Single dose nevirapine under review
The Medicines Control Council has recommended that nevirapine no longer be the only antiretroviral drug being offered to pregnant HIV positive mothers to prevent them passing the virus on to their newborn babies.
The Medicines Control Council (MCC) has recommended to government that a single dose of nevirapine is not effective in the prevention of mother-to-child HIV transmission (PMTCT).
This decision is based on concerns about the development of drug resistance to nevirapine, which could undermine the national anti-retroviral programme that is currently being rolled out in the country. Nevirapine is one of the drugs being offered to AIDS patients.
Health ministry spokesperson Sibani Mngadi said a decision on the way forward will be made after the international AIDS conference, currently taking place in Bangkok.
“There are a number of presentations on effective regimens on PMTCT being made in Bangkok. We will watch these with interest and the health minister will convene a meeting after Bangkok to decide on the way forward,” said Mngadi, speaking from Bangkok.
Mngadi said he could not say whether nevirapine would be dropped altogether or whether it would be used in combination with other drugs.
The MCC said its decision was based on the fact that “nevirapine leads to significant resistance in mothers and babies when used as a monotherapy”, with “recent studies conducted in South Africa using nevirapine as a monotherapy showing significant resistance of up to 50%”.
According to MCC Registrar Precious Matsotso, the MCC decided at a meeting on July 2 that “mono-therapy is no longer allowed, and that combination therapy be used.”
However, Kevin McKenna, spokesperson for Boehringer Ingelheim, which makes nevirapine said his company felt that it had “satisfactorily answered the MCC’s questions about the efficacy and safety of nevirapine”.
But McKenna added that it was clear from a meeting of the health minister and her provincial counterparts (MinMEC) which he had attended two weeks ago, “that things were moving in the direction” of nevirapine being phased out as a single regimen.
“We obviously do not share the view [that a single dose of nevirapine poses a health risk] and would like to get into discussion with government and the MCC about the way forward,” said McKenna.
Andy Gray, senior lecturer in pharmacology at the Nelson Mandela School of Medicine in KwaZulu-Natal, said there were many “ifs and buts” that still needed to be answered.
“It is unclear whether the level of resistance to nevirapine would result in clinical failure if a woman later went on to combination therapy,” said Gray.
Combination therapy being offered as part of government’s comprehensive plan to treat HIV/AIDS is a cocktail of three different classes of antiretroviral drugs. Each drug acts differently on the HI virus.
Gray said there was some concern that there could be “cross-resistance”, meaning that nevirapine resistance could also affect the other drug in its class (the non-nucleoside reverse transcriptase inhibitors) on offer in the national programme, namely efavirenz (brand name, Stocrin).
“There are lots of queries. It is generally accepted that combination therapy is more effective than a single dose of nevirapine in preventing mother-to-child transmission of HIV. But this can mean that women need to start therapy some time before delivery. So what do we do with the HIV positive women who present in labour?” said Gray.
Meanwhile, Health minister Manto Tshabalala-Msimang told the Bangkok conference over the weekend that government had been forced by civil society organisations to prescribe nevirapine before it had completed its own investigations.
This was in reference to the Constitutional Court ruling in 2002 compelling government to offer nevirapine at all public hospitals not just at 18 pilot sites, following court action against government by the Treatment Action Campaign’s (TAC).
However, TAC’s Nathan Geffen said that “single-dose nevirapine for mother-to-child transmission prevention was the government’s choice, not TAC’s as this was the chosen regimen for the pilot sites that preceded the MTCT court case.”
“TAC’s stance is that more effective regimens than the single-dose nevirapine should be introduced into the public sector wherever possible,” said Geffen.
“Where there is a current lack of capacity, single-dose nevirapine regimen is the minimum acceptable regimen for mother-to-child transmission prevention.”