AEGiS-13IAC: Perinatal HIV prevention trial (PHPT), Thailand: simplified and shortened zidovudine prophylaxis regime as efficacious as PACTG076.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

Perinatal HIV prevention trial (PHPT), Thailand: simplified and shortened zidovudine prophylaxis regime as efficacious as PACTG076.

Int Conf AIDS 2000 Jul 9-14; 13:16 (abstract no.. LbOr3)

Lallemant M, Jourdain G, Le Coeur S, Kim S, Karnchanamayul V, Hansudewechakul R, Putiyanun C, Vithayasai V
Institut National d?Etudes Demographiques, Paris, France.

BACKGROUND: To facilitate ZDV use for the prevention of perinatal HIV in resource limited settings, the optimal treatment duration needs to be determined.

METHODS: Multicenter, randomized, 4 arm, double-blind equivalence trial to compare safety and efficacy of maternal ZDV starting at 28 wks gestational age (300mg bid; 300mg q3hr oral labor dose) and 6 wks infant treatment (2 mg/kg q6hrs) (LL for Long-Long, the PACTG076-like reference arm), with maternal ZDV starting at 35 wks and/or infant ZDV shortened to 3 days (Long-Short, Short-Long, Short-Short). Infants were formula fed. Endpoints: DNA-PCR at 1, 45, 60, 180 days. Following the 1st safety interim analysis, SS was stopped, and enrollment continued in in LL, SL and LS. Final accrual: 1437 women. We report preliminary Kaplan Meier estimates of the transmission rates (TR) stratified by enrollment period and based on 95% of the endpoints.

RESULTS: TR prior to protocol amendment were 4.1% (95% CI: 1.4-6.7) in LL and 10.6% (6.5-14.5) in SS (p=0.004), confirming the decision to discontinue SS after the first interim analysis. TR for the whole study period were 6.7% (95% CI: 3.7-9.7) in LL, 5.7% (3.2-8.3) in LS, 8.4% (5.3-11.5) in SL. While equivalence between LS and LL was established, equivalence with SL was borderline. Secondary analysis showed that shortening the maternal treatment was associated with reduced overall efficacy and higher infection rate at birth (TR: 5.0% in short maternal treatment, 1.8% in long).

CONCLUSION: The LS and LL regimen appear safe, easy to comply with, and equally efficacious. Both are simpler to implement and much less costly than the original PACTG076 regimen. While 6 wks ZDV in infants may not add benefit when mothers receive long treatment, it may prevent some infections when mothers receive shorter treatment. [NIH 5R01HD 33326 & Fogarty International, USA; MOPH, Thailand; IRD & INED, France; Glaxo-Wellcome provided study drug; Roche provided Amplicor kits].

Keywords: AEGIS, Zidovudine, HIV Infections, HIV Seropositivity, Parturition, Evaluation Studies, Labor, Obstetric, Treatment Outcome, Double-Blind Method, Delivery, Obstetric, Drug Therapy, Combination, Thailand, France, Infant, Human, Female, Pregnancy, prevention & control, surgery, therapy, drug therapy, AIDS
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