Chat transcript: Dr. Jack Killen on AIDS treatment

July 15, 1999
Web posted at: 1:27 p.m. EDT (1727 GMT)

(CNN) -- The following is an edited transcript of a chat with Dr. Jack Killen, director of the AIDS division at the National Institute of Allergy and Infectious Diseases. Killen joined us from Washington, D.C., to discuss a new study on an affordable AIDS drug that can significantly reduce the number of babies born with HIV. The chat took place Wednesday, July 14, 1999.

Chat Moderator: Dr. Killen, please tell us about the study that is in the news today.

Dr. Killen: HIVNET 012 compared two different regimens of antiviral drugs given late in pregnancy and in the first day of the baby's life to determine their usefulness in preventing HIV infection from mother to infant. A single dose of nevirapine to the mother and to the infant resulted in a 48 percent decrease in transmission compared to a short course of AZT. The regimen is very easy to administer and very inexpensive and will hopefully make a major contribution to stemming the HIV epidemic in the developing world.

Chat Participant: Since AIDS in Africa has become an almost genocidal epidemic, is there hope that this new drug will be widely distributed on the continent by world health organizations?

Dr. Killen: We have yet to see how widespread distribution will be, but there is every reason to believe that the cost and simplicity of this regimen will make it a real option and will lower one of the big obstacles to effective control of the epidemic in children.

Chat Participant: Can the research used to find this treatment be used to shorten the search for a cure?

Dr. Killen: Interesting question.... We think of this as prevention of disease rather than infection. The fact that such a brief course of intervention can prevent the establishment of infection implies that there are other means of prevention that can be found. That is, that there are factors which we don't understand, but it is fairly easy to block infection.

Chat Participant: Why is the treatment so inexpensive?

Dr. Killen: The drug is very simple to synthesize, and it is only two doses!

Chat Participant: Dr. Killen ... would this treatment be the same even in the case of multiples? Or would the dose be higher and/or any risk greater?

Dr. Killen: I assume you mean multiple births. There were some twins (11 sets) and triplets (one set) born during this study, but I don't have the outcome in those cases here. One would expect the benefit to be essentially the same. Also, one would definitely use the regimen in subsequent pregnancies.

Chat Participant: Can you describe the treatment process? How often is it used?

Dr. Killen: There is a single dose of nevirapine given to the mom at the onset of labor, and a single dose given to the baby shortly after birth. That's it!

Chat Participant: How late in the pregnancy is the treatment effective?

Dr. Killen: That is one of the things which is very exciting about this study. The drug is first administered when the mother goes into labor. So it is not necessary to have prenatal care or sophisticated medical systems, which is often the case in poorer countries.

Chat Participant: What are the known side effects?

Dr. Killen: The side effects seen in this study were very few and very mild, mostly mild anemia and skin rashes in the infants, all rare. The infants will be observed for at least 18 months in follow-up.

Chat Participant: What is the risk of transmission with no treatment?

Dr. Killen: Good question ... though we don't have an exact answer from this study ... but it is likely in the 30-40 percent range in a breast-feeding population.... It is affected by a number of factors such as the seriousness of HIV disease in the mother and the mode of delivery.

Chat Participant: Have the results you speak of been duplicated by any other studies, or is this another one of those "miracle cures" that will disappear once the results cannot be repeated?

Dr. Killen: This is the first report of this regimen; other trials are underway. We have certainly seen results exactly like this with other drugs in the same setting, and the strength of the findings is very high.

Chat Participant: Is a vaccine for AIDS possible?

Dr. Killen: We definitely believe that a vaccine is possible, given a lot of recent data from monkey studies. A vaccine is, in the end, the only really viable answer to the epidemic on a global scale. The results of this trial deal with a limited group of people affected by the epidemic -- namely children born to mothers already infected. Our ultimate goal is to prevent the mother from becoming infected in the first place.

Chat Moderator: Does the use of the drug help reduce the risk of transmission through breast-feeding?

Dr. Killen: It appears that it does, on this early analysis. The percent of infants infected at birth was 8.2 percent in the nevirapine arm and 10.4 percent in the AZT arm.... By 14 weeks 25 percent were infected in the AZT arm, and only 13 percent of those who had received nevirapine. This implies strongly that there was an effect during breast-feeding after birth.... Further trials will examine this more closely.

Chat Participant: Dr. Killen, since not all births from an HIV mother end up HIV+, would the treatment still be administered to both mom and baby? And lastly ... do you support HIV testing in everyone’s prenatal care?

Dr. Killen: Yes, that is how this treatment was given, since we don't have any way of knowing which babies will become infected. It has been suggested, in fact, that one way to use this regimen in areas where HIV is highly prevalent and testing is not available would be to give it to ALL pregnant women, since it appears to be so safe. More research is needed before this could be recommended, however.

Chat Participant: Dr. Killen, can you give any statistics of how many babies born in America are infected, just this year alone?

Dr. Killen: In the U.S., the estimate is 400-500 per year. Globally, it is estimated to be 1,600-1,800 per DAY.

Chat Participant: Is this the same drug as Viramune, approved by FDA about 3-4 years ago?? And why are we only now hearing about it ?

Dr. Killen: The drug was approved for other indications by the FDA several years ago. This study was only completed last week. It establishes the basis for a new use for the drug.

Chat Participant: Do you have concerns about the generation of babies that will be born without the disease but will probably lose their mothers to the disease before becoming adults, if the drug is widely adopted?

Dr. Killen: Yes, of course, this is a serious problem. It speaks, again, to the urgent need for an effective, preventive vaccine. In our conversations with African government officials, they understand this but are very anxious to stem the epidemic in children.

Chat Participant: If the nevirapine is successful in preventing a baby being born with HIV, what if any improvements will they enjoy in the future in the way of immunity to HIV?

Dr. Killen: Great question! We are currently studying this very issue in other groups of children. It could hold important clues for a preventive vaccine.

Chat Participant: Could the drug improve the life span of the babies born HIV-positive?

Dr. Killen: It is likely that the course of disease in the babies who are born infected will not be altered by this single dose of drug, unfortunately. We will want to follow them carefully to learn whether this is the case.

Chat Participant: Is the drug already approved for commercialization?

Dr. Killen: The drug is approved in the United States for other indications. It is also approved for marketing in some other countries, although I do not have a list in front of me. That will be important in how fast the regimen can be put into general use.

Chat Participant: Dr. Killen, thank you for answering my prior question. Being that an unborn child shares a direct common blood supply with the mother, how on earth do these drugs prevent transmission?

Dr. Killen: In fact, the mother and the infant do not share a common blood supply. Their bloods are separated by the placenta, which filters nutrients and oxygen going into the fetus and takes away waste products.... The drug goes across this barrier and is believed to inactivate the virus before it can establish infection.

Chat Participant: Anyone hear of the drug called RETICULOSE?

Dr. Killen: Sorry, I don't know anything about that drug.

Chat Participant: The mother still has to know that she has the virus, and many pregnant mothers in needy countries don't know.

Dr. Killen: Yes, you are correct. This is an important factor in being able to put this regimen into widespread use. Either we must find cheap, effective ways to provide screening during pregnancy, or we could treat ALL pregnant women, at least those in areas such as southern Africa where up to 30 percent of pregnant women are infected.

Chat Participant: Doctor K, at what point during pregnancy would this drug be given to the mother?

Dr. Killen: Nevirapine is given at the onset of labor. This is one of the most important aspects of this study, since most women in Africa do not receive any prenatal care.

Chat Moderator: How long did the study follow-up with the babies?

Dr. Killen: This is an interim analysis. We have good data to 14 weeks of age. As we follow the children longer, we will have much more information. We do know that most mother-to-infant transmission occurs during the first several months of life.

Chat Participant: Dr. Killen, what are the side effects of this drug to mother and baby from trials, especially long-term ?

Dr. Killen: Short-term side effects are very mild and rare -- mild anemia and skin rashes in the babies. We are following the children to gather information on longer-term side effects. Given that they receive such a small amount of drug, it is extremely unlikely that anything serious will be found.

Chat Participant: Is there anything in the original history of Viramune that would lead you to be skeptical of these initial results?

Dr. Killen: Not really.

Chat Participant: Dr. Killen, why any drugs then, if the placenta acts as a barrier to prevent transmission? What function do the drugs perform?

Dr. Killen: The drugs do go across the barrier. The virus, for the most part, does not. The drug could act by inactivating virus, which does uncommonly get into the newborn, either before or after it crosses the placenta.

Chat Participant: Has the World Health Organization or any other major health organization evaluated the study and its results?

Dr. Killen: We have shared the results with the UNAIDS, WHO and UNICEF. They are all as excited as we are. The data will be examined carefully at a large international conference in September.

Chat Moderator: Any final comments?

Dr. Killen: I do want to congratulate the Ugandans who did the actual work to bring these exciting results to fruition, and of course thank the women who volunteered for the study.

Chat Moderator: Thank you, Dr. Jack Killen, for joining us today.

Dr. Killen: Thank YOU! This was fun. I enjoyed the opportunity.

Please check our chat calendar for upcoming health chats. See you there!