{QTtext}{timescale:100}{font:Verdana}{size:20}{backColor:0,0,0} {textcolor:65280,65280,65280}{width:320}{justify:center} {plain} [00:00:00.506] ( Silence ) [00:00:04.076] >> Welcome to the third lecture in this 2009 series [00:00:09.826] on global diseases, Voices from the Vanguard. [00:00:13.156] This is a joint effort between the Center for Tropical and Emerging Global Diseases [00:00:20.236] and the night chair in Health and Medical Journalism, Pat Thomas of the Grady College [00:00:25.786] of Journalism and Mass Communication and I am pleased that each of you is here. [00:00:31.766] I know outside if it is very tempting, the first nice day in about four days. [00:00:38.216] As most of you know, the lecture series is intended to create interest in global diseases [00:00:44.876] across the campus from north to south campus [00:00:48.516] and today we have Dr. Barney Graham, who will talk to us. [00:00:52.696] But let me first remind you that we have a reception immediately following the lecture [00:00:58.536] over in Dennison (assumed spelling) Hall, right next door. [00:01:01.776] The next Voices from the Vanguard will be April 14th and that will be Dr. Jennifer Freidman [00:01:09.336] from Brown University and she will probably talk to us about her work in the Philippines [00:01:15.796] on a variety of neglected tropical diseases.
[00:01:19.926] So tonight, Pat and I have asked Dr. Barbara Schuster to introduce Dr. Graham to you. [00:01:26.746] But before I do that, it is first a distinct pleasure to introduce Dr. Schuster to you. [00:01:34.436] Dr. Barbara Schuster is the new campus dean of the medical college of Georgia, [00:01:39.046] University of Georgia medical partnership, campus in Athens. [00:01:43.916] She is a proven educator, physician and administrator. [00:01:49.506] Barbara comes to us from Wright State University and Ohio and there she chaired internal medicine [00:01:59.426] and has most recently taken a year to work [00:02:03.076] with the American Medical Association in terms of doing some research. [00:02:09.256] So it is a pleasure to introduce her. [00:02:11.156] She is new to the campus and I think it is terrific that she took the time [00:02:16.246] out from putting together her medical school, [00:02:18.636] which is literally what she is doing to be with us tonight. [00:02:22.786] So it is my pleasure to introduce Barbara to you. [00:02:25.966] I would ask you to welcome her and her husband Richard, who is a professor of UGIA's public [00:02:32.186] of college health and they are both here tonight. [00:02:45.796] So please introduce yourself to them too.
[00:02:49.446] ( Applause ) [00:02:49.513] >> Barbara: Thank you very much for that wonderful introduction. [00:02:51.776] My husband is here in the second row with me, so I hope I will get to meet each [00:02:57.246] of you later after Dr. Graham presents. [00:03:00.236] It is really my pleasure to introduce a colleague. [00:03:03.616] I don't know Dr. Graham, but we have mutual friends in Rochester, New York, [00:03:09.786] people who also work in the field of virology, but Dr. Graham is a graduate of Kansas, [00:03:18.106] the University of Kansas where he received his MD degree after graduating from Rice University. [00:03:25.256] He went on to do post medical school work called residency in Vanderbilt [00:03:30.796] and completed a fellowship there after internal medicine in infectious disease. [00:03:35.866] The infectious disease folks are always close to my heart, [00:03:39.296] because had I chosen a specialty I had thought about infectious disease and so microbiology [00:03:45.886] and infectious disease is something I have always had an interest in. [00:03:49.406] He, of course, has you know rose in the ranks, became a professor and has done outstanding work [00:03:55.376] in the fields of RSV, also known as Respiratory syncytial virus and HIV and today he is going [00:04:03.346] to speak to us on the HIV vaccine development,
[00:04:06.616] what is the next step, so please welcome Dr. Graham. [00:04:09.436] ( Applause ) [00:04:09.676] >> Dr. Graham: Well thank you very much and it is my pleasure to be here. [00:04:22.866] I have to tell you a little bit about my connection to Dr. Collin (assumed spelling) [00:04:28.456] because he rescued me during my dissertation work when I was getting my PhD at Vanderbilt, [00:04:34.916] even though I was a virologist and wanted to be a virologist and he was a parasitologist, [00:04:41.206] he helped me finish that dissertation project [00:04:44.576] and I think it may be his only virology paper ever, but he does have one. [00:04:49.616] ( Laughter ) [00:04:51.606] The thing I learned there though that most of the really big ideas about immunology have come [00:04:58.316] out of the parasitology field and it is mostly things borrowed from parasitology [00:05:05.296] that has populated the viral immunology literature [00:05:08.616] and so I owe him a debt for that as well. [00:05:11.566] Okay. And I thought of him not too long ago when I was in Uganda [00:05:27.856] and had an opportunity to go rafting on the Nile River. [00:05:33.076] And they said it was a class five rapids
[00:05:35.926] and so the shisto (assumed spelling) really shouldn't be there. [00:05:38.736] ( Laughter ) [00:05:39.006] Because they should only be present in very calm waters and so we did go rafting. [00:05:44.706] I was at the head of the boat and we had a terrific time [00:05:47.796] and my antibody titer a few months later was negative. [00:05:50.626] ( Laughter ) [00:05:50.736] So I just, but I did think of you during that trip. [00:05:54.906] [00:05:56.046] So why do we need an HIV vaccine, this is the main reason that there is still more [00:06:02.616] than 7,000 infections every day occurring throughout the world and despite the delivery [00:06:09.296] of anti-retro virals in a more efficient way globally, [00:06:13.566] there are still about 10 new infections for every new person that is started [00:06:17.626] on anti-retro virals and if that is the trend, we are never going to be able [00:06:22.976] to treat our way out of the HIV epidemic. [00:06:26.346] [00:06:27.456] Unfortunately, many of these infections are in low and middle income countries and they are [00:06:33.806] in our most vulnerable populations, women and young, young children. [00:06:41.936]
The United States, the epidemic has gotten as much attention recently [00:06:48.006] as I think it should have, but it still is significant. [00:06:51.636] There is still 55 to 65,000 new infections every year and as you see it has moved more [00:06:59.346] into minority populations, more vulnerable populations and it has become a disease [00:07:05.926] of young people particularly within those minority populations. [00:07:10.006] So we do need a vaccine. [00:07:12.626] So why do we think vaccines would work for HIV? [00:07:15.516] The main reason is because of their track record. [00:07:18.736] Vaccines are the most effective and efficient way to managing [00:07:23.876] and controlling infectious disease epidemics [00:07:26.336] and I am showing you just a few examples here of vaccines for viruses. [00:07:31.426] The year of the peak incidence of that infection in the United States, the number of cases [00:07:40.366] at present in those years, for instance, mumps in 1967, almost 200,000 cases. [00:07:46.186] In the early 60s, half a million cases of measles, those diseases have almost vanished [00:07:53.186] and have become very rare, except for last year when there was 7,000 cases of mumps [00:07:59.126] because people stopped taking their vaccines, because they forgot how bad mumps could be.
[00:08:04.566] We have eradicated smallpox that happened in 1980, [00:08:09.316] so no place on earth is having smallpox now and polio is very rare, [00:08:14.776] if ever present, in the western hemisphere. [00:08:17.936] So vaccines do work, vaccines work even [00:08:21.496] when they are partially affective or partially administered. [00:08:24.226] So this is an example from the mumps epidemic, when the vaccine became available in 1967, [00:08:32.346] before very many people were immunized, the epidemic started going away and it is one [00:08:38.186] of our best examples of how just taking a few transmitters and a few susceptible people [00:08:43.576] out of the population, these kinds of epidemics that are requiring a large number [00:08:49.376] of susceptible people for transmission can start going away. [00:08:53.896] So even before the recommendation was made for some people to be vaccinated [00:09:01.976] in a more universal way, the epidemic was vanished. [00:09:06.816] [00:09:08.416] But there are problems for HIV, very significant biological hurdles [00:09:12.866] that have not been accomplished in any other vaccine effort and so HIV has a list [00:09:20.066] of problems, for instance, the lack of natural immunity. [00:09:25.406]
There is not an example of where our natural immunity response was able [00:09:29.736] to fully clear a virus from an infected human being and so the absence of the ability [00:09:35.426] to study the natural clearance mechanisms is not present in HIV. [00:09:39.896] There is also evidence that if you are infected with one strain of HIV, you can be affected [00:09:45.426] with another strain of HIV so natural virus infection doesn't necessarily prevent you [00:09:51.236] from having another natural virus infection. [00:09:54.586] The genetic diversity is difficult for two major reasons, one is the question is what do you put [00:10:01.146] in the vaccine, how do you select the antigens for the vaccine when there are [00:10:04.416] so many tens of thousands of choices to make. [00:10:08.806] And secondly, because if you do become infected, [00:10:11.866] even though you are vaccinated the genetic variation in the virus growing [00:10:16.256] in you can help you escape those immune responses. [00:10:20.066] So it is problematic on both the population and the individual level. [00:10:26.736] Thirdly, there is an infection in a deficit created in the first responders [00:10:33.086] for the immune system, both antigen presenting cells are impacted and the (inaudible) 4 T cell [00:10:40.316] that organizes the rest of the immune response are either destroyed
[00:10:45.146] or their function is diminished and then HIV can infect immune privileged sites like the eye [00:10:54.456] or the immune system has a hard time reaching. [00:10:57.526] It can become integrated into your genome and become latent and so it can exist in a state [00:11:03.656] in which no antigens are seen and the immune response can't see it [00:11:08.306] or it can become sequestered so a lot of HIV [00:11:11.456] in an infected person is actually sitting outside of your cells. [00:11:14.716] It is sitting attached to the outside of the drake (assumed spelling) cells [00:11:17.536] in the lymph nodes and that is not a place it can be cleared by the immune system. [00:11:23.336] And then for vaccine developers, one of the biggest problems for HIV is the failure [00:11:28.016] to induce neutralized antibodies, which is the basis [00:11:30.896] for most effective vaccines that we have today. [00:11:35.746] So I will go through why despite these biological problems, [00:11:40.756] I think it is still possible to have an HIV vaccine and then I will tell you about some [00:11:46.766] of the difficulties we have had in the HIV vaccine development field in the last two years [00:11:51.346] and then at the end I will let you help me decide what we should do next, [00:11:56.516] what should be the next step.
[00:11:59.056] So when you are infected with the virus, it is interesting that despite the diversity [00:12:04.736] of viruses that a person might be exposed to, a typical infection is a single Varian crossing [00:12:12.506] over and infecting the next person. [00:12:15.706] We know that because sequencing virus early [00:12:18.216] in that infection period only gives you a single genotype and it doesn't, [00:12:23.716] it takes about 4 to 6 weeks before the genotypic diversity to start developing, [00:12:28.896] so unless a person has ulcer disease, most infections occur from just a single varian [00:12:35.826] and so the transmission efficiency is not that high with HIV. [00:12:39.186] It is not a very contagious virus and it may be a very minimal immune response of the right time [00:12:46.156] and the right place that had a big impact on HIV transmission. [00:12:52.236] So when it infects, it infects usually through a mucosal service, dendritic cell grabs the virus [00:12:58.606] and feeds it to a CD4 T-cell nearby and within just a few hours it is spread [00:13:04.966] and can be detected in regional lymph nodes. [00:13:07.926] Within a few days, it is systemically spread and you can find it in all the lymph nodes [00:13:12.936] in the body and at that time, it achieves a dynamic equilibrium where there is a lot [00:13:18.916] of virus being made and a lot of virus being cleared, but you reach a set point
[00:13:23.936] where you have a steady state virus level, but that process of making virus [00:13:30.136] and killing virus is what eventually erodes and destroys your lymph node architecture [00:13:35.316] and allows you to develop immune deficiency. [00:13:40.206] [00:13:41.236] We know that if we had an antibody that was effective at blocking HIV [00:13:45.646] that could neutralize HIV, we could potentially block infections. [00:13:49.326] That would be our best option. [00:13:50.646] That is how most good viral vaccines work, but as I will explain later in more detail, [00:13:57.686] we do not have antigens identified that can elicit broadly neutralizing antibodies to HIV, [00:14:03.096] so antibodies that can block the most commonly transmitted strains [00:14:06.896] of HIV are difficult to identify. [00:14:11.996] We also know that when we have our normal adaptive immune response, [00:14:17.386] particularly the T cell response, when it happens, it cannot fully clear virus. [00:14:23.286] It just achieves this steady state of virus resistance and we know [00:14:28.666] that in the meantime before that T cell response can occur, [00:14:32.596] this state of latency can be establish in a sequestration. [00:14:39.456]
So the big question for vaccines as we are now working on vaccines is what happens [00:14:44.826] if you move the T cell response sooner. [00:14:47.466] If the adaptive immune response can happen a little bit earlier [00:14:51.156] and a little bit higher magnitude, what effect could that have on virus replication. [00:14:57.206] So when you are infected with HIV, it takes about 3 to 4 weeks for the virus [00:15:02.006] to reach its peak point of virania (assumed spelling) and at that point, [00:15:08.046] the T cell response kicks in and a specialized type of T cell, the CD8 T cell, [00:15:12.516] the killer T cell or the CTL, cytotoxic T lymphocyte is able to recognize the virus [00:15:20.726] and start clearing virus infected cells and that is what reduce the viral load to this set point [00:15:29.606] of virinia that you would have for 7 to 10 years untreated before you developed AIDS. [00:15:37.506] If we had an antibody response preformed antibody response, [00:15:41.256] we may be able to block infection, but it is not likely we will be able [00:15:45.766] to generate antibody response like that in the near future, so most of the vaccines [00:15:49.886] that were being tested right now are T cell based vaccines, [00:15:53.656] hoping that these specialized CT8 T cells that recognized process virus [00:15:59.626] on the surface proteins called
MHC molecules, type 1, class 1, [00:16:03.966] MCH molecules can rapidly clear those virus infected cells and then [00:16:09.816] if potent enough could potentially clear your body and have an abortive infection, [00:16:14.946] but more likely is what is seen in animal models reduce the (inaudible) virinia [00:16:20.546] and achieve a lower set point viral load that results in a very delayed illness progression. [00:16:28.416] You might also have a situation where it doesn't really reduce viral load in the host, [00:16:34.526] but maybe it reduces the output virus and maybe it reduced transmission to the next person. [00:16:40.186] That could also have a beneficial effect on the epidemic and then [00:16:46.086] because things don't always go the way you want them to go, [00:16:49.556] there is also the possibility of disease enhancement. [00:16:52.466] That has been something that has happened with respiratory syncytial virus in the past [00:16:56.086] with measles virus in the past with some (inaudible) viruses in the past. [00:17:00.756] So when you think about starting to make an HIV vaccine and you look back at history, [00:17:10.436] how long does it take to make a vaccine. [00:17:12.516] Can you do it even in one career? [00:17:16.616] And the answer is only if you are lucky and start soon, start early,
[00:17:21.796] because it usually takes decades to develop a vaccine. [00:17:25.806] From the time a virus is discovered to the time the vaccines are available [00:17:29.996] for human use is usually majored in decades. [00:17:33.886] Right now, we are in 25 years and counting with HIV, but there are other difficult viruses [00:17:38.796] with difficult biology that we also still haven't conquered and they are common viruses. [00:17:43.806] Like RSV is more than 50 years, herpes simplex virus is more than 90 years. [00:17:49.256] These are viruses that have properties of latency like herpes or that inactivate some [00:17:55.296] of the early immune responses like RSV that share these properties [00:18:01.396] with HIV, so not all viruses are easy. [00:18:05.906] [00:18:07.226] In 1997, President Clinton gave an address at Morgan State commencement [00:18:12.236] and said maybe we should put more effort behind the HIV vaccine development process [00:18:17.246] and proposed a new center be built on the NIH campus and so that project was started in 98, [00:18:24.576] the building was finished in August of 2000 and we started occupying these laboratories. [00:18:30.746] I went from Vanderbilt University at that time to help start the center [00:18:37.466] and partly because it has unique features. [00:18:41.006] Most of the easy vaccines have already been made
for the viruses that we have and the formula, [00:18:49.236] the risk benefit and the cost benefit formula now for vaccines is such that it may not be [00:18:55.386] that industry alone will be able to develop very many more vaccines. [00:18:59.336] And so the unique feature of our program is there is government money, [00:19:06.836] public money for public health in vaccine manufacturing. [00:19:10.976] That has not occurred very often. [00:19:12.826] If it has occurred, it is mostly been in the setting of the military. [00:19:16.456] It is a very mission oriented program, unlike many programs at NIH [00:19:23.046] that are more free flowing, basic research, follow the idea. [00:19:27.846] This is very mission oriented group and self contain means that we cover a broad array [00:19:34.766] of activities all the way from atomic structure of the proteins [00:19:39.376] to clinical trials in a relatively small group. [00:19:44.336] So these are some of the principal investigators of the VRC. [00:19:47.626] We work out of Building 40 on the NIH campus, [00:19:51.426] but now the program also includes what we call the pilot plan, [00:19:55.556] which is a GNP production facility in Frederick about 20 miles north of campus. [00:20:00.406]
It is a state of the art facility that is every bit like you would see at a Merck or a Glaxo. [00:20:09.396] There is a clinic here now in this building. [00:20:13.696] This is the new Building 10, so we can do phase one clinical trials. [00:20:18.156] This is the clinical trials group and we also have a processing cite in Gaithersburg, [00:20:24.256] a few miles away that processes our clinical samples [00:20:27.036] and does good laboratory practice end point analysis. [00:20:32.136] We also can do small animal work and we have a primate colony spread out throughout the world [00:20:38.386] of about 500 Indian (inaudible) that allow us to do the studies we need [00:20:44.046] to do pre-clinically before we get into clinical trials. [00:20:47.586] And because the gates are imposing and the fence around NIH is imposing, [00:20:52.316] we now have a mobile clinic to see if we can reach [00:20:54.706] out beyond the gates to do these clinical trials. [00:21:00.356] And since 9/11 in 2001, our mission has expanded somewhat and I won't say anything [00:21:05.826] about these other programs, but in addition to HIV, we now have a programs [00:21:10.726] or have done programs on Ebola Marburg, smallpox vaccine, alternative smallpox vaccine, [00:21:19.146] West Nile Virus, SARS caronavirus,
and influenza viruses. [00:21:23.836] [00:21:24.846] So the story of HIV vaccine development has been kind of staggered and it has its ups and downs. [00:21:34.766] Pat Thomas has written a book about some of these ups and downs, some of the peaks [00:21:38.646] and valleys that she has witnessed, but there has been a clinical trials program [00:21:44.056] for HIV vaccine evaluation since 1987. [00:21:47.756] Vanderbilt was one of the founding sites and since that time, [00:21:51.586] a number of different vaccine products have been developed and may be [00:21:57.156] as many as 60 different concepts. [00:22:00.296] And but those have only resulted in a small number of efficacy trials [00:22:04.636] where you actually test to see whether a vaccine works or not [00:22:07.266] and the first one was this Vac Gen GP 120, which was based on a purified protein. [00:22:12.906] It was based on the same thing that the Hepatitis B vaccine was based on [00:22:18.026] and the problem is because we weren't inducing antibodies [00:22:23.796] that could neutralize the common virus, it did not work. [00:22:27.226] So that trial ended in 2003. [00:22:30.136] A purified protein can induce antibodies in CD4 T cells, but it cannot CD8 T cells,
[00:22:36.926] the ones that can clear the virus infected cells. [00:22:40.096] And so from that time, even before that time, studies were being done [00:22:46.086] with vectors, vector based vaccine delivery. [00:22:48.446] So this RV 144 is a trial using a canary post vector boosted with this GP 120. [00:22:57.846] It is in 16,000 people in Thailand. [00:23:00.636] They had an interim analysis in 2007 and 8, the trial is continuing and we will hear [00:23:06.586] about the results of that study, I think this year in October. [00:23:11.666] And then there was the Merck studies, where they took an ad nil virus based vaccine [00:23:17.496] and add 5 vector, I will tell you more about that and did something called the step study. [00:23:22.996] That is where the title of my talk came from, because the step study was a good idea. [00:23:30.226] It was testing a very important vector that can induce CD8 T cells that could have a chance [00:23:37.266] of clearing the virus early and it was conducted first in North America and then in people [00:23:45.976] who are adnel virus naive, add 5,0 negative and then extended to add 5 immune people [00:23:53.316] and then it was extended to a sister trial in South Africa called Pambilly (assumed spelling), [00:23:59.416] so these 6,000 people were studied with the Merck vaccine and you see these big red Xs. [00:24:05.676] There was something that happened in this
trial and that was at the interim analysis [00:24:10.996] when they were evaluating this first trial that was primarily in North America, [00:24:15.386] they found that among the vaccinees there was a higher rate [00:24:18.896] of infection then among the placebo recipients. [00:24:21.816] So the vaccine was causing an increased rate of infection at least among some of the sub groups [00:24:28.536] and we will talk about those sub groups later, but the consequence of that was [00:24:32.666] that the Pambilly trial was immediately stopped and this pay 100 trial [00:24:38.546] which we had been planning for the last 7 years, which was slated to start on September 28 [00:24:46.646] of 2007, 10 days after this Merck announcement never started. [00:24:52.306] So this pay 100 study that was going to evaluate a different gene based vector concept did not [00:24:58.536] start, so I will tell you the basis for that vaccine product. [00:25:04.996] I will tell you the differences between it and the Merck product [00:25:08.146] and then I will ask you what you think about starting the 505 study [00:25:12.796] and you can help me decide whether it should go forward. [00:25:16.656] [00:25:17.766] So the VRC vaccine candidate was multi-valient. [00:25:21.866] It included envelope genes from plates A, B and C that covered about 85 percent
[00:25:27.566] of the incident stains in the global epidemic, attempting at least [00:25:31.686] to have broader coverage of a greater number of viruses. [00:25:36.806] And it included multiple genes, not only the gag and paul genes, [00:25:42.176] but the nef gene and these envelope genes. [00:25:45.046] So it included a lot of genes and a lot of plates to cover a lot of viruses [00:25:50.366] and it used two different types of platforms, a DNA vaccine platform to prime the response [00:25:58.636] and an antinal virus based platform to boost the response, the DNA was delivered [00:26:03.616] by this needle free injection system and the boost had a set of matching genes. [00:26:08.336] And so what we knew about that vaccine is that in non-human primates, [00:26:13.676] among the vaccinated animals, you could lower the peak virania relative to the controls [00:26:20.426] and you could lower the early set point virania in animals who had been vaccinated [00:26:26.086] with a similar type of vaccine and challenged with SIV, a simulated immune deficiency virus. [00:26:33.286] We also knew that vaccinated animals had a survival advantage [00:26:37.436] in this very stringent SIV challenge model and so that DNA ad combination had better protection [00:26:46.896] in monkeys then the adnil virus alone product from the Merck studies.
[00:26:51.926] We also know that in this example where compared to the sham or the mock vaccinated animals, [00:27:00.886] animals immunize just with the DNA add (inaudible) gag and paul, [00:27:05.686] which had a relatively small reduction in the set point virania, [00:27:09.756] had a much larger reduction in the semen viral load. [00:27:14.506] So the amount of virus in the mecak (assumed spelling) semen [00:27:19.686] that could be detected was even greater, [00:27:23.356] more reduced in the vaccinees then you would have guessed [00:27:27.276] from just looking at the plasma virus. [00:27:30.756] We also know from early phase one clinical trials that giving either DNA alone [00:27:35.756] or adnil virus alone compared to the combination of DNA and adnil virus [00:27:40.086] that the heterologist (assumed spelling) gene based combination gave a much higher antibody [00:27:44.236] response, more than 100 fold higher antibody response and if you measure T cell responses [00:27:50.416] and this is an ell-(inaudible) essay, but it is a measure [00:27:54.266] of these CD8 T cells that I have been talking about. [00:27:57.466] If you combine the DNA and adnil virus, you can see about a 5 to 7 fold higher response [00:28:04.036] of T cells in the combination than you can
in either of the modalities by themselves. [00:28:10.586] And the response was also qualitatively different. [00:28:13.756] One of the big features of this new center is all the ways we can measure T cell responses [00:28:19.906] and Mario Roater and Rick Kelp there have pioneered this use [00:28:24.736] of poly functional T cell analysis using flow based methods where we can pheno type cells [00:28:32.236] and then define whether they are making these degranulation markers or putting out the things [00:28:37.926] that can kill the target cell or making these various (inaudible) that are a measure [00:28:43.626] of the CD8 T Cell function and we can measure all of these things [00:28:47.316] at the same time on a single cell basis. [00:28:49.866] So there is really a large number of phenol types in these cells, but we condense them [00:28:56.636] down into just how many functions are present and we can ask [00:29:01.806] in the HIV response is it poly functional or relatively oligal functional [00:29:08.446] and what you can see in both CD 4 and CD 8 T cells compared to just adnil virus by itself, [00:29:16.026] the DNA ad combination is much more poly functional. [00:29:19.086] There are many more cells that are making 3, 4, or 5 functions instead of 1 or 2. [00:29:26.906] And so in the DNA ad heterologist prime boost combination, we are seeing more T cell response
[00:29:33.486] and a more functional T cell response. [00:29:37.106] So this product was moved in to phase 2 studies and this was done on three continents [00:29:42.616] and three major regions by three major networks, so we had network partners, the HVTN, [00:29:49.716] which was domestic and also in South Africa, US Military Research Program, [00:29:55.296] the International AIDS Vaccine Initiative, a nonprofit and a military program work together [00:30:01.306] in East Africa with a very diverse group of investigators [00:30:05.336] and we accomplished a 920 person study that we called the Triad [00:30:11.606] and in that I will just show you this one table and bottom line that either at our facility [00:30:18.776] in Gaithersburg, the HVTN labs in Seattle, the IOVI labs in London or the military field sight [00:30:25.696] in Tanzania, if you measured T cell responses in the field in these vaccines in populations [00:30:32.026] at risk, you could see about a 70 to 80 percent response rate, [00:30:36.446] which was considered good at the time. [00:30:40.596] But then on September 18th, our September 18 was worse than September 11th, in some way, [00:30:49.306] but this report from the Merck study showed that there was increased rate [00:30:55.446] of infection among vaccinees compared to placebos and it was even more profound in people [00:31:01.586]
who were prior, previously exposed to adnil virus 5, so ad 5 zero positive people, [00:31:08.706] there was a risk rate, odds ratio of some place of around 3 [00:31:13.976] to 1 vaccinees to placebos getting affected. [00:31:17.586] So the question is first of all what is going on there and second of all is it safe [00:31:23.136] to do any more gene based vaccine studies? [00:31:26.266] So the next analysis broke it down into whether a person's ad 5s were all negative or positive [00:31:34.286] and whether they are circumcised or uncircumcised [00:31:38.126] and what you see here is the greatest risk among vaccinees was among the uncircumcised men [00:31:45.856] and this entire analysis was done in men. [00:31:49.266] So of the 83 infections in that first analysis, 82 of those analysis were in men. [00:31:55.746] This analysis is only evaluating gay men in North America. [00:32:02.376] [00:32:03.456] And so, the odds ratio is highest in uncircumcised whether they are ad 5, 0 positive [00:32:09.846] or not, but there also appeared to be some risk among circumcised men [00:32:15.616] if they were add 5, 0 positive. [00:32:18.796] So the question is if you just focus in on this group of circumcised ad 5 naive individuals [00:32:30.316] where the relative risk of vaccination was less than 1,
[00:32:35.936] could you do a safe vaccine study in that population? [00:32:41.346] The other piece of data that came out of the Merck study was that among people [00:32:45.816] who had a low ad 5 antibody before vaccination, if you looked at their LE spot response compared [00:32:56.656] to the viral load after they were infected, there appeared to be a correlation [00:33:01.686] in those people who are ad 5 naive, ad 5, 0 negative, as opposed to the people who are ad 5, [00:33:08.526] 0 positive prior to vaccination where there was no correlation at all. [00:33:12.136] So the question became was it safe to do a vaccine trial in ad 5, [00:33:17.736] 0 negative circumcised men and ask the question can we identify a T cell measurement [00:33:25.756] that correlates with reduce viral load [00:33:28.096] and at least take another step toward finding an HIV vaccine. [00:33:34.146] So that is one piece of information that you need. [00:33:37.606] Now I am going to compare the VRC vaccine to the Merck vaccine [00:33:42.346] and you can then judge if it is different enough. [00:33:47.226] So the VRC vaccine includes these plasma primes with an adnil virus boost. [00:33:52.226] It is an ad 5 based vector. [00:33:55.036] It has some differences, but the gag paul
included in ours is represented here. [00:34:00.346] In the Merck vector, there was a gag paul naf adnil (assumed spellings) given repeatedly [00:34:05.566] at 0, 1 and 6 months. [00:34:08.116] [00:34:09.156] So the genes differed somewhat, our product included gag and paul and nef, [00:34:16.086] as did the Merck product, but we also included envelope genes, [00:34:21.916] so there was a little bit difference in antigenic content and then this is a nuance [00:34:28.416] to some people, but it may be one of the most important differences in these two vectors. [00:34:34.066] There is different ways of making adnil virus vectors, the Merck vector used the E1 region [00:34:40.076] to put the trans-genes, so the gag and paul and nef were put here, [00:34:45.296] so that when the adnil virus was used to deliver the gene, those genes were expressed [00:34:50.366] out of this site, but that means the rest of the genome backbone [00:34:54.326] for the adnil virus was also making RNA and making adnil virus proteins. [00:35:00.586] In our construct that was made by Gen Vec, not only was the E1 region used [00:35:06.396] for expressing the trans gene, but the E3 region was deleted, partially deleted that is a region [00:35:13.856] that adnil virus uses to modify immune responses. [00:35:16.826] It has analogs to different cemokin
(assumed spelling) receptor genes. [00:35:21.166] It has proteins that will down regulate the MHC molecules and so this contains a lot [00:35:28.086] of immune avoidance genes that was deleted. [00:35:31.016] And importantly, this E4 region was deleted and E4 region has a set of genes [00:35:35.796] that allows the other adnil genes to be expressed and so if you just look [00:35:41.826] at the blots here of the kinds of proteins in adnil virus that are made [00:35:47.036] by either an E1 deleted or E1, E3, E4 deleted vector, what you see is the hexon [00:35:51.536] and the panton based in the fiber that makes up the capsule of the adnil virus [00:35:58.816] or made from the E1 deleted vector, but not made, [00:36:02.576] so there may be a lot more adnil virus proteins being made if you don't believe the E4 regions, [00:36:09.136] so that is the other difference in these vector systems. [00:36:12.856] So in the field studies, we saw that not only in the phase one studies, but in the field studies, [00:36:19.666] six months after the adnil virus boost, you were able to maintain a fairly high level [00:36:24.816] of T cell response to the different envelope A, B and C proteins or peptide pools and the gag, [00:36:34.256] not so much against Paul and nef. [00:36:36.946] But against the envelope and gag proteins, even after six months,
[00:36:40.776] there was a good T cell response. [00:36:42.926] [00:36:43.946] So the question is and this is what we believe and I would like to hear comments [00:36:48.906] from the audience on whether I have made the case to you. [00:36:52.806] That is that we think it is safe to proceed with this type of product, [00:36:56.576] an ad 5 antibody negative circumcised MSN because of the partial protection [00:37:03.506] in SIV challenged monkeys, we think we have a slightly different possibility for efficacy, [00:37:09.896] because there are differences in the antigenic content and the pattern of immune responses [00:37:14.656] with a more balanced CD4 and CD8 and more envelope and gag rather than paul [00:37:19.996] and gag response and because importantly we have the opportunity to identify T cell responses [00:37:26.766] that could correlate with reducing virus load, [00:37:29.736] which were made to take the next step in vaccine development. [00:37:33.226] We think there is a good scientific basis and ethical basis for moving forward. [00:37:38.756] So there is a trial called HVTN 505, it is much smaller than that original pay 100 study. [00:37:46.246] It is designed to study this vaccine in this group that I just described and it would enroll [00:37:54.436] about 1,350 people, half of who would receive this vaccine and half of who would not [00:38:00.216]
and the major end point would be able to see if they could reduce viral load by at least a log [00:38:05.546] in those people that became infected despite being vaccinated. [00:38:11.206] So if we were able to start that study and it has now been submitted to the FDA [00:38:15.316] as of just a few days ago, the crew would again around July and that means that sometime [00:38:24.726] in 2012, we would know if this vaccine was having the affect that we thought it was. [00:38:31.916] So I am going to stop there for just a moment and I would like to take a few questions [00:38:36.896] and I want to go on to finish what alternative strategies there may be. [00:38:42.586] So if anybody has a question or would like to make a comment here, let me hear it? [00:38:47.756] >> The Merck study was done just in (inaudible) is that correct and if so, what? [00:38:54.876] >> Well the Merck study was done initially in people who are ad 5, 0 negative in 1,500 [00:39:03.726] and then it was extended to ad 5, 0 positives in North America and the Caribbean. [00:39:09.376] It turns out that about 1,200 of those 3,000 were women, 1,800 were men, [00:39:17.456] but almost all of the infections were in men. [00:39:23.336] It says a couple of things. [00:39:24.826] One it says that we aren't very good [00:39:27.386] at identifying high-risk cohorts of women in the United States.
[00:39:31.926] It also probably says that women follow directions better than men. [00:39:37.476] You can interpret it either way. [00:39:40.666] [00:39:43.146] >> In terms of phase twos for something like this, how much does putting [00:39:49.506] on the trial change behavior, I mean. [00:39:56.946] >> Well when you go into start preparing sites for a vaccine trial, [00:40:00.696] the question is how much does preparation change the dynamic of where you can do the trial. [00:40:06.946] So when you start preparing sites like this for vaccine work, it often takes years [00:40:13.236] of preparation of cohort development, education, testing and treatment, [00:40:20.436] exercises and so generally if you go into a place with a zero incidence of 3 [00:40:26.496] to 4 percent a year, after a year or two that incidence will be halved. [00:40:32.076] It will go down to 1 to 1 1/2 percent per year. [00:40:36.536] So in general, it will go down about 50 percent. [00:40:41.956] It is hard to get it to go below 50 percent with just educational intervention, [00:40:47.456] but it does start making a big difference in the number of infections [00:40:51.546] that you might expect from a given cohort. [00:40:56.796] >> Bernie, you didn't make it completely clear in my mind, are you testing them
[00:41:04.596] or us that you have refined it and (inaudible) more at this time (inaudible) [00:41:13.986] and what is your deadline going to be, failures do you figure okay no more. [00:41:26.026] >> So, the question is where are we going to do the trial, I think. [00:41:31.666] The trial as it is planned right now, originally it was going to be planned in those same reasons [00:41:37.696] where we did the phase 2, but because of the zero prevalence of ad 5 is so high, [00:41:45.826] especially in Eastern Africa, it is about 95 percent, recruiting a population of ad 5, [00:41:52.216] 0 negative people there was untenable and because [00:41:56.836] of the issues involving safety the trial is going to be done in North America where at least [00:42:05.456] to ad 0 prevalence range is at 50 percent instead of 95 percent, [00:42:10.656] so we at least have a chance of enrolling people. [00:42:14.036] So this trial would be planned for North American MSM, men having sex with men, ad 5, [00:42:21.006] 0 negative circumcised men, but the subgroup in the Merck study [00:42:24.976] that actually may have had a benefit from the vaccine [00:42:29.106] at least had a lower odds ratio for infection with the vaccine. [00:42:35.886] The second question is how many times will we fail
[00:42:39.876] with an HIV vaccine approach before we stop testing and developing HIV vaccines. [00:42:48.136] Well if I tell you that there is 7,000 new infections every day with HIV, [00:42:54.936] do you think we should stop trying? [00:43:01.016] >> Oh no (inaudible). [00:43:03.086] >> So our goal is to never stop trying and either we are going to find a vaccine [00:43:11.796] or we are going to change the dynamic of HIV in the world by trying to develop a vaccine [00:43:17.576] and the question is you know what is it going to take to develop a vaccine [00:43:24.896] and I am going give you a few additional slides about some of the new approaches [00:43:28.976] that are being taking and some of the technology that is being applied to this problem [00:43:32.496] and hopefully to get us to the point that we can have a more effective AIDS vaccine, [00:43:37.806] but you know if you look at the malaria field, there have been at least 20 [00:43:42.376] to 30 failed efficacy trials for malaria vaccines. [00:43:46.306] If you look at the development process of almost any other vaccine product, [00:43:50.956] you have to go through a lot of failure to ever achieve something that is working. [00:43:55.406] We are still working to improve the influenza vaccine, something that is already licensed. [00:44:00.126] So I think that in vaccine
development in general, [00:44:04.826] there is a lot of failure before success typically. [00:44:10.536] [00:44:14.166] So one of the problems for achieving the kind of breadth we need, not only the breadth [00:44:22.166] of response in an individual, but the breadth and response in the population to cover all [00:44:27.056] of the possible incoming HIV viruses is being addressed and an informatics approach [00:44:34.396] and Betty Corber (assumed spelling) at Los Alamos is a brilliant mathematician [00:44:38.926] who also is a trained immunologist and she has brought a lot [00:44:43.596] of innovation to HIV vaccine concepts. [00:44:48.376] So one of the things she has done is using bioinformatics, she takes sequences [00:44:54.666] from a large population of individuals. [00:44:59.006] So for instance, all these different lines might represent a population, [00:45:05.496] well these would be the different viruses within a population and then she puts it [00:45:12.036] through her computer algorithm and asks if I start recombining these sequences [00:45:18.596] at natural recombination break sites, because HIV does a lot of recombination [00:45:24.096] and I keep remaking recombinations of viruses and then I ask [00:45:30.276] within those new virus recombinants, how many of the T cell epitomes that have been mapped
[00:45:36.476] within these viruses have been retained and can I achieve a virus sequence [00:45:41.366] that is relatively natural with the normal break points, but that has achieved a higher level [00:45:48.866] of epitome coverage for the different virus possibilities. [00:45:53.026] And what she has found by doing that, she can find winning sequences from each [00:46:01.116] of these recombination experiences and then by using a combination of these, [00:46:09.116] in silica recombined sequences, she can achieve about a 20 to 30 percent higher level [00:46:16.676] of coverage with new epitomes above any given single natural isolate or even a combination [00:46:24.306] of natural isolates and that is now proving to be true in animal experiences. [00:46:28.526] So if you use a cocktail of two or three mosaics or four mosaics compared to a cocktail [00:46:35.426] of three natural isolate sequences, you can achieve a much broader range of response [00:46:41.176] and so instead of having the three or four epitope response [00:46:45.126] in a normal setting you might achieve in some of the monkey studies, [00:46:50.176] they have gotten up to 12 to 20 epitope responses. [00:46:53.676] So the thought is especially in T cells, if you can achieve multiple responses [00:46:57.676] to multiple epitopes, it will be much harder for that virus to escape, just like three drugs is
[00:47:04.086] when we really started making a big impact on HIV instead of just single treatment [00:47:10.126] where the virus can serially escape. [00:47:12.856] So this new concept of mosaic inserts is now being combined with a whole variety [00:47:18.666] of new vector choices which are being developed, not as DNA and ad 5, [00:47:25.356] but there is a whole variety of gene based vectors that are being used and combined [00:47:30.306] in different ways using these new insert designs to see if we can really maximize the breadth [00:47:36.256] and the magnitude of the T cell response. [00:47:39.036] [00:47:40.306] But the real problem is antibodies, so I am going to end with a brief series of slides [00:47:46.746] on the antibody problem and most vaccines have worked because we introduce an antibody [00:47:52.076] and it turns out for various reasons, because this protein, this GP 160 protein on the surface [00:48:00.536] of HIV is so highly cligoscualted, it is hard for antibodies [00:48:05.546] to reach the most vulnerable sites. [00:48:07.176] It is very flexible and so there is a lot of different forms that it takes before it locks [00:48:13.756] into the sector making it hard for an antibody to ever lock in on a single confirmation [00:48:20.256] and the sites that are most vulnerable are hidden in these places. [00:48:24.896]
If you were looking at the top of this molecule even in a groove [00:48:29.196] that requires an antibody coming in at just the right angle, [00:48:33.236] just the right specificity to neutralize. [00:48:36.396] So over all these years, there has only been a handful of antibodies that have been found [00:48:41.796] to broadly neutralize the commonly transmitted strains of virus. [00:48:46.846] Two of them are against this membrane proximal region in the GP 41 [00:48:51.916] that is anchoring the protein to the viral membrane and then two of them are [00:48:58.416] in this GP 120 head, one of them is where the CD4 binding site is for main receptor [00:49:06.826] of the virus, that is the B12 antibody. [00:49:09.346] The other one is 2G12, which recognizes a combination of glocisolation sites [00:49:15.806] that is not particularly well understood. [00:49:18.536] So the question is if you apply structural biology [00:49:21.686] to understanding exactly the atomic structure of these GP 120 molecules in their different forms, [00:49:29.476] can you use structure based vaccine design to find something [00:49:34.726] that might actually work for neutralizing antibodies. [00:49:38.146] So one of the big findings early on using this structure based approach is
[00:49:43.776] that if you compare this core structure over here, which Peter Cong solved in 1998, [00:49:50.186] this is taking off a lot of the GP 120 just looking at the core molecule and asking [00:49:57.136] in the CD4 bound confirmation, bound to its receptor, what is the GP 120 look like [00:50:03.306] and this domain right here, which is called the bridging sheet. [00:50:08.086] This is where the CD4 binds, this is the inner domain and the outer domain. [00:50:13.316] This is the place that binds the co receptor for HIV, the CCR5 or CCR4, [00:50:19.026] so this is one of the early important vaccine targets thinking that we could use [00:50:24.856] that as a target for vaccine development. [00:50:27.576] Well it turns out a few years later when Harrison solved the unbound, unleaded structure, [00:50:34.736] if you look at GP 120 before it is bound to its structure, these two regions that make [00:50:40.246] up the bridging sheet are not even together and so that region doesn't even exists in the virus, [00:50:46.446] before it is already bound to its receptor. [00:50:49.306] So using this kind of structure information, [00:50:52.486] we can have a much better idea of what the targets are for HIV. [00:50:56.886] So making antibodies to the bridging sheet is obviously not an option based on this and [00:51:05.226] but in contrast if you focus not on the inner domain and its changing position,
[00:51:11.406] but the outer domain, the outer domain in both the unliganded [00:51:15.386] and liganded position is very constant, [00:51:18.796] so this region of the GP 120 molecule remains very constant. [00:51:24.566] So Peter and his group at the VRC have used a series of experiments [00:51:31.136] where they co crystallize these antibodies, these broadly neutralizing antibodies the GP 120 [00:51:37.026] or the GP 41 and they determine exactly what the structure of the binding stuff is [00:51:42.836] for neutralization and one of the more important papers was this one [00:51:47.156] where they used the B12 antibody pictured here interacting with the CD 4 binding site here [00:51:53.686] and then they mapped the region of the antibody foot print to the CD 4 foot print to try [00:52:00.306] to really show how the antibody was binding to neutralize the virus. [00:52:05.336] So if you have that information, what do you do with it? [00:52:10.106] So the different approaches now that are being taken with the proteins, [00:52:14.986] based on this structural information is the following. [00:52:18.266] First of all one of the problems with HIV is this reason here [00:52:23.206] where CD 4 binds is somewhat blocked by the other primers and these regions in here,