AIDS patients for whom the drug AZT no longer offers help in fighting the deadly infection can choose either of two backup drugs for continued help, according to a UC San Francisco study.
But neither of the two drugs is as effective as the early treatments with AZT, which decline in effectiveness over time.
The test on 467 people with AIDS for whom the drug AZT had lost its effectiveness found that two other drugs offer the same help in fighting infection.
The drugs tested were didanosine (DDI) and zalcitabine (DDC), both of which have been made available by the U.S. Food and Drug Administration under a program to accelerate experimental AIDS drugs onto the market.
An alternative to AZT is needed because its benefits sometimes fade in two to three years for people with no symptoms, and within 12 to 18 months when the number of infection-fighting cells has dropped significantly.