Combination Antivirals: ddC Plus AZT Approved

The U. S. Food and Drug Administration has approved the drug
ddC for treating people with advanced HIV infection,
including AIDS -- but only for use in combination with AZT.
This approval, effective June 19, 1992, was based on two
small, preliminary studies which showed much greater
improvement in T-helper counts with the combination treatment
than would be expected with AZT alone. (But a large study
comparing ddC alone with AZT alone was stopped early, because
the AZT worked much better; those treated with AZT had a
lower chance of dying of AIDS than those treated only with
ddC. That is why ddC was approved for use in combination with
AZT, but not for use by itself.)

"ddC" is an abbreviation for the chemical name 2,3'-
dideoxycytidine; it is also called zalcitabine (generic drug
name) or HIVID (brand name). The drug, developed as an AIDS
treatment by Hoffmann-La Roche, was first approved in
Austria, on April 7, 1992; Roche has also applied for
approval in over 20 countries in Europe.

ddC is inexpensive to manufacture, probably pennies a day.
The reason is that very low doses are used; one kilogram is
enough to treat 1,000 people for more than a year. But
unfortunately, ddC may not be practical as a low-cost
treatment which could be available anywhere in the world,
since AZT is also required. AZT costs more to manufacture,
and it also costs more to use, since blood tests are required
to use it safely.

The main side effect of ddC is peripheral neuropathy, which
causes numbness, tingling, burning, or pain in the hands or
feet. If moderate discomfort occurs, it is important to stop
the drug immediately. Sometimes half-dose treatment can
resume later.

For more information about using ddC, see the "package
insert" for the drug, which is written for physicians. A
package insert is available in the United States, or in other
countries where the drug has been approved.