A RANDOMIZED PILOT-STUDY OF ALTERNATING OR SIMULTANEOUS ZIDOVUDINE AND DIDANOSINE THERAPY IN PATIENTS WITH SYMPTOMATIC HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION

A randomized pilot study comparing alternating and simultaneous regime ns of zidovudine and didanosine (ddl) was conducted in 41 patients wit h AIDS or symptomatic human immunodeficiency virus (HIV) infection. Pa tients on each regimen received the same overall amounts of zidovudine and didanosine over time. CD4 cell counts in patients on the simultan eous regimen reached a maximum (mean +/- SE) of 108 +/- 16/mm3 above b aseline (two-tailed P less-than-or-equal-to .0001) and were significan tly higher than in patients on the alternating regimen at all time poi nts during weeks 6-45. At 54 weeks, the CD4 cell counts in the patient s on the simultaneous regimen were still 40 +/- 19/mm3 above baseline. Patients on the simultaneous regimen also had significantly greater w eight gain. While toxicities were generally mild and comparable betwee n the regimens, 1 patient on the simultaneous regimen died of pancreat itis and lactic acidosis. Thus, simultaneous therapy provided more sus tained elevations in CD4 cells than alternating therapy over 1 year an d may be worth exploring in larger controlled trials.