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1-Protease Inhibitors for Treatment of 1-Antitrypsin Deficiency
Senior Vice President Research and Development Talecris Biotherapeutics 79 TW Alexander Drive, 4101 Building Research Triangle Park, North Carolina 27709 fax 919/316-6675 steve.petteway{at}talecris.com
Published Online, January 31, 2006. www.theannals.com, DOI 10.1345/aph.1E061b
1-antitrypsin (AAT) deficiency and compared 2 of the 3 human
plasma-derived AAT products for augmentation therapy, Aralast
1 proteinase inhibitor (human), introduced in 2003 and
Prolastin 1 proteinase inhibitor (human), available since
1988. I wish to bring to your attention some major misinterpretations of the
available data relating to Prolastin that are contained within this paper. The authors discussed the respective purification procedures for Aralast and Prolastin from human plasma, in particular the processes employed to reduce the risk of transmission of viral agents. The manufacturing procedure for Aralast is described in some detail and is stated to include 2 virus inactivation steps (treatment with a solvent detergent and nanofiltration). This statement is inaccurate: nanofiltration is a virus removal step and not a virus inactivation step. Reference to the Aralast package insert shows that there are, in effect, 2 virus removal steps (alcohol fractionation and nanofiltration) and one inactivation step (solvent detergent treatment).2 Furthermore, the authors only refer to a single process step (pasteurization, a virus inactivation step) for Prolastin. Although the Prolastin package insert is referenced,3 there is no mention in the paper of the 3 additional virus removal steps (effluent fractionation, polyethylene glycol precipitation, depth filtration) used in the Prolastin manufacturing process as illustrated in a table on the first page of the Prolastin package insert. A comparison from the respective package inserts of the procedures used for the 2 products, therefore, shows that there are, in total, 3 process steps for the removal and/or inactivation of viruses in the case of Aralast and 4 for Prolastin.
The authors then listed the accumulated log reductions in viral load following the process steps used to produce Aralast (Table 2, page 1865), whereas the corresponding data for Prolastin are reported as not available. However, the Prolastin virus reduction data are clearly shown in the table referred to above on the first page of the Prolastin package insert.3 While it is inappropriate to compare virus log reductions except in head-to-head comparisons using the same test methodology in the same laboratory, it is interesting to note that the virus log reductions reported in Prolastin's package insert compare very favorably (ie, greater than) with the virus log reductions reported in the Aralast package insert (Table 1).
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The statement by Louie et al. that Aralast has an extra safety measure compared with Prolastin is inaccurate and does not reflect the current purification procedures used in the manufacturing processes for the 2 products. Moreover, the available experimental and historical evidence shows that Prolastin has a long history of exceptional safety. Two million infusions have been administered over the 17 years that Prolastin has been available to treat AAT deficiency. In addition, there have been no documented reports of transmission of viruses or other infectious agents to individuals receiving Prolastin either in clinical studies or during postmarketing surveillance.4 It will be many years before the same claim can be made for Aralast as a new product on the market.
Footnotes
Comments on articles previously published are submitted to the authors of those articles. When no reply is published, either the author chose not to respond or did not do so in a timely fashion. Comments and replies are not peer reviewed.-ED.
References
1-protease inhibitor for treatment of -antitrypsin
deficiency. Ann Pharmacother 2005;39: 1861-9.
Epub 11 Oct 2005. DOI 10.1345/aph.1E061
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