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Kaposi's Sarcoma: Possible Foscarnet Treatment?




 

AIDS TREATMENT NEWS #215, January 20, 1995

Foscarnet (Foscavir) is an antiviral used to treat CMV (cytomegalovirus) infection; it is also used in serious cases of acyclovir-resistant herpes simplex. It is active not only against CMV (which is a member of the herpesvirus family) and herpes simplex, but also against all other known herpesviruses; in addition it has some anti-HIV activity, although it is not generally used as an anti-HIV treatment. Foscarnet is often the initial choice of anti-CMV treatment in Europe, while ganciclovir is usually the initial choice in the United States; this difference appears to be due to historical reasons, as foscarnet was developed by Astra, a Swedish company, while ganciclovir was developed in the U.S. Foscarnet must be given intravenously with an infusion pump, and can cause many serious side effects -- especially kidney toxicity, which occurs to some degree in many patients treated; the drug must be used by a physician who has experience with it. Another disadvantage is that the drug is very expensive.

Until recently there was no reason to think that foscarnet would have any use in treating Kaposi's sarcoma (KS). But last year a laboratory study, published in December 1994, found evidence that KS might be caused by a previously- unknown herpesvirus(1) (see AIDS TREATMENT NEWS #213, December 23, 1994). And another article, also published in December 1994,(2) reported on a pilot study of five patients, which was conducted after physicians noticed that KS regressed in two patients who were treated with foscarnet for other purposes. Three of the five patients in the pilot study had a long-term remission of KS, after a single 10-day treatment (or in one case, two 10-day treatments) with foscarnet; the lesions disappeared slowly over several months. In the other two patients, the disease progressed despite the treatment. KS regressions without treatment are fairly rare. (These five cases were the ones reported at the recent conference in Glasgow, Scotland, as mentioned in AIDS TREATMENT NEWS #213.) The five patients in the pilot study had low CD4 (T-helper) counts (24, 26, 270, 6, and 24) when treatment began. The two who progressed had ongoing, active opportunistic infections at the time; the three who had long-term regression did not. All five were also being treated with AZT following the course of foscarnet.

We talked to Linda Morfeldt, M.D., Dr. Med. Sc., of the Karolinska Institute in Sweden, who organized the pilot study. She said that the results so far suggest: (1) The effect of foscarnet on KS is not proven; however, other small studies are now being designed to confirm or to rule out the early findings; (2) The researchers suspect that the drug may be effective in relatively early KS which is confined to the skin and mucous membranes (even if the CD4 count is low) -- but not effective, or less effective, in advanced KS; and (3) Patients who also have ongoing active infections, such as CMV organ disease, pneumocystis, MAC, or fevers of unknown origin, may not respond to foscarnet as a KS treatment; but the KS may possibly respond if the opportunistic infections are successfully treated first.

AIDS TREATMENT NEWS (December 23 issue) asked our readers to let us know of any experience of persons with KS who used foscarnet, regardless of the outcome; so far three people have contacted us as a result. One had fairly mild KS since June 1992, but he was still getting new lesions, and those treated with liquid nitrogen would re-appear. He started foscarnet for CMV retinitis in mid January; by early March the KS had mostly disappeared. After six weeks on foscarnet, there were no new lesions, and those treated with liquid nitrogen did not return.

Another person, before he started using foscarnet, had about 20 KS lesions; these had been removed successfully with Velban or liquid nitrogen. Since he started using foscarnet, no new lesions have appeared.

The third person had only one small KS lesion, which was removed and biopsied in 1992. For three years since he has been on foscarnet, and no new lesions have appeared.

Early KS Foscarnet Study Now Recruiting in New York A 20-patient study of foscarnet treatment for early KS is planned at New York University Medical Center by Drs. Alvin Friedman-Kien, Miriam Keltz, Abraham Chachoua, Geoffrey Chazen, Linda Morfeldt, and others. The goal is to confirm whether or not foscarnet can have any therapeutic benefit in treating KS.

To answer this question most effectively, this study is seeking patients with early KS -- approximately five lesions, and for no longer than six months, and with no prior treatment for KS. Also, they must have a CD4 count of at least 50.

References 1. Chang Y, Cesarman E, Pessin MS, Lee F, Culpepper J, Knowles DM, and Moore PS. Identification of herpesvirus-like DNA sequences in AIDS-associated Kaposi's sarcoma. Science. December 16, 1994; volume 266, pages 1865-1869.

2. Morfeldt L. and Torssander J. Long-term remission of Kaposi's sarcoma following foscarnet treatment in HIV- infected patients. Scandinavian Journal of Infectious Diseases. December 1994; volume 26, number 6, pages 749-752.



 


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Information in this article was accurate in January 20, 1995. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.