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Being Alive

NEW DATA ON DDC VS. DDI VS. AZT: AZT vs. ddI




 

Being Alive 1993 Feb 5: 8

While waiting (endlessly, it seems) for something better, we continue to amass bits and pieces of new information about the nucleoside-analogue antiviral drugs (AZT, ddI, ddC and the soon-to-come second generation d4T and 3TC). In the past two months, the National Institutes of Health (NIH) has released summary results of two large comparative studies involving ddI, AZT, and ddC.

AZT VS. DDI The first was the report from ACTG 116A, comparing two doses of ddI (750mg/day and 500mg/day) to the standard dose of AZT (600 mg/day) in persons with AIDS or ARC who had not previously taken AZT at all or who had taken it for less than 16 weeks. Results released earlier (ACTG 116B and 117) involved people who had taken AZT for longer than 16 weeks, showing a modest superiority for ddI (at the 500mg/day dose) compared to AZT in the ARC participants and comparability to AZT in the AIDS patients. Subsequently ddI's approved uses were expanded to cases of advanced HIV infection who had prolonged prior AZT use, even without signs of failure or intolerance.

The new results addressed whether ddI was roughly equivalent to AZT in those with no or little prior AZT use. All participants had initial T4 cell counts of less than 200 (or less than 300 with an AIDS diagnosis or advanced ARC symptom). The findings were mixed. The central result was that AZT was superior to ddI in delaying disease progression for those who had never taken AZT. In this group, 18% of those on AZT had a new OI or died within one year compared to 29% on ddI 500mg and 31% on ddI 750mg.

However, ddI was superior in another subgroup, those who had taken AZT for more than 8 but less than 16 weeks. For those on AZT less than 8 weeks, there was no significant difference. The 500mg ddI dose (in the sachet form equivalent to 400mg/day of the tablet form) was superior to the 750mg ddI dose.

As to toxicities, 7% of those on ddI 500mg had pancreatitis in a year's time compared to 4% on AZT (indicating to the NIH that some of the pancreatitis thought to be associated with ddI may in fact be a consequence of advanced HIV infection itself). There were no significant differences between the two drugs in incidence of peripheral neuropathy or of anemia (low red blood cell counts). AZT, however, was associated with significantly more frequent low counts of an important kind of white blood cells (granulocytopenia).

ACTG 116A had 617 participants. Overall, 8% were women, 13% African-American and 12% Hispanic. 



 




Information in this article was accurate in February 5, 1993. 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.