City of Hope Launches Alpha Clinics – A New Stem Cell Clinic


Cancer patients usually have three different options: surgery, chemotherapy and radiation therapy. None of these options elicits a great deal of confidence. A new study at City of Hope will officially open the Alpha Clinic for Cell Therapy and Innovation. At this center, patients battling cancer and other life-threatening diseases will have another option: stem cell-based therapy.

The Alpha Clinic, which officially opened March 19, is funded by an $8 million, five-year grant from the California Institute for Regenerative Medicine. This grant will also be supplemented by matching funds from City of Hope. The Alpha clinic will combine the uniquely patient-centered care for which City of Hope is well-known with the most innovative, stem cell-based therapies being studied to date. This approach will hopefully revolutionize the treatment of not only cancer, but also AIDS and other life-threatening diseases.

“We are in a new era of cellular therapy,” said John Zaia, M.D., the Aaron D. Miller and Edith Miller Chair in Gene Therapy, chair of the Department of Virology and principal investigator for the stem cell clinic. “The California Institute for Regenerative Medicine recognizes this, and they have been leading the field. Alpha Clinics like ours aim not only to provide research to benefit patients in the future, but also to get these innovative treatments running in real-life clinics to benefit patients now.”

The christening of City of Hope’s Alpha Clinic is the culmination of a decade of planning and visionary thinking. When the state of Californian voted to found the California Institute for Regenerative Medicine, the funds now became available to start the institute. New stem cell therapies are ready for clinical trials, and City of Hope is home to one of three Alpha Clinics in the state. The other two clinics are at the University of California San Diego and a joint clinic by University of California Los Angeles and University of California Irvine.

City of Hope’s first trials will study stem cell-based therapies for leukemia, and the use of neural stem cells to deliver treatments to brain tumors. The first such study will modify a patient’s own immune cells so that they can recognize and fight cancer cells. Cancer researchers hope the modified cells will be able to attack existing cancer cells, and also be able to attack the cancer again should it recur.

Brain cancer patients will also be able to enroll in a study that uses neural stem cells, which have an innate ability to home to tumor cells, as a delivery mechanisms for cancer drugs. Genetically engineered neural stem cells can bring targeted therapies across the blood-brain barrier, and can potentially deliver drugs directly to tumor sites, which eliminates systemic toxicity.

The US Food and Drug Administration (USFDA) has already approved a new HIV trial that will be conducted at the City of Hope Alpha Clinic. This trial will use “molecular scissors” known as zinc finger nucleases to edit the blood cells of HIV patients and remove a specific gene. Without this particular gene, the cells are unable to produce a protein that HIV requires in order to invade cells and replicate. The approach has the potential to eliminate HIV from the body.

“As we move forward with our Alpha Clinic, we will also be defining a new discipline in nursing of cellular therapy,” said Shirley Johnson, R.N., senior vice president, chief nursing and patient services officer at City of Hope. “This clinic is a unique opportunity to provide patients with the most leading-edge treatments while still giving them the compassionate comprehensive care City of Hope patients expect.”

The Alpha Clinic launched officially on March 19. Future trials will include T cell immunotherapy for blood cancer, new brain cancer therapies, treatments for breast cancer metastases and ovarian cancer treatments. Zaia said the clinic also plans to work with City of Hope’s diabetes researchers to introduce treatments for diabetes, exploring both the potential of pancreatic stem cells and preventing the immune system from attacking insulin-producing cells.

Spanish Team Develops Anti-Obesity Treatment in Animal Models


A research team from the Spanish National Cancer Research Center (CNIO) has shown that partial pharmacological inhibition of the PI3K enzyme in obese mice and monkeys reduces body weight and physiological manifestations of metabolic syndrome, specifically diabetes and hepatic steatosis (fatty liver disease), without any signs of side effects or toxicities. They published their work in the journal Cell Metabolism. This collaborative project between the Tumor Suppression Group headed by Manuel Serrano at the CNIO (Madrid, Spain) and the Translational Gerontology Branch headed by Rafael de Cabo at the U.S. National Institute on Aging, National Institutes of Health (NIH, Baltimore, MD, USA), included the participation of the NeurObesity group of CIMUS led by Miguel Lopez at the University of Santiago de Compostela (Santiago de Compostela, Spain).

PI3K (phosphatidylinositol-3-kinase) is the name of an enzyme that regulates the balance between the biosynthesis of cellular components and the burning of nutrients to make energy in cells. Specifically, PI3K promotes cellular growth and biosynthesis, which can lead to the induction of growth and multiplication of cells, and ultimately could lead to cancer.

For this reason, scientists who investigate cancer have has a long-standing interest in designing pharmacological inhibitors of PIK3. CNIO, in fact, has developed its own experimental inhibitor, CNIO-PI3Ki, which is being studied for applications as a cancer treatment in combination with other compounds. As part of the characterization of the PI3K inhibitor and to understand how it affects the balance between the use and storage of nutrients in the body, the Serrano team decided to study the effects of CNIO-PI3Ki on metabolism.

“At this point we have veered away from the original anticancer aspects of these inhibitors. In our previous studies, we had seen that one of the normal physiological functions of the PI3K enzyme is to promote the storage of nutrients. We found this to be of particular interest because it is precisely this type of manipulation, regulation of the balance between storage and use of nutrients, that is sought after in treating obesity,” explains Ana Ortega-Molina, the first author of the study, who is working at the Memorial Sloan-Kettering Cancer Center in New York.

To test the effect of their PI3K inhibitor on metabolism, CNIO scientists administered small doses of the CNIO-PI3Ki inhibitor to obese mice for 5 months while those mice were fed a high-fat diet. During the first 50 days, the obese animals lost 20% of their body weight, at which point their weight stabilized. The treatment was administered for 5 months and during the whole time, these mice maintained a stable weight (20% below the weight of non-treated obese mice), despite continuing feeding with a high-fat diet. They also improved their pathological symptoms of diabetes (high glucose levels in the blood) and hepatic steatosis (fatty liver).

“When it comes to obesity, constant weight loss can be extremely dangerous. The ideal solution is to alter the balance between the use and storage of nutrients, to strike a new balance in which there is greater use and less storage,” explains Elena López-Guadamillas who, in collaboration with Ana Ortega-Molina, carried out most of the experimental work. This study showed that the drug had no side-effects and did not produce irreversible effects on metabolism, which is also desirable for its possible future use as a treatment in humans.

In non-obese animals that were fed a standard diet, the administration of the drug had no effect, which is another indication of its safety. “This shows that the activity of the PI3K enzyme is only relevant when there is an excess of nutrients, that is, a high-calorie or high-fat diet,” adds López-Guadamillas.

CNIO scientists then collaborated with the U.S. National Institutes of Health (NIH) in order to test the CNIO-PI3Ki compound on obese monkeys (macaques).  They used a very low dose to ensure higher safety margins, but even with these very high doses, the daily treatment of these obese animals over a 3-month period reduced the total amount of fatty tissue by 7.5% and improved the symptoms of diabetes.

Obesity is one of the most important risk factors within the spectrum of serious diseases that constitute the metabolic syndrome. Many pharmacological agents have been discovered that lead to weight loss, but these drugs often have unacceptable toxic effects (partly due to the fact that these previous agents act on the brain centers that control appetite). In this respect, CNIO-PI3Ki seems to be the exception, at least in animal models thus far, as no such side-effects have been observed, even after long-term treatments (5 months in mice and 3 months in monkeys).

A series of safety characteristics that have been demonstrated in mice is shown below:
1) Selective: CNIO-PI3Ki only produces weight loss in mice that receive an excess of nutrients and not in mice that eat a normal balanced diet. This shows that PI3K plays an important role in the storage of nutrients when food intake is excessive, but is not so important under a normal diet.
2) Weight loss in the mice is due exclusively to loss of fatty tissue; no losses occur in other tissues such as liver, muscle or bone.
3) It does not affect the brain: CNIO-PI3Ki does not cross the blood-brain barrier.
4) It does not affect the hypothalamus: The hypothalamus is a specialized structure of the brain that is exceptional because it lacks a blood-brain barrier (a structure that controls the entrance of substances from the blood to the brain) and it controls many metabolic processes, including appetite and satiety. No effects on the main neuropeptides produced by the hypothalamus related to appetite and satiety have been noted in the mice. These last studies have been carried out in collaboration with the research group led by Miguel López at the University of Santiago de Compostela.
5) It works on a long-term basis: The effects of CNIO-PI3Ki were maintained over at least a 5-month period of treatment in mice, which suggests that resistance mechanisms are not developed. This is very important, as it is a common problem found in other compounds that affect metabolism.
6) Reversibility: The effects of CNIO-PI3Ki were reversible, which means that when the treatment was interrupted and a high-fat diet maintained, the mice regained weight. This indicates that CNIO-PI3Ki does not cause irreversible changes.

The next logical step, once the beneficial effects of CNIO-PI3Ki have been demonstrated in obese mice and monkeys, is to perform clinical trials on humans. “The leap from animals to humans is complex, expensive and full of uncertainties. Many treatments that are promising in animals turn out not to be effective in humans or toxicities appear that were not observed in animals. But, obviously, in spite of the uncertainties, we have to give it a try,” says Manuel Serrano. “Clinical trials require large investments and are undertaken with the aim of marketing a treatment. We are very optimistic about the possibility of entering into an agreement soon with a multinational pharmaceutical company interested in carrying out clinical trials with CNIO-PI3Ki to treat obesity and metabolic syndrome in humans,” says Serrano.

Genetically Engineered Bone Marrow Stem Cells on a Fibrin Patch Repairs Damaged Heart


Regenerative therapies for the heart have come a long way from the first clinical trials and injected bone marrow cells directly into the heart muscle. Despite the modest improvements shown in those earlier studies, it became clear that the vast majority of cells that were implanted into the heart died soon after their introduction. This single fact left researchers looking for a better way to deliver cells into the damaged heart.

Several laboratories have tried to condition the stem cells before their injection in order to “toughen them up” so that they do not tend to die so easily. While these experiments have worked well in laboratory animals, no clinical trials have been conducted to date with conditioned stem cells. Another strategy is to place the cells on a patch that is then applied to the dead heart tissue in order to promote healing of the heart.

The patch strategy was employed by Hao Lai and Christopher Wang and their co-workers at the Shanghai Institute of Cardiovascular Disease in Shanghai, China. Lai and others extracted bone marrow stem cells from the bones of Shanghai white pigs. These cells were cultured, and genetically engineered to expressed IGF-1 (insulin-like growth factor-1). Once IGF-1 expression was confirmed, the cells were loaded onto a fibrin patch and placed over the hearts of Shanghai white pigs that had just experienced laboratory-induced heart attacks. There were four groups of pigs: 1) those treated with fibrin patches with bone marrow stem cells that were not genetically engineered; 2) another group treated with fibrin patches that contained genetically engineered bone marrow stem cells that did not express IGF-1; 3) fibrin patches containing bone marrow stem cells that had been engineered to express IGF-1; and 4) a control group that was not treated with any cells or patches.

In culture, the IGF-1 engineered cells did not differentiate into heart muscle cells, and they did induce proliferation in Human Umbilical Vein Endothelial cells, which suggests that these engineered cells would induce the formation of new blood vessels.

When transplanted into heart injured pigs, the IGF-1-expressing cells on a fibrin patch significantly reduced the size of the infarct in the hearts, and increased the thickening of the walls of the heart. Gene expression studies showed that the IGF-1-expressing cells on the fibrin patch induced anti-cell death genes that promote cell survival. These cells also induced the growth of many new blood vessels and seemed to promote the growth of new heart muscle, but the cells on the patch are almost certainly not the source of these new cells, but resident stem cell populations in the heart probably were.  The increase in heart mass suggests that the implanted cells induced the resident stem cell populations in the heart to divide and differentiate into heart muscle cells.

This new technique proved safe and effective. It prevented remodeling (enlargement) of the heart and promoted cell survival. It is a technique that shows promise, especially since the fibrin patch is biodegradable and the bone marrow stem cells will not last indefinitely in the heart. These cells simply work by serving as a platform for the secretion of IGF-1 and perhaps other healing molecules.

Another caveat of this experiment is that the bone marrow stem cells were genetically engineered with lentivirus vectors. Because of the tendency for these vectors to insert genes willy-nilly into the genome, this is almost certainly not the safest way to genetically modify cells Finally, the improvements in these animals was significant albeit modest. In order for this technique to come to the clinic, it will have to induce better improvements in heart function. There were modest, albeit insignificant increases in ejection fraction. The ejection fraction will need to be increases for this technique to have a fighting chance to come to clinical trials. Nevertheless, this is a fine start to what might become a new strategy to treat patients with ailing hearts.

Stem Cell Researchers Develop New Method to Treat Sickle Cell Disease


Stem cells researchers from the Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at the University of California, Los Angeles (UCLA) have shown that a new stem cell gene therapy protocol can potentially lead to a one-time, lasting treatment for sickle-cell disease, which remains the nation’s most common inherited blood disorder.

This study was led by Dr. Donald Kohn and was published March 2 in the journal Blood. This paper details a method that repairs a mistake in the beta-globin that causes sickle-cell disease and, for the first time, shows that such a gene therapy technique can lead to the production of normal red blood cells.

People with sickle-cell disease are born with a mutation in their beta-globin gene.

missense_mutation3

Beta-globin is one of the protein chains that compose the protein hemoglobin. Hemoglobin is the protein in red blood cells that ferries oxygen from the lungs to the tissues and then returns to the lungs to load up with oxygen again and then goes back to the tissues. Red blood cells, which are made in the bone marrow, are packed from stem to stern with hemoglobin molecules, and normally are round, and slightly dished and flexible enough to squeeze through small capillary beds in tissues. The mutation in the beta-globin gene that causes sickle-cell disease, however, causes hemoglobin to form long, stiff rods of protein rather than tight, compactly packed clusters of hemoglobin. These protein rods deform the red blood cells and make them stiff, sickle-shaped, and unable to pass through tissue capillary beds.

sickle-cell-hemoglobin

These abnormally shaped red blood cells not only move poorly through blood vessels, but they also do not sufficiently carry oxygen to vital organs.

Sickle_cell 2

The stem cell gene therapy method described by Kohn and his colleagues corrects the mutation in the beta-globin gene in the bone marrow-based stem cells so that they produce normal, circular-shaped blood cells. The technique uses specially engineered enzymes, called zinc-finger nucleases, to eliminate the mutation and replace it with a corrected version that repairs the beta-globin mutation. Kohn’s research showed that this method has the potential to treat sickle-cell the disease if the gene therapy achieves higher levels of correction.

“This is a very exciting result,” said Dr. Kohn, professor of pediatrics and microbiology, immunology and molecular genetics. “It suggests the future direction for treating genetic diseases will be by correcting the specific mutation in a patient’s genetic code. Since sickle-cell disease was the first human genetic disease where we understood the fundamental gene defect, and since everyone with sickle-cell has the exact same mutation in the beta-globin gene, it is a great target for this gene correction method.”

Forcing Sugars on the Surfaces of Cord Blood Cell Increases Their Engraftment


When a child or adult needs new bone marrow, a bone marrow transplant from a donor is usually the only way to save their life. Without properly functioning bone marrow, the patient’s blood cells will die off, and there will be too few red blood cells to ferry oxygen to tissues or white blood cells to fight off infections.

An alternative to bone marrow from a bone marrow donor if umbilical cord blood. Umbilical cord blood does not require the rigorous tissue matching that bone marrow requires because the blood making stem cells from cord blood are immature and not as likely to cause tissue rejection reactions.. However, umbilical cord blood cells suffer from two drawbacks: low numbers of stem cells in cord blood and poor engraftment efficiencies.

Fortunately, some progress has been made at expanding blood-making stem cells from umbilical cord blood, and it is likely that such technologies might be ready for common use in the future. As to the poor engraftment efficiencies, a new paper in the journal Blood from the laboratory of Elizabeth J. Shpall at the University of Texas MD Anderson Cancer Center, in Houston, Texas reports a new way to increase cord blood stem cells engraftment efficiencies.

As previously discusses, delayed engraftment is one of the major limitations of cord blood transplantation (CBT). Delayed engraftment seems to be due to the diminished ability of the cord blood stem cells to home to the bone marrow. How are cells channeled to the bone marrow? A protein receptor called P- and E-selectins is expressed on the surfaces of bone marrow blood vessels. Cells that can bind these selectin receptors will pass from the circulation to the bone marrow. Thus binding selectin receptors is kind of like having the “password” for the bone marrow.

What does it take to bind the selectin proteins? Selectins bind to specific sugars that have been attached to proteins. These sugars are called “fucose” sugars. As it turns out, cord blood stem cells do not express robust levels of these fucosylated proteins. Could increasing the levels of fucosylated proteins on the surfaces of cord blood stem cells increase their engraftment? Shpall and her colleagues tested this hypothesis in patients with blood-based cancers.

Patients with blood cancers had their cancer-producing bone marrow stem cells destroyed with drugs and radiation. Then these same patients had their bone marrows refurbished with two units of umbilical cord blood. However, these cells in these cord blood units were treated with the enzyme fucosyltransferase-VI and guanosine diphosphate fucose for 30 minutes before transplantation. This treatment should have increased the content of fucosylated proteins on the surfaces of cells in the hope of enhancing their interaction with Selectin receptors on the surfaces of bone marrow capillaries.

The results of 22 patients enrolled in the trial were then compared with those for 31 historical controls who had undergone double unmanipulated CBT. There was a clear decrease in the length of time it took for cells to engraft into the bone marrow.  For example, the median time to neutrophil (a type of white blood cell) engraftment was 17 days (range 12-34) compared to 26 days (range, 11-48) for controls (P=0.0023). Platelet (a cell used in blood clotting) engraftment was also improved: median 35 days (range, 18-100) compared to 45 days (range, 27-120) for controls (P=0.0520).  These are significant differences.

These findings support show that treating cord blood cells with a rather inexpensive cocktail of enzymes for a short period of time before transplantation is a clinically feasible means to improve engraftment efficiency of CBT.  This is a small study.  Therefore, these data, though very hopeful, must be confirmed with larger studies.

High-Quality Cartilage Production from Pluripotent Stem Cells


High-quality cartilage has been produced from pluripotent stem cells by workers in the laboratory of Sue Kimber and her team in the Faculty of Life Sciences at The University of Manchester. Such success might be used in the future to treat the painful joint condition osteoarthritis.

Kimber and her colleagues used strict laboratory conditions to grow and transform embryonic stem cells into cartilage cells known as chondrocytes.

Professor Kimber said: “This work represents an important step forward in treating cartilage damage by using embryonic stem cells to form new tissue, although it’s still in its early experimental stages.” Kimber’s research was published in Stem Cells Translational Medicine.

During the study, the team analyzed the ability of embryonic stems cells to become cartilage precursor cells. Kimber and her colleagues then implanted these pre-chrondrocytes into cartilage defects in the knee joints of rats. After four weeks, the damaged cartilage was partially repaired and following 12 weeks a smooth surface, which looked very similar to normal cartilage, was observed. More detailed studied of this newly regenerated cartilage demonstrated that cartilage cells from embryonic stem cells were still present and active within the tissue.

Developing and testing this protocol in rats is the first step in generating the information required to run such a study in people with arthritis. Before such a clinical trial can be run, more data will need to be collected in order to check that this protocol is effective and that there are no toxic side-effects.

However, Kimber and her coworkers say that this study is very promising as not only did this protocol generate new, healthy-looking cartilage but also importantly there were no signs of any side-effects such as growing abnormal or disorganized, joint tissue or tumors. Further work will build on this finding and demonstrate that this could be a safe and effective treatment for people with joint damage.

Chondrocytes created from adult stem cells are being used on an experimental basis, but, to date, they cannot be produced in large amounts, and the procedure is expensive.

With their huge capacity to proliferate, pluripotent stem cells such as embryonic stem cells and induced pluripotent stem cells can be manipulated to form almost any type of mature cell. Such cells offer the possibility of high-volume production of cartilage cells, and their use would also be cheaper and applicable to a greater number of arthritis patients, the researchers claim.

“We’ve shown that the protocol we’ve developed has strong potential for developing large numbers of chondrogenic cells appropriate for clinical use,” added Prof Kimber. “These results thus mark an important step forward in supporting further development toward clinical translation.”

Osteoarthritis affects more than eight million people in the UK alone, and is a major cause of disability. It and occurs when cartilage at the ends of bones wears away causing joint pain and stiffness.

Director of research at Arthritis Research UK Dr Stephen Simpson added: “Current treatments of osteoarthritis are restricted to relieving painful symptoms, with no effective therapies to delay or reverse cartilage degeneration. Joint replacements are successful in older patients but not young people, or athletes who’ve suffered a sports injury.

“Embryonic stem cells offer an alternative source of cartilage cells to adult stem cells, and we’re excited about the immense potential of Professor Kimber’s work and the impact it could have for people with osteoarthritis.”

New Gene Therapy for Hemophilia


According to a multi-year, ongoing study, a new kind of gene therapy for hemophilia B could be safe and effective for human patients.

“The result was stunning,” said Timothy Nichols, MD, director of the Francis Owen Blood Research Laboratory at the University of North Carolina School of Medicine and co-senior author of the paper. “Just a small amount of new factor IX necessary for proper clotting produced a major reduction in bleeding events. It was extraordinarily powerful.”

Nichols published his work in the journal Science Translational Medicine, in which he showed that a genetically engineered retrovirus could successfully transfer new factor IX (clotting) genes into animals with hemophilia B to dramatically decrease spontaneous bleeding. To date, the new therapy has proven safe.

A new FDA-approved hemophilia treatment lasts longer than a few days but patients still require injections indefinitely at least once or twice a month. This new gene therapy only requires hemophilia patients to receive a one-time dose of new clotting genes instead of a lifetime of multiple injections of recombinant factor IX. This new gene therapy approach would involve a single injection and could potentially save money and provide a long-term solution to a life-long condition. A major potential advantage of this new gene therapy approach is that it uses lentiviral vectors, to which most people do not have antibodies that would reject the vectors and make the therapy less effective.

In human clinical studies, approximately 40 percent of the potential participants with hemophilia have antibodies in their blood against adeno-associated virus (AAV), which precludes them from entering AAV trials for hemophilia gene therapy treatment. Thus more people could potentially benefit from the lentivirus gene therapy approach.

Hemophilia is a bleeding disorder in which people lack a clotting factor. Therefore they bleed much more easily than people without the disease. People with hemophilia often bleed spontaneously into joints, which can be extremely painful and crippling. Spontaneous bleeds into soft tissues are also common and can be fatal if not treated promptly. Hemophilia A affects about one in 5,000 male births. These patients do not produce enough factor VIII in the liver. This leads to an inability to clot. Hemophilia B affects about one in 35,000 births; these patients lack factor IX.

The new method detailed in the Science Translational Medicine paper was spearheaded by Luigi Naldini, PhD, director of the San Raffaele Telethon Institute for Gene Therapy. Naldini and Nichols developed a way to use a lentivirus, a large retrovirus, to deliver factor IX genes to the livers of three dogs that have a naturally occurring form of hemophilia. They removed the genes involved in viral replication. “Essentially, this molecular engineering rendered the virus inert,” Nichols said. “It had the ability to get into the body but not cause disease.” This process turned the virus into a vector – simply a vehicle to carry genetic cargo.

Unlike some other viral vectors that have been used for gene therapy experiments, the lentiviral vector is so large that it can carry a large payload – namely, the clotting factor IX genes that people with hemophilia B lack. (This approach could also be used for hemophilia A where the FVIII gene is considerably larger.)

These viral vectors were then injected directly into the liver or intravenously. After more than three years, the three dogs in the study experienced zero or one serious bleeding event each year. Before the therapy, the dogs experienced an average of five spontaneous bleeding events that required clinical treatment. Importantly, the researchers detected no harmful effects.

“This safety feature is of paramount importance,” Nichols said. “Prior work elsewhere during the early 2000s used retroviruses for gene therapy to treat people with Severe Combined Immunodeficiency, but some patients in clinical trials developed leukemia.” Newer retroviral vectors, though, have so far proved safe for SCID patients.

To further demonstrate the safety of this new hemophilia treatment, Nichols and Naldini used three different strains of mice that were highly susceptible to developing complications, such as malignancies, when injected with lentiviruses. Fortunately, Nichols, Naldini and their coworkers found no harmful effects in these mice. Thus manipulating lentiviruses and converting them into lentiviral vectors made them safe for gene therapy.

“Considering the mouse model data and the absence of detectible genotoxicity during long-term expression in the hemophilia B dogs, the lentiviral vectors have a very encouraging safety profile in this case,” Nichols said.

This gene therapy approach requires more work before it can be used in human trials. For instance, researchers hope to increase the potency of the therapy to decrease spontaneous bleeding even more while also keeping the therapy safe.

Before the treatment, the hemophilia dogs had no sign of factor IX production. After the treatment, they exhibited between 1 and 3 percent of the production found in normal dogs. This slight increase was enough to substantially decrease bleeding events.

Nichols wants to try to boost factor IX production to between 5 and 10 percent of normal while still remaining safe. This amount of factor IX expression could potentially eliminate spontaneous bleeding events for people with hemophilia B.