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Cidofovir for Cytomegalovirus Retinitis
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Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
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TO THE EDITOR:
The demonstration of the effectiveness of cidofovir to treat cytomegalovirus (CMV) retinitis adds a welcome third drug to the list of anti-CMV therapies. However, it is most disturbing to find that the two clinical studies of this compound [1, 2] compared it with no treatment (“deferred therapy”).
There is no doubt that the natural history of untreated CMV retinitis is one of relentless progression and that ganciclovir [3] and foscarnet [4] are both effective. Therefore, the withholding of proven therapy (even with close follow-up) in the context of a clinical trial to demonstrate the effectiveness of cidofovir is unacceptable. The rationalization that only patients with peripheral retinitis were enrolled is irrelevant and of questionable prudence because 4 of 23 patients in the no-treatment group developed sight-threatening retinitis and another patient developed extraocular CMV infection.
The provision of informed consent by the participants of these studies does not render the withholding of proven therapies for the purposes of demonstrating cidofovir's effectiveness any less unethical. I must admit that I was surprised that these studies were approved by the study institutions' ethics review boards. Similarly, regulatory requirements and the fact that previous studies of anti-CMV therapies have been compared with placebo provide no justification for the nontreatment of an opportunistic infection in an experimental protocol. We would not consider withholding therapy for Pneumocystis carinii pneumonia or cryptococcal meningitis to prove that a new compound is efficacious.
Surely, there must have been enough suspicion of the potential effectiveness of cidofovir to allow for a direct comparison with ganciclovir or foscarnet. This would have been far more ethically acceptable and would have gone far to delineate the potential role of cidofovir in the treatment of CMV retinitis.
Stephen Kravcik, MD, FRCPC
Ottawa General Hospital; Ottawa, Ontario K1H 8L6, Canada
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
- Copyright ©2004 by the American College of Physicians
