserving surgery for prognosis,treatment, and function preservation

Objectives: To describe an approach based on initial tissue-conserving surgery used to obtain histologically determined prognostic information that has therapeutic implications and the potential to enhance preservation of function. Study Design: Analysis of a group of patients with head and neck cancer treated initially with tissue-conserving surgery based on Mohs' histographic sectioning and selected neck dissection to derive histologically determined prognostic information with therapeutic implications and preservation in function. Methods: This study is primarily based on an analysis of patients from January 1, 1989, through June 4, 1996 assigned to a protocol evaluating resection of oral cavity squamous cell cancer with margin control using Mohs' histographic technique and/or a group of patients with neck assessment of N0 on clinical examination who are undergoing supraomohyoid neck dissections. Results: Thirty-three primary tumor resections were performed using the Mohs' technique, and 54% required two or more Mohs' sections before clear histologic margins were obtained following resection based on clinically determined negative margins. There were 44 patients who underwent unilateral or bilateral supraomohyoid neck dissections, and 33% had occult, histologically positive nodes. When compared with the disease of the neck specimens, a preoperative computed tomography scan had a sensitivity of 25%, a specificity of 77%, and an accuracy of 63%. Conclusions: This report describes the effectiveness of Mohs' histographic sectioning and selective neck dissection as a means of determining prognostic information that can be used to develop a focused and cost-effective treatment program that, along with contemporary reconstructive techniques, provides a potential enhancement of function preservation. Laryngoscope, 108:1599–1604, 1998     

Detection of p21WAF1/Cip1 in brain metastases

The p21^WAF1/Cip1 (p21) protein, a negative regulator of G₁ checkpoint control, was overexpressed in the majority of human gliomas. To investigate whether p21 expression in brain metastases from various systemic origins is similar to that in gliomas and whether p21 expression is regulated differently in brain metastases and in corresponding primary tumors, we used immunohistochemical staining to examine the expression of p21 in paraffin-embedded sections prepared from primary colon and breast carcinomas and from metastatic brain tumors that originated from colon, breast, lung, and kidney cancers and from melanoma. Our results showed that 56% (28 of 50) of the brain metastases samples have more than 1% p21-positive staining cells compared with 87% of primary gliomas reported previously. Among the samples analyzed, p21 expression in brain metastases from breast carcinomas was much higher than in primary breast carcinomas. In contrast, p21 expression in brain metastases from colon carcinomas was less than primary colon carcinomas. The results from this pilot study suggest that p21 expression is regulated differently in metastatic and primary tumors.