Gene Therapy Demonstrates Benefit In Patients With Rheumatoid Arthritis

Researchers have reported the first clinical evidence that gene therapy reduces symptoms in patients with rheumatoid arthritis, an important milestone for this promising treatment which has endured a sometimes turbulent past.

Described in the February issue of the journal Human Gene Therapy the findings stem from a study of two patients with severe rheumatoid arthritis conducted in Germany and led by an investigator at Beth Israel Deaconess Medical Center (BIDMC).

Originally conceived as a means of treating genetic diseases, such as cystic fibrosis and hemophilia, gene therapy involves implanting a normal gene to compensate for a defective gene in the patient. The first clinical trial to test gene therapy was launched in 1990 for the treatment of a rare, genetic immunodeficiency disease.

"This study helps extend gene therapy research to nongenetic, nonlethal diseases," explains principal investigator Christopher Evans, PhD, Director of the Center for Advanced Orthopaedic Studies at BIDMC. "Rheumatoid arthritis [RA] is an extremely painful condition affecting multiple joints throughout the body. Arthritis is a good target for this treatment because the joint is a closed space into which we can inject genes," adds Evans, who is also the Maurice Muller Professor of Orthopaedic Surgery at Harvard Medical School.

A classic autoimmune disease, RA develops when, for unknown reasons, the body's immune system turns against itself, causing joints to become swollen and inflamed. If the disease is inadequately controlled, the tissues of the joint are eventually destroyed. Although anti-inflammatory agents and biologics can help to mitigate symptoms, there is no cure for the condition, estimated to affect more than 2 million individuals in the U.S. alone.

Evans has spent many years studying the molecules responsible for the breakdown of cartilage in patients with arthritis, identifying interleukin-1 as a good target. But, he adds, once he had this answer, another question was not far behind: How could he effectively reach the joints to block the actions of this protein?

Gene therapy provided the answer.

By implanting a gene in the affected joint, he was able to stimulate production of a human interleukin-1 receptor antagonist protein, which serves to block actions of the interleukin-1 protein.

"The idea is that by remaining in place, the new gene can continuously block the action of the interleukin-1 within the joints," says Evans. "In essence, the gene becomes its own little factory, continuously working to alleviate pain and swelling."

In 2005, in a study published in the Proceedings of the National Academy of Sciences (PNAS), Evans and colleagues demonstrated that the IL-1Ra gene could be safely transferred to human joints in patients with RA. In this new paper, the authors aimed to prove that the therapy was not only safe, but that it was of therapeutic benefit.

Two study subjects were recruited. (The number reduced from six study subjects following severe adverse events in an unrelated gene therapy trial taking place elsewhere, according to Evans.) Both subjects were postmenopausal females under the age of 75 with a diagnosis of advanced rheumatoid arthritis. After tissue was removed from the subjects' knuckle joints, a harmless retrovirus was inserted into the tissue cells, in order to serve as a "vector" to transport the gene into the patients' joints. After being placed in culture to grow and replicate, the cells were injected back into the afflicted joints.

After four weeks, patients reported reduced pain and swelling, according to Evans. "In one of the two subjects, these effects were dramatic, and the gene-treated joints remained pain-free even though other joints experience flares." Subsequent laboratory tests showed that tissues removed from the subject's joint tissue synthesized lower amounts of disease-related proteins, confirming that the reduction in pain and swelling resulted from the actions of the implanted gene.

"Existing treatments for rheumatoid arthritis are costly and need to be administered regularly," says Evans, adding that in addition to risk of side effects, not all patients respond well. "This paper provides us with the first real evidence that painful symptoms can indeed be lessened through gene therapy."

Ongoing work will focus on the use of gene therapy for the treatment of osteoarthritis, as well as rheumatoid arthritis.

This study was funded, in part, by grants from the National Institutes of Health and Orthogen, a German biotechnology company.

Study coauthors include Peter Wehling, Julio Reinecke, Axel Baltzer, Marcus Granrath, Klaus Schulitz, Carl Schultz, and Rudiger Krauspe of the University of Dusseldorf School of Medicine, Germany; Theresa Whiteside, Elaine Elder and Paul Robbins of the University of Pittsburgh School of Medicine; and Steven Ghivizzani of the University of Florida College of Medicine.

Is There A Relationship Between Sleep-wake Rhythm And Diabetes?

An international research team with German participation including Helmholtz Zentrum München, among other institutions, has succeeded in identifying a new gene variant which is associated with elevated fasting glucose levels and a high risk for type 2 diabetes. The gene mediates insulin secretion indirectly via the release of melatonin, which implicates a previously unknown relationship between the sleep-wake rhythm and the fasting glucose level. The finding could open up new possibilities of treatment which go far beyond the primarily symptomatic therapy approaches to diabetes that have been practised until now.

Diabetes mellitus and diabetes-associated late complications are among the most frequent chronic diseases and causes of death worldwide. In Germany there are approximately six million people with type 2 diabetes who are aware that they have the disease. In addition, there is a relatively high estimated number of undiagnosed diabetics. Besides lifestyle factors such as overweight and lack of exercise, genetic factors play an important role in the pathogenesis of this disease.

The international MAGIC Consortium (MAGIC = Meta-Analyses of Glucose and Insulin-related traits Consortium) combined the data from 13 case-control studies with over 18,000 diabetic and 64,000 non-diabetic study participants and was able to identify a variant of the MTNR1B gene which is associated with both elevated fasting glucose levels as well an elevated risk for type 2 diabetes. The goal of the MAGIC Consortium is to identify gene variants which regulate the fasting glucose levels in healthy individuals.

Germany is represented within the framework of the KORA studies by scientists of the Helmholtz Zentrum München (Assistant Professor Thomas Illig; Director of the KORA studies: Professor H.-Erich Wichmann) and the German Diabetes Center in Düsseldorf (Dr. Wolfgang Rathmann, Dr. Christian Herder; Direktor: Professor Michael Roden).

The MTNR1B gene is expressed in insulin-producing islet cells, among other cells, and encodes one of the two known melatonin receptors. It is assumed that this receptor inhibits the release of insulin via the neural hormone melatonin. The melatonin level in the body is high at night and declines in daylight, whereas the insulin level is higher during the day than in the night. Taken together, these new data implicate an association between the sleep-wake rhythm, the so-called circadian rhythm, and fasting glucose levels, which was not known previously.

Until now an efficient strategy for prevention and for therapies to treat the cause of the disease has been missing in diabetes research. The Helmholtz Zentrum München is working intensively on new approaches in the study and treatment of diabetes. Further studies will show which role melatonin plays in the regulation of insulin secretion, fasting glucose levels and the development of diabetes and whether this finding will lead to new treatment options.

Target That Could Ease Spinal Muscular Atrophy Symptoms Discovered

There is no cure for spinal muscular atrophy (SMA), a genetic disorder that causes the weakening of muscles and is the leading genetic cause of infant death, but University of Missouri researchers have discovered a new therapeutic target that improves deteriorating skeletal muscle tissue caused by SMA. The new therapy enhanced muscle strength, improved gross motor skills and increased the lifespan in a SMA model.

“This therapy does not directly target the disease-causing gene; instead it targets the pathways that affect muscle maintenance and growth,” said Chris Lorson, investigator in the Christopher S. Bond Life Sciences Center and associate professor of veterinary pathobiology in the MU College of Veterinary Medicine. “We administered a particular protein, follistatin, to SMA mouse models to determine if enhanced muscle mass impacts the symptoms of SMA. After treatment, the mice had increased muscle mass, gross motor function improvement and an increase in average life span of 30 percent.”

 With the therapy, MU researchers inhibited myostatin, a protein that limits muscle tissue growth. Myostatin activity can be reduced significantly by enabling several proteins that bind to myostatin, including follistatin. When myostatin is inhibited, muscle mass and strength increase.

SMA is caused by the loss of survival motor neuron-1(SMN1). Humans have a nearly identical copy gene called SMN2. Because of a single molecular difference, SMN2 alone cannot compensate for the loss of SMN1.

“While most work in the SMA field has logically focused on targeting the SMN2 gene, the results of this study suggest that skeletal muscle is a viable therapeutic target that may reduce the severity of some SMA symptoms,” said Lorson, who also is the scientific director for FightSMA, a private spinal muscular atrophy research foundation in Richmond, Va. “Because follistatin does not alter the expression level of SMN protein, the most effective treatment would combine strategies that directly address the genetic defect in SMA as well as SMN-independent strategies that enhance skeletal muscle.”

In Jan 2009, Lorson was awarded a $370,000 grant from the Muscular Dystrophy Association to continue his research on the role of muscle in SMA.

Gene Abnormality Found To Predict Childhood Leukemia Relapse

Scientists have identified mutations in a gene that predict a high likelihood of relapse in children with acute lymphoblastic leukemia (ALL). Although the researchers caution that further research is needed to determine how changes in the gene, called IKZF1 or IKAROS, lead to leukemia relapse, the findings are likely to provide the basis for future diagnostic tests to assess the risk of treatment failure. By using a molecular test to identify this genetic marker in ALL patients, physicians should be better able to assign patients to appropriate therapies.

The findings of the Children's Oncology Group (COG) study, led by scientists from St. Jude Children's Research Hospital, Memphis, Tenn., the University of New Mexico Cancer Research and Treatment Center, Albuquerque, N.M., and the National Cancer Institute (NCI), part of the National Institutes of Health, appear online Jan.7, 2009, in the New England Journal of Medicine, and in print on Jan. 29, 2009.

ALL, a cancer of the white blood cells, is the most common childhood cancer, in that it affects about one in 29,000 children annually. Using currently available therapies, cure rates for ALL are now upwards of 80 percent. However, those therapies carry with them substantial side effects, and even with treatment, only 30 percent of children who experience a relapse of ALL will survive five years. Determining the risk of relapse faced by an individual patient would help physicians tailor treatment intensity appropriately, but until now there has been no good marker for predicting outcome.

"Great progress has been made in recent years in improving the cure rate of childhood ALL," said Stephen Hunger, M.D., chairman of the COG ALL committee and the lead COG investigator on this study. "The findings of this study help us further subdivide those patients who are unlikely to be cured, and identify patients in whom different therapies should be tested."

In the study, researchers analyzed genetic data on leukemia cells obtained at diagnosis from 221 children with high-risk leukemia (i.e. a high chance of relapse) who had been treated in an existing COG study. They conducted their analysis using microarrays and DNA sequencing – technologies which allow researchers to quickly and efficiently identify and analyze multiple genes simultaneously in the same cell. Using these technologies to identify genetic abnormalities in leukemia cells, the investigators examined the DNA of the leukemia cells at the time of diagnosis and then determined if any of the identified genetic changes predicted relapse. To confirm that specific genetic changes were associated with relapse, the scientists also examined a second group of 258 children with ALL who were treated at St. Jude.

"We looked across the genome in an unbiased fashion in an attempt to pull out any genes that were significantly associated with outcome," said Charles Mullighan, M.D., Ph.D., assistant member in the St. Jude Department of Pathology and the paper's first author. "From these findings, we identified a group of genetic abnormalities that together predicted poor outcome."

The most significant association was with the deletions or changes in the IKAROS gene. Mutations of IKAROS were shown to identify a subgroup of patients who were treated in the COG study that had a very poor prognosis. The prognostic significance of these genetic alterations was validated in the independent St. Jude patient group, a finding of particular importance since different types of therapies were used in these two groups of patients.

Previous research has shown that the IKAROS gene serves as the blueprint for the production of the IKAROS protein, which regulates the activity of many other genes. The IKAROS protein plays an essential role in the development of lymphocytes, the white blood cells that, when changed, give rise to pediatric ALL. The way in which IKAROS abnormalities contribute to the development of relapse remains to be determined.

The study also examined gene expression in the leukemia cells using microarray chips, and found that leukemia cells from patients with IKAROS alterations expressed primitive, stem cell-like genes, suggesting that the cells are less mature and possibly more resistant to the effects of drugs used to treat ALL. "These findings show how detailed analysis of leukemic cells using complementary techniques can enhance our understanding of the genetic basis of leukemia," said co-author Cheryl Willman, director and CEO, University of New Mexico Cancer Research and Treatment Center.

The researchers also tested whether the presence of IKAROS alterations was associated with levels of minimal residual disease, another measure of treatment response in ALL.

"Measurement of levels of minimal residual disease is widely used to monitor treatment responsiveness and also to alter patients' therapy if they have a very poor response to treatment," said James Downing, M.D., St. Jude scientific director and the paper's senior author. "An important analysis we conducted was to see whether identifying the association of IKAROS alterations with poor outcome added anything to just measuring levels of minimal residual disease. And, indeed, it did."

The researchers' analysis indicated that identifying IKAROS alterations may be clinically useful and will complement existing diagnostic tests and measurement of minimal residual disease levels.

While a clinical test for alterations of IKAROS could prove valuable for predicting poor outcomes in children with ALL, complexities remain. There are different types of deletions in the gene, some that involve the entire IKAROS gene and others that involve only parts of the gene. Because the genetic alterations in IKAROS in ALL are not uniform or limited to a single mutation or deletion, it may be necessary to develop a panel of different tests to detect IKAROS lesions and identify which patients are at highest risk for relapse.

This research was done as part of the NCI Therapeutically Applicable Research to Generate Effective Treatments (TARGET) initiative, which seeks to utilize the study of genomics to identify therapeutic targets in order to develop more effective treatments for childhood cancers. The first two cancers being studied in the program are ALL and neuroblastoma, a cancer that arises in immature nerve cells and affects mostly infants and children. Combined, these two cancers account for 3,000 new cases each year, and in both cancers, there are some children who have a very favorable prognosis and others who are at high risk for treatment failure. By determining the genetic factors that distinguish these groups, the hope is that researchers can use this information to improve patient outcomes and develop better treatments, particularly for those in the high-risk group.

"In the long term, our goal is to develop effective therapeutic interventions, directed toward vulnerabilities that leukemia cells acquire as a result of the genomic abnormalities identified through the TARGET initiative," said Malcolm Smith, M.D., Ph.D., of NCI's Cancer Therapy Evaluation Program.