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
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.
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.