NIH CLINICAL CENTER GRAND ROUNDS
Episode 2010-01
Time: 1:01:48
Recorded January 6, 2010

Dr. Robert Martensen, director of the NIH Office of History and Museum, will address "Human Subjects Research and the Internet Era." Dr. Robert Kreitman, chief of the clinical immunotherapy section in NCI's Laboratory of Molecular Biology, will present "Updates on Therapies for Hairy Cell Leukemia."

ANNOUNCER: Discussing Outstanding Science of the Past, Present and Future - this is NIH Clinical Center Grand Rounds.

(Music establishes, goes under VO)

ANNOUNCER: Greetings and welcome to NIH Clinical Center Grand Rounds, recorded January 6, 2010. Our first speaker, who is a physician and an historian, will address "Human Subjects Research and the Internet Era." Dr. Robert Martensen is director of the NIH Museum and the Office of History. He also is a lecturer in the Department of Global Health and Social Medicine at Harvard Medical School.

Dr. Martensen is a graduate of Harvard and earned his MD degree at Dartmouth Medical School. He interned and completed a fellowship in emergency medicine at the University of California, San Francisco, where he also earned a PhD in the history of health sciences.

Dr. Martensen has published extensively on the history of medicine and science and on bioethics. During the mid-1990s, he published more than 40 short articles in JAMA that placed medical developments of the late 1800s in a broad historical context. His 2004 book, The Brain Takes Shape: An Early History, explores how and why interest in the human body shifted during the Scientific Revolution from the heart to the brain. Another book—A Life Worth Living: A Doctor's Reflections on Illness in a High-Tech Era—was published in 2008. It explores changes in American health care during the past 30 years. In 2009, the American College of Surgeons published his co-edited volume, Surgical Palliative Care: A Resident's Guide. Currently, he is working on a history of translational research and planning an NIH conference on that topic with NCRR director, Barbara Alving, and others.

Before coming to NIH in 2007, Dr. Martensen was professor and chair of the Department of Humanities at Brody School of Medicine in North Carolina. From 2002-2006 he was the James A. Knight Chair of Humanities and Ethics in Medicine and professor of surgery at Tulane. Dr. Martensen's professional memberships include the American College of Surgeons, the History of Science Society, and the American Association for the History of Medicine.

Our next speaker will address "Updates on Therapies for Hairy Cell Leukemia." Presenting is Dr. Robert Kreitman, chief of the clinical immunology section in NCI's Laboratory of Molecular Biology.

Dr. Kreitman earned a BS degree at Kent State University and his MD degree at the Ohio State University College of Medcine. He completed a residency in internal medicine at Duke University Medical Center and a fellowship in medical oncology at NCI. He has been in his current position with NCI since 2000.

The primary focus of his research is the therapy of hematologic malignancies with recombinant toxins and the study of the interaction of toxins with the patient's malignant and normal tissues. A second—and partially overlapping—focus is in the development of new treatment paradigms for hairy cell leukemia both early and multiply relapsed.

Dr. Kreitman's memberships include the American College of Physicians, the Association for Cancer Research, and the American Society of Clinical Oncology.

He is on the editorial boards for the Journal of Clinical Pharmacology, Molecular and Cellular Pharmacology, Oncology Reports, and Current Molecular Medicine.

We begin with Dr. Martensen.

MARTENSEN: In our time this morning I would like to talk about human subject protection program on the Internet from a few perspectives. We could look at it for example from the point of view of the human subject, point of view of the researcher, the trial sponsor and from the point of view of program administrators. But we'll be looking at it from a few perspectives and the objectives of my talk are to give you a sense how IRBs actually work which is different than the kind of conventional wisdom on how they work, I would argue. How to improve their performance, therefore, and the relationship of those two subjects to the importance of trust relationships between researchers and IRB administrators as well as between IRB trial sponsors and the public. In short, in all aspects of clinical research.

So I have four parts, I'll be spending most of the time on part one. IRBs and researchers. And then move into the other area, sponsor communication, what it means to be a professional and trust relationships today, in the Internet era and some challenges and opportunities.

Let's turn first to IRBs and researchers. When I talk about an IRB I'm considering it as an entity in itself and as part of a larger picture which are human research protection programs. First of all I think it's important to note the difference between early IRBs, that is those of the 1960s and '70s and today. At the beginning when IRBs became a routine feature of clinical research, the idea was locality was just a great thing because institutions varied. When the first IRB which wasn't called that, was set up in the clinical center in the early 1950s, locality was viewed to be the key. Has what was a virtue now become an Achilles heel? Because today in the area of multi-center trials observers criticize IRBs for not agreeing with one another when evaluating the same protocol. This critique happens at a couple of different levels. First of all, it's been put forward as a scientific issue. In other words, locality translates as inconsistency. This was based on a study done in Baltimore, a single protocol was submitted to multiple IRBs in the Baltimore area and according to the report inconsistencies in these review raise questions as to the validity and efficiency of the IRB process. And it's a sense in which any measuring instrument measure what is it's intended to measure, well if you get different decisions on the same object, that would be a sign of inconsistency. So it's seen as a false.

What happens now with the Internet, how does the Internet amplify and change what locality means? First of all, as we all know, if we just go shopping online and you getting services that aggregate different prices for the same object, the Internet easily exposes variation of all kinds. In this context variation between one deliberative body and another. And if one looks at what trial lawyers do for example, on the plaintiff's side they shop jurisdictions based on variations in evaluating similar kinds of complaints. So local variations have become obvious in ways they have never been before, easily obvious. Obvious to almost anyone professional or lay. And secondly, I would argue that this new transparency raises a basic notion of fairness, to be fair most people would say common sense, like should be treated alike by deliberative bodies, particularly those operating in the public sphere.

What is the conventional wisdom? When you look at authors of IRB studies are typically researchers, many of whom are physicians, some of whom are not or traditional ethicists, they conclude variations some from two sources. Either dubious application of federal regulations, which indicates lack of knowledge, or hasty judgments made by overburdened board members and administrators. Lack of resources.

So it's not surprising when one looks at their remedies, what are the remedies for this problem of variation and locality and inconsistency? The remedies fall in two broad categories. First, it's an educational model, more training and more staff. And more money and more oversight. More regulatory oversight. Now, based on some work by sociologists and anthropologists who have done field studies of how IRBs actually work by sitting in lots of IRB meetings, and interviewing lots of people involved with them, the standard account that I just went through maybe incorrect or certainly not wholly correct. When one looks at the interview aggregates from IRB chairs across the country, it suggests that the difference, the variation, the locality from one board to the next are a product how boards deliberate, not of board's ignorance. In other words, not of mistake in judgments. Because the way boards operate is very dependent on the stream of local precedents that they have experienced.

What are local precedents? They are decisions board members use to guide evaluations of subsequent protocols. By drawing on them, members tend to renew protocols as permutations of studies they have previously debated and settled. So instead of applying from the general to specific, which is the standard account, actually they tend to work from case to case. I think this has important implications as you'll see in a moment.

So a local precedent is a decision process. IRBs in other words may vary not because they're mistaken but because they strive to make locally consistent decisions over time. From that perspective, local precedents tend to be idiosyncratic to each board, but stable intra-board, within a board. What does this mean for the researcher? It means when a local precedent hasn't been established a PI may help shape the solution. This is a challenge because when it's not established the board is going to drag out the process. It's an opportunity in the sense the PI maybe able to set a significant precedent. Once precedents are set and decision making inertia is established future PIs lose influence on the same issue leading to a great deal of frustration.

So what are two of the common variations between IRBs when one looks at the social science studies? First of all, IRBs vary considerably as to the amount of scrutiny a given protocol gets. Whether protocols are expedited depends on how the IRB liters assess risk to protocols. Secondly, in full board reviews IRBs arrive at different decisions requesting approval and the requested modifications differ substantially.

When one is looking at how this might change, make the process preserve human subject protection which is the goal, and also be more efficient, I want to turn to talking about case streams. Thinking in cases requires a regular flow of instances that can be seen as examples of a prior case. So that when case streams do not exist, such as when something has been encountered for the first time, one has a problem -- when case streams do exist, they can be very useful. One thing the Internet does is make it very simple to have model problems and case streams accessible on the Internet to IRB researchers. Suppose IRBs had to access to exemplary protocols and problems as sources of model decisions -- so they could address ethical concerns efficiently. Developing case streams of decision-making precedents available on the Internet to all NIH IRBs might enhance the efficiency of both. What I'm speaking to is how IRBs enhance their role as a trusted source for researchers.

One of the pieces I won't talk about in this talk is several slides that go to the level of frustration many researchers have with IRBs across the United States. I won't refer to those experiences because I assume many people have lived through those experiences, thought perhaps not the NIH.

What is this line of argument I'm advancing imply for reform efforts? Is the way to go more regulation or more coordination? I would argue it isn't to draft more detailed federal or NIH regulations, but to develop case streams as conceptual resources for researchers. For example, if we look at the pre-review phase, how could it be speeded up? And some of this is being adapted or under consideration for adoption here. First of all center protocol service center, which has real people in it, live people one can reach in preparing one's application. Vigorous screening in the PI's home department or lab for all the scientific issues. And protocol navigators such as case stream precedents that somebody can consult for their various specific kind of research. Instead of sending back and forth exchange of draft and edits, adoption of this kind might provide an option that authorizes IRB staff to insert default edits, acceptable precedents, in other words as part of the initial review process.

Another suggestion for expediting is to bring the worth processers and do the edits during initial review. Researchers could choose to decline but those who opt in would receive a review report right after the IRB meeting not ten days later. At the review what can happen? First of all, limiting review areas. If these are adequately reviewed at the departmental level, then a full review shouldn't be concerned with research design. Although when one looks at IRBs nationally a good deal of them spend a lot of time critiquing research design. When it's been pre-reviewed, shouldn't the questions be limited to safety and consent?

Now, what is sponsors to recruits? How are those relationships going? How does communication happen? What I want to suggest here is that we think that what we're saying on a given subject to our patient to a research subjects through clinical trial notice is the primary means by which the subject or patient learns about what we're discussing. That's not really the case. They're absorbing from all over the place. One of the great things about the web is there's all kinds of speech on it from all different sources, it's heteroglosic not to mention television, direct to consumer marketing and so forth.

So how is that communication happen? I'm giving a couple of examples. Here is clinicaltrials.gov, has roughly 85,000 trials on it but there's other sources of clinical trial information, other aggregators out there. This is clinicalconnection.com. Now, they have 105,000 active trials brought into them. How does communication vary between these various kinds of sponsors? They vary considerably by sponsor, by type of sponsor. This was a DHHS study in 2002, only 29 or 110 mentioned potential benefits, these were specific sites and trials. Zero mentioned potential risks.

Misleading speech is common. What I mean by misleading is commercially useful euphemisms. We have new drugs advertised on the Internet for trials. We don't have experimental drugs, we don't have unproven drugs. Now, if we're looking at traditional standards of professional communication we would say this is an experiment, we would say this is unproven. In other words there's a scientific perspective of skepticism ablated on the Internet in favor of a sales perspective of new. This is from a Hasting Center report that looked at studies on depression and diabetes. 38% of the sites didn't appear to provide unbalanced descriptions, 75% provided descriptions of incentives, but half of those failed to mention risks, length of study, none use the term risk and only one use the term side effects. Basic criteria are often omitted. Study length not reported. Most of those that didn't report fully had for profit sponsors, didn't list number of visits, so forth. So in general, the language is on the Internet is weighted towards encouraging research participation. Where do people find out about them, this is from Craigslist. In Baltimore. One can earn $1,500 to partake in a paid study. Do you learn anything else about it other than it's in Baltimore or even what it is? No. But it's a great header on Craigslist. This is San Diego Craigslist. $3 signs, compensation possible. For profit sponsors according to the Hastings report tend to be more misleading. Here is one that's rather slick and quite beautiful, this is on Alzheimer's. This is also on the web from yesterday. Now, this one can go into learn more under various headings. What one can't learn by looking at this is who the sponsor is. It doesn't tell you. You have to track separately via Google searches that sponsor as Wyeth. So what is at stake? What am I talking about? Trust at this point trust between the public and the research community. The funding of sources maybe important for participants to be aware of because misleading speech is common in commercial sponsorships so it speaks to the integrity of information and providing balance. This is the most balanced one that Todd could find on Craigslist yesterday. This is a prostate cancer clinical trial from east village in New York, a neighborhood in New York City. But again, it doesn't really discuss risk other than mentioning treatment as radiation free and has fewer side effects than other cancer treatments. Directory listings are a way that commercial sponsors can bypass IRBs on a director and therefore limit the amount of information they provide on the web. So it is an example how difficult it can be to persuade researchers from not selling participation.

So let me turn to what I think is the larger issue which goes to professional authority and social contract. We tend to think that medicine and the research community of which it's a part and which is a part of it has a rather stable and strong social contract but that's not the case. It's only had a strong social contract in the United States since around 1900s. What do I mean by that? We expect physicians in the research community routinely to provide sound ethical judgments in the face of uncertainty. But ethical principles have changed. In 1950 physicians were expected according to the AMA code of ethics not to be sold by physicians directly, they should be paid primarily for professional services. If we look at an update of the AMA code of principles of ethics it's revised periodically. We find the only advice to physicians is to avoid fraud and deception in their business practices. In short, ethical norms have shifted in the last 30 to 40 years, we live in a world in which commercial interests diffuse all aspects of healthcare whether officially non-profit or not.

What does this mean in the world of the Internet? Nothing like the Internet has occurred in scale since the invention of mass printing. The person on the left is Gutenberg. PubMed we know about. Then in inexpensive texts of all kinds and growing literacy led to questioning of established hierarchies and religion, politics and medicine. Medical licensing disappeared for several hundred years by the way.

We're experiencing a social transformation as profound now in terms of crisis of authority and knowledge. What are some challenges and opportunities? First of all there are the new realities. Private interests and governments cherish secrets. The Internet promotes transparency. This can be a real problem in terms of locality and variation between IRBs, it's also an opportunity to use the Internet as a resource to gain some standardization. Disparate individuals can organize themselves easily.

I think the most poignant example to me in this institution is hearing Dr. Fauci talk about his initial attitude towards AIDS activists in the late '80s and early '90s. Picketing. He thought this was a nightmare. Some of them have become his friends and colleagues and he's integrated their research perspectives into AIDS research. Breast cancer activists would be another. The point is the Internet allows easy aggregation of dissidents of all kinds. This provides real problems for clinical trials that are trying to have a control and a treatment group because the treatment groups can identify themselves on the Internet, figure out who is getting what, and derail the scientific integrity of the trial. So I think it will lead to substantial differences in research design going forward. Of course authority of all kinds is questioned or supported.

What are some challenges and opportunities? Learned knowledge is widely available. There's no professional monopolies. Just as the priest lost control of the Bible 500 years ago. Yet medical literacy remains problematic. The problem is it runs across ethnic groups, formal education lines and socioeconomic status. People with college degrees can also be medically illiterate but not perceived as such. It's a huge problem and underrated in clinical encounter. Corrupted speech is common. Does NIH with multi-center problems insist on balanced presentations? Does it know if they're occurring? All outreach efforts including directory listings possibly could receive perspective reviews and IRBs, it's a loop hole at the moment. I think I'll stop there.

Thank you very much.

QUESTION: We're undergoing transformation at the NIH and protocol development and review. I think the whole issue of local versus non-local IRBs has been discussed extensively and I think the general consensus if there is one here, is there is some value to local IRBs in terms of both investing responsibility institutionally in the process versus for example, a commercial IRB. And in understanding the strengths and weaknesses of the investigators which sometimes is a value. Do you have any thoughts about that?

MARTENSEN: I think that by volume, the largest volume now of IRBs are private IRBs, commercial IRBs. And their bread and butter are what in street language are me too drug studies. And here we have a lot of first in use studies. So when I have been asked for my thoughts I'm what the NIH might do in that area, I recommended going within and not commercializing. But what's still striking here is there's quite a bit of variation between the NIH IRBs.

QUESTION/COMMENT: I'm sorry, I missed the first part of your talk so I missed some of your presentation of the IRB piece. But having been involved in IRBs for a long time I would say that it's very important that PIs be a part of the solution of the ethical and human subject protection dimensions of their research. That's in a sense the NIH has good situation in that because we don't review 100 new protocols at every meeting, we have 11 IRBs, we do have the ability to interact with PIs better but it's still could be better and especially with new research issues which aren't that common actually. I remember when Michael Blaze and French Anderson came with the first gene transfer study. That was something quite new. But most of the things and the notion of case based is the ethical principles don't change, their application and deliberation about them to individual cases continues to be very important. And ideally when the PI should be an expert in the human subject protection dimensions of his or her research because that helps an IRB immensely, if an investigator isn't informed about the issues related to informed consent and cognitively impaired subjects. The IRB is left to sort of salvage the details of how that's done, that's not a good way to protect human subjects. The investigator needs to be an expert and see the IRB as a somewhat neutral contributor in the sense that the IRB doesn't have an investment in the research that the PI has. So I think the idea of the IRBs are sort of always the problem. It really ought to be a more deliberative process. I mean, we do the best we can here and it works probably better here than other places -- and I don't know how these PIs in private practice can quite approach that dimension in their research. They're busy, have things to do, they send their protocol to commercial IRB, that's a much different model. And problematic in many ways.

QUESTION: I'm Dan Rosenblum from NCRR, I work with the CTSA specifically looking at ways IRBs can be more efficient. One thing our program has been emphasizing is metrics. Because without those, you don't have any idea whether your interventions actually have benefited the process. And also what part of the process actually constitutes the hurdle or the delay of the challenge. I wonder with all the suggestions you have made about how the process might be improved, if you have any plan to study them comparatively or to look at what metrics might be influenced, say, by using the case stream.

ANSWER: I personally don't. No. And it's a great research subject. But it's not what I'm working on at the moment.

KREITMAN: Okay. So we're going to do a quick 25 minute update of therapies for hairy cell leukemia. And our objectives are to review the standard therapies to discuss the current use of recombinant immunotoxins that we developed here at NIH. And to talk about some new trials of other agents for hairy cell. I need to disclose that we're going to talk about the unapproved use of the immunotoxins and also Rituximab. I'll told since the government own our patents I don't have to talk about that.

Leukemic reticula endotheliosis, later hairy cell leukemia was discussed by Bertha Bronkly who I trained with at Ohio State University which she described in 1958. It's a constellation of pancytopenia, splenomegaly histosites in the bone marrow with regular cytoplasmic outline. These were shown to be cytoplasmic projection, not really hairs obviously. And there's a fried egg appearance in the bone marrow due to abundant cytoplasm. These are B cells and they are strong for B cell markers and they also express CD 103, CD 11C and CD25. It comprises 2% of all leukemia's. And about 900 cases per year but the prevalence of this disease is probably about 15 to 20 fold higher. And we'll see why in a few minutes.

There's also a poor prognosis variant called HCLV comprising 10 to 20% of the patients that have more severe spleen enlargement, more frequent lymph nodes, less cytopenias, higher lymphocytosis. They have absence of CD25 and they can be absent for CD103. Their response most importantly to analogs is very poor.

So the World Health Organization currently lists these two diseases separately. However, Dr. Roanes in my lab has recently reported, the presence of a poor prognosis variant called VH-434, named for the immunoglobulin rearrangement expressed by the hairy cells, and that also has poor prognosis. It has features of classic shown in red and variant shown in green. It expresses an unmutated immunoglobulin rearrangement in 16 out of the 17, or 94% of cases, and it presents with lymphocytosis like the variant and cytopenia like the classic so it sort of has the worst of both worlds. And it has poor response to initial cladimine median progression free survival after cladimine is 5 versus 22 months, and the overall survival after diagnosis is nine versus more than 26 years.

So I want to back up and talk about the historical treatments for hairy cell and work forward. So steroids, single and multi-agent chemotherapy did little to improve the natural history which gives about a median four year survival in untreated patients. And splenectomy adds a couple of years to that. But alpha interferon described in a journal in 1984 was the first systemic value of value in hairy cell with complete remissions in a small percentage of patients, partial responses in about half, but these responses are not durable and go away after the drug is stopped. However deoxycoformycin published in Blood in 1986 and the New England journal in 1987 was a major advance systemically, and this is one of the two purine analogs with high complete remission rates in the vast majority of patients and even at eight years most of the patients are still in complete remission. And in this randomized trial done between Pentostatin and interferon, this is a first and only randomized trial done in the United States comparing agents, in this disease, there's a huge difference in complete remission rate with Pentostatin far better than interferon. You can see a major difference in relapse-free survival as well. However, because of a high complete remission rate in patients crossing over to Pentostatin from interferon, after interferon fails we see no difference in survival in this trial. But Pentostatin is not the preferred drug in hairy cell leukemia, it's Cladribine the other purine analog. They work by similar but not identical mechanisms. So Pentostatin is a transition state analog between Adenosine and Inosine so it's a potent inhibitor of Adenosine Deaminase. Cladiribine as it's phosphorylated to two chloro ATP inhibits ribonucleotide reductase and DNA polymerase alpha. Because of enzyme peculiarities in hairy cells versus normal cells, these agents are markedly selective for hairy cells. Now Cladribine was published in New England journal in 1990 to give high remission rate and durability of response similar to what is seen with Pentostatin but preferred because it's selective after a single 5 to 7 day course of treatment. However, there is no evidence it can eradicate hairy cell. Even after 15 years follow up, the relapse rates are fairly constant.

So these patients accumulate over the years being resistant to purine analogs and other chemotherapies, so we treated these patients with our anti-CD 22 recombinant immunotoxin BL-22 and published in the New England journal in 2001, also a high complete complete remission rate, but in this poor prognosis group.

Before talking more about our immunotoxins, I want to mention that Retuximab is also effective in this disease as published in Blood in 2003 in this single institution trial 13% of patients had complete remission. However, 8 to 12 doses of Rituximab maybe better than the four used here, and more importantly, Retuximab combined with purine analogs may offer high complete remission rates. And this caused us to wonder whether if you added Rituximab to Cladribine up front at the early part of the disease could you eliminate those few malignant cells that's escape treatment with Cladribine and cure the disease?

We initiated a randomized clinical trial here at NIH and this randomizes patients between initial Rituximab as shown by 8 weekly doses in orange, and versus delayed. And the Cladribine is shown in green. We're treating patients on this trial who have had one or zero prior courses of Clardribine. Our objectives are to see if Rituximab can increase the complete remission rate at six months without minimal residual disease. It's a higher level of complete remission because they had to be negative by flow cytometry and immunochemistry and also PCR. We also want to see if the blood MRD-free survival is longer after simultaneous compared to delayed Rituximab.

There's a reason to speculate that delayed Rituximab might bring a better long term outcome. I am not going to talk about this further except to show we enrolled 17 patients so far in nine months and of the 13 evaluatable patients our overall response rate is 100%. 85% complete remission rate. And 63% of patients are MRD-free after Rituximab and 0% without Rituximab. However, results at one month doesn't predict results at six months and most importantly follow-up well past six months is needed to determine long-term benefit of adding Rituximab and whether this replaces Cladribine alone as standard treatment for first and second line in this disease.

So I'm going to leave monoclonal antibodies for a bit. As you know, these kill cells by immune approaches and by apoptosis and talk about immunotoxins which kills cells directly by inhibition of protein synthesis and induction of apoptosis. We use a special case of immunotoxins called recombinant immunotoxins where we're just using the variable domain of the monoclonal antibody.

In this case I show the anti-tac monoclonal antibody to the IL-2 receptor alpha or CD-25 fragment. The variable domains are joined by a linker and connected to the truncated form of pseudomonas toxin that doesn't contain the binding domain otherwise binding to normal cells. This molecule kills cells by binding to CD 25 on the cell surface, going inside through a coded pit, unfolding at low PH, undergoing proteolytic processing and hitching a ride on a reverse secretory pathway called the KDL receptor to get it from the transreticular golgi to the endoplasmic reticulum, where it can translocate to the cytosol, and once there we believe one molecule is enough to ADP ribosolate elongation factor 2 and cause cell death.

This is a typical response we see in hairy cell leukemia with immunotoxin. This patient had a malignant count of about 500 cells per microliter in green, prior to treatment. And this reduces more than 90% by day 3. This is the effect of the first dose. And more than 99% at one week. This patient got two cycles as shown here by these inverted triangles. And the normal counts show an absolute granulosite count of 300, improving to over 4,000. And a platelet count of 40 improving to over 200. The hemoglobin was supported by red cell transfusions prior to treatment. This patient has not required any red cell transfusion since 1998 when we treated him. How far, however he did require more treatment with BL-22 after relapsing from LMB-2.

And I want to shift and talk about BL-22 as you can see, similar structure as LNB-2 except there's a disulfide bond that is made possible by cystine mutations in the framework regions that hold the FV together. It targets CD22, so CD25 is expressed by 80% of hairy cells versus 100% of hairy cells expressing CD22. So CD 22 immunotoxins would be our preferred agent for targeting hairy cell rather than CD25. And this summarizes our phase 1 and 2 experience with BL-22. We saw 19 complete remission, 6 partial responses, for an overall response rate of 81%. And 13% of our hairy cell patients had a completely reversible hemolytic uremic syndrome during retreatment so HUS is a clotting disorder in the kidneys that leads to anemia, thrombo cytopenia and decreased kidney function but fortunately this resolves within a week or two of treatment in all of our hairy cell patients. But we wanted to avoid this in phase 2 so we had selective retreatment.

We found that with just one cycle of BL-22, we could induce complete remission in a quarter of the patients. And in those patients that we had to retreat, 56%, only those patients who did not have at least a hematologic remission defined by improvement to these parameters of normal cells, we were able to improve our overall response to a complete remission of 47% overall response rate at 72%. So in comparing this -- the phase 1 and 2 experience with this lower average cycles per patient, we saw a slightly lower CR in overall response rate, but the dose-limiting toxicity from HUS fell by more than half and immunogenicity rate fell by less than a third.

So BL-22 response was dependent on spleen status in that patients with spleenomegaly, in spleens less than 200-millimeters had higher remission and overall response rate compared to patients with larger spleens or post splenectomy. We believe a large spleen may inhibit BL-22 tumor penetration and that splenectomy may increase nodal and marrow infiltration of these cells, and also causing a tumor penetration problem. On the other hand it could be that a larger absence spleen is associated with more advanced disease. Either way, we believe that BL-22 could be considered earlier in the experimental paradigm for treating this disease.

And we'd like to mention that we have seen good responses coming in patients with massive spleenomegaly, a patient with 250-millimeter spleen who after six cycles have complete remission. And to this date five years later remains in complete remission. So this shows our long-term outcome in all of our patients with BL-22.

We have not reached the median disease-free survival on phase 2 after a median follow-up of nearly four years. The median disease free survival on phase 1 is about three years. And as shown in these vertical bars, patients still in complete remission, some of them still have no evidence of minimal residual disease by any test that we can look at.

So we'd like to know in some of these patients have we eradicated the disease. So to do this we needed a more sensitive test than what's available. This is the available PCR test where you just use consensus primers that would bind to the expressed immunoglobulin rearrangement which is specific in each patient with hairy cell, in monoclonal for all hairy cells in that particular patient. So you would tend to see a ladder and no monoclonal peak if you had a large number of normal B cells. And so you can get better sensitivity with flow cytometry, this is reported in collaboration with Mary Alice's group than with PCR.

But Dr. Roans in my lab was able to clone and sequence these immunoglobulin rearrangements, designed clonogenic or sequence specific primers and a probe, and then do a real time quantitative PCR using the sequence-specific agents. And we can get a sensitivity of one hairy cell out of a million normal cells. This shows you might use -- how you might use this technology. This is a patient who got seven cycles of BL-22 shown by these blue triangles. And this patient had disease in the bone marrow shown by DD, prior to treatment and had a complete remission, in other words negative bone marrow after one cycle but the flow cytometry shown in green was still positive. It became negative after the second cycle but the RQ PCR results stayed positive and normalized only after seven cycles. This patient continues more than five years later with no evidence of minimal residual disease. This patient on the other hand required two cycles for resolution of disease in the bone marrow and flow cytometry but never resolved the RQ PCR result and he later became MRD positive but still continues in a technical complete remission. So we conclude that RQ PCR is the more sensitive detection method for MRD and hairy cell and maybe useful in the future to gauge the number of cycles to treat with in other words to possibly eradicate the disease.

This is something you can't do with purine analogs because purine analogs just one course is enough to decomplete the CD4 t-cell population for a median of four years. We looked at the CD4 counts in our patients as well as T-cells repertoire and CD8 counts. We found improvements rather than decreases with BL-22 treatment. This was not too surprising because these cells are afterall CD 22 negative.

What about normal B cells? We found using PCR of the CDR-3 domain and spectra typing by gel electrophoreses, also in studies done by Dr. Roans in my lab, improvements in this B cell repertoire after 7 to 10 cycles of BL-22. So we believe that we don't see normal B cell depletion as you would see with Retuximab which depletes B cells for many months after the last dose. Possibly due to the short half life of BL-22.

So we conclude since BL-22 doesn't cause cumulative B or t-cell depletion, it might be useful in multiple cycles to eradicate the disease in some patients. So to better target chronic lymphositic leukemia which doesn't have as good results as hairy cell, we in collaboration with ARA have tested a new molecule HA-22, that has mutations made in ARA's lab, within the CDR-3 domain of the heavy chain. This resulted in a 15 fold improvement in binding affinity, which translates in these matched patient samples tested in my lab, with a median 8 fold improvement. This agent has been tested at the NIH and other centers, in CLL hairy cell and non-Hodgkin's lymphoma in distinct separate trials. And so far the hairy cell trials spurred this furthest along and we have a complete remission rate of 43%, overall response rate of 79 patients in all 28 patients, and in those patients who got more than the lowest dose level, five, we have a complete remission rate of 48%. We also have not seen dose-limiting hemolytic syndrome, only two gray cases of gray 2, much milder form of HUS.

I want to talk briefly about Bendamustine because it has features of purine analog also shown here in orange but also in blue of Alcolating agents shown by the nitrogen mustard group, and although Bendamustine is not published to be effective in hairy cell, we do have data, there's a patient who was severely pre-treated and very immunosuppressed with platelet transfusion dependence as well as red cell transfusion dependence, neutropenic with a high malignant count in the blood, 800 cells per microliter who responded well to Bendamustine alone and after multiple cycles is free of transfusions of platelets and red cells.

So to see if Bendamustine would have a role in treating hairy cell leukemia -- and I also mention that severe adenopathy that can accompany patients without a spleen, resolved well with Bendamustine. We started a randomized clinical trial of Bendamustine and Retuximab in patients with multiply relapsed hairy cell and for those patients with relapsed progression or no response, they can cross over to one group or the other. So this just summarizes the trials that we have that are open for hairy cell leukemia, in the country and in the world that are specific for hairy cell. These are the immunotoxin trials, the Bendamustne trial I mentioned, and then for early hairy cell the Cladribin/Retuximab trial, all these five are the only ones registered in the United States all done here at the NIH. And this is the only trial I'm aware of, a randomized trial multi-center in Italy with one center in Switzerland comparing IV and subcutaneous Cladribine. In summary, Hairy cell is a highly responsive to but not cured by current analogs Pentostatin and Clardribine. The CD4 variant responds poorly. Targeting CD25 is active in hairy cell but only if they're positive for CD25. BL-22 targeting CD22 and hairy cell achieved high complete remission rates with 13% fortunately reversible HUS. HA-22 the high affinity BL-22 mutant achieved similar remission rates at the upper dose levels without serious toxicity so far.

Although the number of cycles are limited by protocol design, it may be possible to safely deliver enough cycles of immunotoxin as well as other forms of immunotherapy like Retuximab and other antibodies to eradicate hairy cell in some patients.

I want to recognize my collaborators and colleagues, particularly Ira Pastan and his section of the laboratory of molecular biology, I want to recognize my clinical and research sections of my section of the lab. And also the pathology hematology medicine pediatric branches metabolism branch, the mark facility that produced BL-22, medimmune that produced HA-22. The pharmacy and most importantly, the fellows and our nurses. Thank you very much.

QUESTION: Why don't all patients go into remission?

KREITMAN: I mentioned immunogenicity. That's a big problem. Immunogenicity is when patients make antibodies to the toxin. And some of them actually may make some antibodies to the idiotype of the antibody. So we find this less often in immunologic malignancies rather than solid tumors where you get 90% making after one cycle. Maybe a third of the patients make antibodies after a single or two cycles.

And so we're developing ways number one to humanize a toxin but also to immunosuppress patient as little bit more to get them to the level of a CLL patient where they would not likely make antibodies. But for right now, this is what's detracting from the complete remission rate that we have.

I think most importantly. There's a small percentage of patients, maybe 5 to 10% that have a poor response to these immunotoxins. We don't understand why. But it's not due to lack of CD22. That's high in all patients with hairy cell.

ANNOUNCER: You've been listening to NIH Clinical Center Grand Rounds, NIH Clinical Center Grand recorded January 6, 2010. Our first speaker, addressing "Human Subjects Research and the Internet Era.," was Dr. Robert Martensen, director of the NIH Museum and the Office of History. He also is a lecturer in the Department of Global Health and Social Medicine at Harvard Medical School. Our second speaker, addressing "Updates on Therapies for Hairy Cell Leukemia," was Dr. Robert Kreitman, chief of the clinical immunology section in NCI's Laboratory of Molecular Biology. You can see a closed-captioned videocast of this lecture by logging onto http://videocast.nih.gov -- click the "Past Events" link -- or by clicking the "View Videocast" link on the podcast homepage at www.cc.nih.gov/podcast. The NIH CLINICAL CENTER GRAND ROUNDS podcast is a presentation of the NIH Clinical Center, Office of Communications, Patient Recruitment and Public Liaison. For more information about clinical research going on every day at the NIH Clinical Center, log on to http://clinicalcenter.nih.gov. From America's Clinical Research Hospital, this has been NIH CLINICAL CENTER GRAND ROUNDS. In Bethesda, Maryland, I'm Bill Schmalfeldt at the National Institutes of Health, an agency of the United States Department of Health and Human Services.