Clinical Internship in the Surgery Department at the University of North Texas Health Science Center: Assessment of Human Antibody Response to Urokinase Part A: Specimin Acquisition Trial for the Assessment of Human Antibody Response to Urokinase in Subjects Treated for Acute Lower-Extremity Ischemia




Hughes, Telicia A.


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Significance and Specific Aim of the Study. Significance. FDA has informed Abbott Laboratories of additional concerns related to manufacturing deficiencies for urokinase (Abbokinase). Until these problems are corrected, further distribution of Abbokinase would violate federal laws designed to assure the safety of drugs for patient use. FDA’s concerns about the product relate to serious deficiencies in the manufacturing processes, the testing of the product, and the screening and testing of the donors of the kidney cells used to make Abbokinase. Abbokinase is derived from cultures of human kidney cells from newborns who have died of natural causes, and is approved in the United States to dissolve blood clots in the lungs and heart arteries. It is also approved to help clear intravenous catheters. During inspections of Abbott Laboratories and of BioWittaker, Inc. Abbott’s supplier of human kidney cells, FDA identified numerous significant deviations from current good manufacturing practice (CGMP) regulations designed to assure product safety. Compliance with CGMP is important because products manufactured from human sources have the potential to transmit infectious agents. CGMP for products such as Abbokinase requires important, overlapping safeguards in the production process, including adequate –screening of donors and testing of cells, -controls for proper harvesting, storage, and handling of materials used in all stages of manufacturing, and –processes to remove or inactivate infectious agents from the product. Over the past several months, the firm has reported to FDA that a number of in-process lots of Abbokinase was contained with microorganisms. Six such lots were found to contain various strains of reovirus, a virus that usually results in no symptoms or causes minor respiratory or gastrointestinal symptoms. Association of reovirus infection with other human diseases have been reported, although a causal link has not been established. Another in-process lot was contaminated with mycoplasma, a microorganism that can cause respiratory infections, and, on rare occasions, other infections that may be serious. Abbott has assured FDA that none of these in-process lots were manufactured into final product or distributed. These recent findings of contamination and Abbott’s inability to locate the source of the problem have raised further concerns at FDA about Abbott’s entire manufacturing process for Abbokinase. Abbot’s deviations from CGMP could significantly impact the safety of the product. One FDA concern is that deficiencies in manufacturing practices could also lead to the product being contaminated with microorganisms that have not yet been detected. FDA also obtained additional information regarding the inadequacy of the screening and testing of the mothers and donors of the human kidney cells used to produce Abbokinase. Information was also obtained regarding the seven instances of in-process lots of product being contaminated with reovirus and mycoplasma. In the letter to Abbott, the agency has detailed the steps Abbott needs to take to correct the serious and significant manufacturing deviations. These include: -completing a thorough and adequate investigation of the reovirus and mycoplasma contamination, including the source of the contamination, -manufacturing Abbokinase using human kidney cells that have been obtained, processed, and tested through adequate methods, and –assuring that fully validated methods are used in the manufacturing process to test for infectious agents and remove them. Abbott submitted a supplemental new drug application providing for changes in procurement and processing of neonatal kidney cells, improvements in the manufacture and testing of the drug substance and drug product, revised release specifications for the drug substance and drug product, revised release specifications for the drug substance and drug product, a revised CBER lot release protocol, withdrawal of the “Open-Cath” dosage strengths, and revised labeling. Labeling revisions include updated information regarding product source and adverse reactions, as well as withdrawal of the coronary artery thrombosis and catheter clearance indication. The Department of Health and Human Services completed the review of that supplemental application, as amended, and it was approved based on Abbott’s written commitments, one of which is –To conduct a study to assess the immunogenicity of Urokinase after primary dosing. Urokinase is indicated in adults for the lysis of acute massive pulmonary emboli, defined as obstruction of blood flow to a lobe or multiple segments for the lysis of pulmonary emboli accompanied by unstable hemodynamics, i.e., failure to maintain blood pressure without supportive measures. Therefore, it is important to complete this study, to meet federal requirements, so that Urokinase could be fully marketed and help to improve the quality of life. Specific Aim. 1. To access the human antibody response to Urokinase, a thrombolytic agent in subjects treated for lower extremity ischemia. A.) Technique: All subjects will receive an intra-arterial infusion of a minimum of 240,000 IU of Urokinase (UK). In part A of this study we will obtain serum specimens from subjects receiving UK. These blood specimens will be used in part B of this study for the qualitative/quantitative assessment of antibody response to Urokinase, specifically IgM, IgE, IgG. Antibody directed against the UK drug substance, API, and the inactive peptides/protein in the formulation.