Prevention
of Mother-to-Child Transmission of Multidrug-Resistant HIV Using T-20 Plus Tipranavir
 Without
treatment, the rate of mother-to-child HIV transmission
around the time of delivery is about 25%. AZT
(Retrovir) and nevirapine
(Viramune) can dramatically reduce the risk of vertical transmission, but
the best prophylactic therapy for women with multidrug-resistant virus remains
unclear. In such cases, clinicians prescribe newer antiretroviral agents for which
there is limited clinical trial or anecdotal data concerning their use during
pregnancy and their effects on the fetus.
In the June 26, 2006 issue
of AIDS, researchers reported on a case in which perinatal prophylaxis
using T-20 (enfuvirtide, Fuzeon)
plus tipranavir (Aptivus)
may have helped prevent mother-to-child HIV transmission. There is only limited
information on the use of T-20 during pregnancy, and the use of tipranavir during
pregnancy has not previously been reported. In
this case report, the patient was a 33-year-old woman, pregnant for the first
time, who presented for care at 27 weeks gestation. She had been on various antiretroviral
regimens since 1996 without ever achieving sustained virological suppression.
At the time of presentation, she was taking d4T
(Zerit), tenofovir (Viread),
and lopinavir/ritonavir (Kaletra),
but her adherence was inconsistent. While her CD4 count was still 380 cells/mm3,
she had a viral load above 200,000 copies/mL. After
genotypic testing revealed extensive drug resistance, she was started on a “mega-HAART”
regimen that included T-20 and
tipranavir plus AZT,
3TC (Epivir), abacavir
(Ziagen), and tenofovir.
Testing did not show extensive resistance to non-nucleoside reverse transcriptase
inhibitors (NNRTIs), and this class of drugs was reserved for prophylaxis for
the newborn baby. The woman was hospitalized to allow for directly observed therapy
and close monitoring of potential adverse events. She initially experienced severe
nausea and weight loss, but after a brief period of drip-feeding, the nausea disappeared
and she was able to resume a normal diet. At
34 weeks gestation, the woman underwent a Cesarean section after rupture of membranes.
During the procedure, she received high-dose
AZT. At the time of delivery, her viral load was 73 copies/mL. She gave birth
to a healthy, albeit premature, infant, who immediately started prophylaxis with
lopinavir/ritonavir, nevirapine,
and 3TC, continuing for four
weeks. The baby tolerated therapy well, but had a hemoglobin level at the low
end of the normal range. The infant’s viral load was below 50 copies/mL at birth
and remained undetectable at 26 weeks of age. While
the intensive “mega-HAART” regimen may have prevented HIV transmission in this
case, a case of perinatal transmission of multidrug-resistant virus from a woman
taking T-20 was recently reported,
despite the fact that the mother achieved an undetectable viral load. This woman
also experienced virological failure on a regimen containing lopinavir/ritonavir
during pregnancy and her resistance profile was comparable.
This woman did not receive tipranavir and did not have a Cesarean section, which
has been shown to further reduce the risk of transmission. Studies
have shown that tipranavir remains active against HIV that is resistant to other
protease inhibitors. While tipranavir was associated with fetal toxicity in rats,
the authors of the current case report judged that the potential benefits of tipranavir
outweighed the risks, and the woman’s baby showed no evidence of birth defects. 07/7/06 Reference
A
Wensing, C Boucher, M van Kasteren, and others. Prevention of mother-to-child
transmission of multi-drug resistant HIV-1 using maternal therapy with both enfuvirtide
and tipranavir [Correspondence]. AIDS 20(10): 1465-1467. June 26, 2006.
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