Third International Congress Drug Therapy in HIV Infection 3-7 November 1996 Glasgow, UK

INTRAPARTUM ZIDOVUDINE(ZDV) INFUSION ALONE FAILED TO REDUCE MATERNAL HIV-1 VIREMIA AND VERTICAL TRANSMISSION IN HIV-1 INFECTED PREGNANT WOMEN WITH NO PRIOR ANTENATAL CARE

Virutamasen P¹, Limpongsanurak S¹, Ruxrungtham Kiat¹, Thisayakom U¹, Thaithamyanond P¹, Reinprayoon D¹, Hanvanich M¹, Likitnukul S¹, Sathapompongse K², Chuansanti S³, Nimkam S⁴, Phanuphak P^1
1Chulalongkom University Hospital; ²Vajira Hospital; ³Taksin Hospital; ⁴Bhumipol-Adulyadej Hospital; Bangkok, Thailand

Int Cong Drug Therapy HIV 1996 Nov 3-7;3:Abstract No. OP5.2
AIDS 1996, Vol. 10 (Suppl. 2);S13

PURPOSE OF THE STUDY: In Thailand, the risk of vertical transmission of HIV-1 infection is approximately 24-42 %. However, a significant number which is up to 30 % of HIV-1 infected pregnant women walked in for delivery without previous antenatal care (ANC). Thus, the ACTG 076 ZDV treatment regimen could not be implemented in these individuals. An alternative regimen warrants for investigation. This study is to determine the role of intrapartum ZDV infusion alone in reduction of maternal HIV-1 viral load and HIV-1 vertical transmission.

METHODS: Fifteen antiretroviral naïve, HIV-1 infected pregnant women with no prior ANC who were in labor and walked in for delivery were promptly given ZDV infusion 2 mg/kg in the first hour and then 1 mg/kg/hr until delivery. EDTA blood samples were collected from the mothers at entry and within one hour after delivery for measurement of HIV-1 RNA (Chiron® and/or Roche® assay) and were also collected from the infants at birth, 1, 3 and 6 months for HIV DNA-PCR.

RESULTS: All subjects are asymptomatic HIV infection with median CD4 count of 590 /µl (range 123-1,102). Median duration of AZT infusion is 4.1 hrs (range 0.8-13.6). The median plasma HIV-1 RNA before ZDV infusion is 34,026 copies/ml (range 2,282-60,110) whereas, at delivery is 31,920 copies/ml (range 2,370-71,000) (p > 0.05). Four of the 15 infants (27.7 %) had HIV-1 infection evidenced by DNA-PCR. While there are no signifcant differences in the medians of plasma HIV-RNA (29,560 vs 25,600 copies/ml, p > 0.05) or CD4 counts (600 vs 608 CD4 cells/µl, p > 0.05), the duration of ZDV infusion is shorter (2.7 vs 5 hrs, p < 0.05), and the duration of labor is longer (5.3 vs 2.5 hrs, p < 0.05) significantly in the transmitters as compared to the non-transmitters.

CONCLUSIONS: In our preliminary study, the intrapartum ZDV infusion alone failed to reduce both the maternal HIV-1 viremia and the risk of infection in infants. The recent HIV viral dynamic studies suggest that the t_½ of HIV-1 virion is ~5.8 hrs, the too short duration of ZDV therapy (median < 5 hrs) could be a major explanation of the failure. Thus, in HIV-infected pregnant women with no prior ANC, a more potent antiretroviral agent or combination treatment in mothers and/or a post-exposure prophylaxis in infants may be essential and await further investigation.

Presenting author: Ruxrungtham Kiat

1996-11-03
OP5.2

Originally published in AIDS Volume 10, Supplement 2 and hosted with permission of the publisher Lippincott Williams & Wilkins, 250 Waterloo Road, London, SE1 8RD, UK. Tel: +44 (0)20 7981 0700 Fax: +44 (0) 7981 0701

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