DOCTORS from St George’s Hospital have found that a new drug for treating HIV infections can prevent pregnant women infected with a drug-resistant form of the virus from transmitting it to their babies.

Two case studies published by a team of virology, paediatric and sexual health experts from the hospital in this month’s AIDS journal show that preventing mother-to-child transmission of HIV can be helped by including a drug called Enfurvitide in the ‘cocktail’ of anti-HIV treatments given to pregnant women who are resistant to HIV medication.

Because a pregnant woman shares her blood supply with her baby, there is always the risk that an infection will pass from one to the other at any stage of pregnancy, though the risk is greatest during delivery.

Figures show anti-HIV therapy has led to an increase in the number of UK patients with resistance to antiretroviral medication. Many patients have at least some degree of resistance to all three classes of antivirals used to treat the disease and the researchers from St George’s Hospital warn that there could be a rise in the number of pregnancies involving women with drug-resistant forms of the virus as a result.

Enfurvitide (or Fuzeon) is a new type of anti-retroviral drug developed by US firm Roche Pharmaceuticals called a fusion or entry inhibitor. The drug attaches large molecules to the outside of CD4 cells (or T-cells) to prevent the HIV virus from hijacking cells and using them to copy itself.

Dr Phillip Hay is an expert in the HIV virus and one of the authors of the research:

“Enfurvitide is a relatively new antiviral drug which has never been used for this purpose before.

“Although we looked at only two cases, the results show there are considerable benefits in making the medication part of anti-HIV therapy for an expectant mother infected with a highly resistant virus.

“Further research is needed but the initial results from this study are promising.”

The drug was given to two pregnant women – one aged 36, the other 33 – who both had multi-drug resistance to HIV.

In both cases, the women gave birth without transmitting the HIV virus to their babies.

St George’s Hospital is a leading centre for the treatment of HIV and AIDS and runs a special pregnancy clinic for women infected with the virus.

In the last ten years, doctors have helped more than 250 women with HIV to give birth. The virus was not known to have been transmitted to any baby in the last five years.