Treatment with the angiogenesis inhibitor Bevacizumab ( Avastin ) improved hearing and alleviated other symptoms in patients with neurofibromatosis type 2 ( NF2 ).
In a paper, published in the New England Journal of Medicine, Researchers from Massachusetts General Hospital ( MGH ) reported that Bevacizumab treatment successfully shrank characteristic tumors in a small group of NF2 patients, the first reported successful NF2 treatment not involving surgery or radiation.
NF2 is an inherited genetic disorder in which benign tumors develop throughout the nervous system. Vestibular schwannomas are the most common NF2-associated tumors, and although they grow slowly, they usually cause patients to lose all or most of their hearing by young adulthood or middle age. The tumors can be removed surgically or treated with radiation, but in patients with vestibular schwannomas on both sides, which is typical in NF2, such treatment usually leads to complete hearing loss. Growing vestibular schwannomas can also press on the brainstem, leading to headaches, difficulty swallowing and other serious neurologic symptoms.
Since vestibular schwannomas are benign tumors, it was believed that they did not stimulate formation of new blood vessels as malignant tumors do. However, when the Researchers studied tissue samples from NF2-related schwannomas, sporadic tumors not caused by NF2 and normal spinal nerves, they found evidence of excess blood vessel development and increased expression of angiogenesis-related molecules in both NF2-associated and sporadic vestibular schwannomas. With this suggestion that angiogenesis was involved in these tumors, members of the research team offered treatment with Bevacizumab, which is FDA-approved for treatment of several forms of cancer, to NF2 patients in danger of complete hearing loss or other significant neurological damage.
Among the first ten NF2 patients to receive Bevacizumab, treatment led to tumor shrinkage in nine, and six had 20 percent or greater reduction in tumor size. In those six patients, tumor shrinkage lasted from 11 to 16 months, longer than the four months typically seen in Bevacizumab treatment of malignant brain tumors. Of seven patients who had started to lose their hearing before treatment, four experienced some hearing restoration two returning to work or school as a result improvement that has also lasted for up to 16 months. In one patient without significant tumor shrinkage or hearing improvement ( he had lost all hearing prior to treatment ), treatment alleviated headaches and nausea caused by brainstem compression, allowing him also to return to school.
Source: Massachusetts General Hospital, 2009
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