Evaluation for late effects of In Utero (IU) ZDV exposure among uninfected infants bom to HIV+ women enrolled in ACTG 076 & 219

Background/Aim: ZDV is widely used in the US for preventing HIV mother-infant transmission (MIT). Late effects of IU ZDV exposure are unknown. IU ZDV exposed infants were evaluated for adverse effects 2yrs after the conclusion of 076. Methods: 66% of infants randomized to ZDV or PL intrapartum & 6wks post birth (076), were enrolled in ACTG 219, a cohort study providing follow-up for PACTG patients (pts) thru 21yrs. Data assessing growth, cognitive, immune status, & other organ system toxicity are collected every 6mo for HIV+ & HIV- infants <24mo of age & yearly thereafter (except cognitive testing). Baseline echocardiogram & fundoscopic exams were collected at 36mo. Results: Data were available on 230 seroreverters (121 ZDV exposed). Pts median age 3.4yrs (range 2.4-4.9). Mat & infant characteristics are similar to the original 076 pts No unexpected opthamology diagnosis (dx), cardiac dx, neoplasms or other organ system dx were reported. CD4 & CD8 measurements, growth, & cognitive data (see below) reveal no difference for ZDV vs. PL infants. Bayley Scores McCarthy Scores months mental motor GCI ZDV PL ZDV PL ZDV PL 18 (15-21) 97.2 93.5 99.0 97.4 NA NA 24 (21-30.5) 94.0 89.8 101.6 101.5 NA NA 36 (28.5-54) NA NA NA NA 87.6 87.6 Conclusion: 076/219 pts evaluation reveal no adverse effects for ZDV IU exposed infants followed as long as 4yrs. While data are reassuring, continued prospective evaluations of perinatally exposed infants (to ZDV & other antiviral or immunotherapy agents) are critical to assess long term safety of successful HIV MIT prevention strategies.