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Bleeding-control polymer gel for brain surgery, polymer implants attack brain cancer

Bleeding-control polymer gel for brain surgery, polymer implants attack brain cancer

A spray-on gel to staunch bleeding during brain surgery has been developed by New Jersey Institute of Technology. Surgeons can spray the gel onto a surgical site, and the natural bio-polymer solutions in the gel will cohere and control bleeding in the patient within 30 seconds. The gel can shorten an intracranial surgery by 30-45 minutes. It will translate into less time for the patient's skull to be open and less anesthesia, reducing both the possibility of infection and morbidity. Shorter surgeries also reduce hospital costs: The new gel is expected to save hospitals more than US$3000-4000 per case. The hydrogel derives from two polysaccharides that are simultaneously mixed and sprayed onto a surgical site. Once the hydrogel is mixed, it forms an adhesive and cohesive material that gelates within 30 seconds. The hydrogel solutions are made from natural materials and do not contain and blood or tissue components. That makes them highly biocompatible. The National Institute of Neurological Disorders and Stroke awarded a US$1.4 mln grant to Endomedix to support its research on the gel, technically classified as a medical device. Endomedix has been developing the gel, known as a surgical hemostat, since 2009. Its applied research phase has been successful – the company has two issued U.S. patents on the gel and will begin biocompatibility testing later this year. After the tests are finished, the firm will seek regulatory authorization to begin clinical studies.

Every year in the U.S. about 17,500 persons develop primary brain cancer. There are about 20,000 brain cancer surgeries each year. For most, even after surgery, prospects for a normal, healthy life remain grim as occurrence of relapses is common. Conventional post-surgery treatment of radiation and intravenous chemotherapy often prove unsuccessful. Drugs needed to fight the cancerous growth reach the brain in too-low concentrations to be effective. In addition, serious side effects associated with drug delivery, such as anemia and pulmonary fibrosis, have become common problem areas. A controlled drug-delivery system that can be implanted at the site of the removed tumor, has been developed. This will help some brain-cancer patients have a brighter future. Clinical tests have shown that polymer wafers impreg-nated with a cancer-fighting drug implanted after surgery can help prolong life. As the biodegradable wafers erode, they release the chemotherapeutic drug to prevent relapses. Moreover, drug delivery takes place over time without the adverse effects common to intravenous delivery. The novel system, called Gliadel®, consists of a biodegradable polyanhydride polymer matrix that incorporates a generic cancer-fighting drug, carmustine (BCNU). After removing the tumor, the surgeon simply places up to eight wafers into the cavity, then closes it. The wafers slowly degrade, releasing toxins directly to the cancerous tissue.
Researchers report that two highly successful clinical tests, involving patients in North America and Europe, have shown marked improvements in survival rates for those treated by the new method. The treatment system, offered by Guilford Pharmaceuticals, a Baltimore-based biotechnology company, is awaiting regulatory approval from the U.S. Food and Drug Administration. Dr. Henry Brem, professor of neurosurgery and oncology at Johns Hopkins Medical Institutions, describes the system's development as "very significant for the future treatment of brain cancers." He adds, "Use of biodegradable polymers to deliver prolonged high doses of chemotherapy directly to the tumor spares patients from systemic exposure to the drug. No other form of chemotherapy has shown such a dramatic improvement in survival with so few side effects. It offers physicians a brand new, effective weapon for fighting cancer." The most recent Phase III clinical tests of the Gliadel system took place in Europe. They involved patients undergoing surgery for the first time to remove fatal malignant gliomas, the most common type of primary brain cancer. In the randomized tests, either Gliadel wafers or placebos were implanted in 32 patients. Three weeks after surgery, all the patients underwent standard radiation therapy. Physicians tracked the patients for two years, or until death. One year after treatment, 63% of the Gliadel-treated patients remained alive, compared to only 19% of the placebo recipients. These results, states Dr. Brem, "confirm and extend the results of our U.S. clinical tests." With Dr. Brem as lead investigator, the first Phase III test involved 222 gravely ill persons. All in advanced stages of the illness, these patients experienced recurring tumors that required operations for the second or third time. 27 medical centers in the U.S. and Canada participated in the tests. An examination of the test results showed that six-month survival rates ranged from 47% for patients with placebo wafers to 60% with the Gliadel treatment. Patients with glioblastoma multiforme, the most common and severe form of brain tumor, showed even more dramatic results. For these patients, the six-month survival period increased from 36 in the placebo group to 56% for those given the BCNU drug wafer-a 55% improvement.

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