New research study creates new opportunities for treating brain diseases

Immunotherapy entails treatment with antibodies; it is the fastest growing field in pharmaceutical development. In recent years, immunotherapy has successfully been used to treat cancer and rheumatoid arthritis, and the results of clinical studies look very promising for several other diseases. Antibodies are unique in that they can be modified to strongly bind to almost … Continue reading “New research study creates new opportunities for treating brain diseases”

Immunotherapy entails treatment with antibodies; it is the fastest growing field in pharmaceutical development. In recent years, immunotherapy has successfully been used to treat cancer and rheumatoid arthritis, and the results of clinical studies look very promising for several other diseases. Antibodies are unique in that they can be modified to strongly bind to almost any disease-causing protein. In other words, major potential exists for new antibody-based medicines.

The problem with immunotherapy for diseases affecting the brain is that the brain is protected by a very tight layer of cells, called the blood-brain barrier. The blood-brain barrier effectively prevents large molecules, such as antibodies, from passing from the bloodstream into the brain. It has therefore been difficult to use immunotherapy to treat Alzheimer’s and Parkinson’s disease, which affect the brain, as well as cancerous tumours in the brain.

It has been known for a long time that some large proteins are actively transported across the blood-brain barrier. These include a protein called transferrin, whose primary task is to bind to iron in the blood and then transport it to the brain. The research group behind this new study has taken advantage of this process and modified the antibodies they want to transport into the brain using components that bind to the transferrin receptor. Then, like a Trojan horse, the receptor transports antibodies into the brain. The number of modifications to and placement of the antibodies have proven to be important factors for making this process as effective as possible.

“We’ve placed them so that each antibody only binds with one modification at a time, despite being modified in two places. Our design thus doubles the chances of the antibody binding to the transferrin receptor compared with only one modification. We’ve successfully increased the amount of antibodies in the brain almost 100-fold, which is the largest uptake improvement that has ever been shown,” says Greta Hultqvist, researcher at the Department of Public Health and Caring Sciences at Uppsala University.

To try out the new format, researchers have used it on an antibody that binds to a protein involved in the course of Alzheimer’s disease. Without the modification, they could only detect very small quantities of antibody in the brain in a mouse model of Alzheimer’s disease, while they could detect high levels of the modified antibody in the same mice.

“From a long-term perspective, it’s likely that the new format can be used to effectively treat not only Alzheimer’s disease, but also other diseases affecting the brain,” says Dag Sehlin, researcher at the Department of Public Health and Caring Sciences at Uppsala University.

Best treatment option written in cancer’s genetic script

AML is an aggressive blood cancer that develops in bone marrow cells. Earlier this year, the team reported there are 11 types of AML, each with distinct genetic features. Now they report how a patient’s individual genetic details can be incorporated into predicting the outcome and treatment choice for that patient.

They built a knowledge bank using data from 1,540 patients with AML who participated in clinical trials in Germany and Austria, combining information on genetic features, treatment schedule and outcome for each person. From this, the team developed a tool that shows how the experience captured in the knowledge bank could be used to provide personalized information about the best treatment options for a new patient.

There are two major treatment options for young patients with AML — a stem cell transplant or chemotherapy. Stem cell transplants cure more patients overall but up to one in four people die from complications of the transplant and a further one in four experience long-term side effects. Weighing up the benefits of better cure rates with transplant against the risks of worse early mortality is a harrowing decision for patients and their clinicians. The team showed that these benefits and risks could be accurately calculated for an individual patient, enabling therapeutic choices to become personalized.

The team estimates that up to one in three patients would be prescribed a different treatment regimen using the tool compared with current practice. In the long term they hope the tool could spare one in ten young AML patients from a transplant while maintaining overall survival rates.

Senior author Dr Peter Campbell of the Wellcome Trust Sanger Institute said: “The knowledge bank approach makes far more detailed and accurate predictions about the likely future course of a patient with AML than what we can make in the clinic at the moment. Current guides use a simple set of rules based on only a few genetic findings. For any given patient, using the new tool we can compare the likely future outcomes under a transplant route versus a standard chemotherapy route — this means that we can make a treatment choice that is personally tailored to the unique features of that particular patient.”

The tool is currently available for scientists to use in research but needs further testing before it can be used to prescribe treatments in AML clinics.

Lead author Dr Moritz Gerstung of the European Bioinformatics Institute said: “It has long been recognised that cancer is a complex genetic disease. Our study provides an example of how detailed genetic and clinical information can be rationally incorporated into clinical decisions for individual patients. We tested this philosophy in one type of leukemia, but the concept could theoretically be applied in other cancers with difficult clinical decisions as well. Our analysis reveals that knowledge banks of up to 10,000 patients would be needed to obtain the precision needed for routine clinical application.”

Using large scale genetic studies as a source to predict the best treatment option for future patients is an idea that Genomics England is trying to build alongside similar programmes around the world, such as the National Institutes of Health Precision Medicine Initiative in the US.

The authors believe this paper is a step towards validation of genetic techniques as a route to personalized medicine.

Co-senior author Dr Hartmut Döhner of University of Ulm said: “Building knowledge banks is not easy. To get accurate treatment predictions you need data from thousands of patients and all tumour types. Furthermore, such knowledge banks will need continuous updating as new therapies become approved and available. As genetic testing enters routine clinical practice, there is an opportunity to learn from patients undergoing care in our health systems. Our paper gives the first real evidence that the approach is worthwhile, how it could be used and what the scale needs to be.”

New potential treatment for cancer metastasis identified

Metastasis is a hallmark of cancer and a leading cause of cancer death,” says the study’s senior author, Zhenkun Lou, Ph.D., of Mayo Clinic. “Despite great progress in cancer therapy, the prevention of cancer metastasis is still an unfulfilled challenge.”

For this study, Dr. Lou and his colleagues focused on triple-negative breast cancer, which is difficult to treat, because it does not exhibit receptors for estrogen, progesterone or the HER-2/neu gene, which are targets for many current breast cancer treatments.

“Prior published data suggested that CDK 4/6 inhibitors were not effective in reducing the growth rates of estrogen receptor negative breast cancer,” says Dr. Lou. “Our data confirmed that, while the rate of growth of triple-negative breast cancer was not affected by CDK 4/6 inhibitors, this class of drugs was able to significantly inhibit the spread of triple-negative breast cancer to distant organs when tested in multiple different triple-negative breast cancer models, including patient-derived xenografts.” Patient-derived xenographs involve the implantation of tumor tissue into an immunodeficient mouse which becomes an avatar to help identify which drug or drug combinations are most likely to be effective for an individual cancer patient.

Dr. Lou cautions that more research is necessary, however. If his findings are corroborated, it would be an important discovery that could expand the use of CDK 4/6 inhibitors to prevent the metastasis of many other cancers that exhibit a high level of the SNAIL protein.

“These findings may provide a new treatment for the prevention of cancer metastasis,” says study co-author Matthew Goetz, M.D., an oncologist and co-leader of the Women’s Cancer Program at Mayo Clinic. “Mayo Clinic is now developing new studies that will focus on the role of CDK 4/6 inhibitors and their potential to inhibit cancer metastasis in women with triple-negative breast cancer who are at highest risk for cancer metastasis.”