AIDS TREATMENT NEWS Issue #214, January 6, 1995
On January 5, Syntex (a Palo Alto, California pharmaceutical
company recently acquired by Hoffmann-La Roche) announced that
the U.S. Food and Drug Administration had approved oral
ganciclovir for marketing.
Ganciclovir (Cytovene() has long been an approved drug widely
used for treating CMV retinitis, which if untreated causes
blindness in persons with advanced AIDS. A major disadvantage
of ganciclovir has been that it had to be given intravenously
every day. In addition to the expense and inconvenience, the
intravenous administration can increase certain side effects,
including serious infections.
Treatment with ganciclovir involves two stages: induction
therapy (usually twice-daily intravenous infusions for two to
three weeks), followed by maintenance therapy, usually one
infusion per day. Eventually the maintenance therapy is likely
to fail; then the induction may be repeated, or the patient may
be treated with another intravenous drug, foscarnet.
The newly-approved oral drug can be used for maintenance in
some patients; however, intravenous treatment is still
necessary for induction.
Maintenance with the oral drug is somewhat less effective than
with the intravenous; in clinical trials, the average time to
disease progression was five to twelve days faster with the
oral drug. Therefore the FDA indicated oral ganciclovir only
for those "for whom the risk of more rapid disease progression
is balanced by the benefit associated with avoiding daily IV
infusions." And many of the side effects of intravenous
ganciclovir are still present with the oral drug, especially
hematological toxicities; therefore blood tests are necessary
with the oral as with the intravenous treatment.
Oral ganciclovir is taken either three times a day or six times
a day, with food.