By Ai Yamanami
Yomiuri Shimbun Staff Writer
The Japanese government has approved a therapeutic drug for neurofibromatosis type 2 (NF2), an intractable disorder that affects the auditory nerves, the first such approval in the world.
On Friday, the Health, Labor and Welfare Ministry approved the expanded use of Avastin -- an anti-cancer drug with the generic name of bevacizumab -- to treat NF2, according to Chugai Pharmaceutical Co.
The genetic disorder causes tumors to develop typically on the auditory nerves on both sides of the intracranial cavity, causing hearing loss and dizziness. It affects roughly 1 in 25,000 to 33,000 people, and there are said to be about 800 patients in Japan. The onset of symptoms occurs on average at a relatively young age -- between 18 and 24 years old -- significantly impacting the patient's daily life.
As the disorder progresses, the tumors can compress the brainstem or develop on other nerves. Previously, there had been no effective drug to treat the disorder. The average age of death is 36.
It is difficult to preserve a patient's hearing if surgery or radiation therapy is attempted, so many have hesitated to seek early treatment. Patients have therefore long awaited the arrival of a therapeutic drug.
Avastin is a molecular-targeted drug developed by major Swiss pharmaceutical company Roche Holding Ltd., the parent company of Chugai. The drug binds with a protein that promotes the growth of new blood vessels to inhibit its activity, thereby suppressing tumor growth. It was launched in Japan in 2007 and is currently prescribed to patients with rectal, ovarian and other cancers.
In 2013, Fukushima Medical University began clinical research treating NF2 with Avastin, after an overseas study reported that the drug is effective against the disorder. Six years later, the institution launched a physician-led clinical trial to study the drug's efficacy and other factors.
The trial faced several challenges. Due to the rarity of the disease, the patient pool was small. The COVID-19 pandemic, meanwhile, caused delays, and financial difficulties also emerged. Eventually, questions began to be raised over whether it was possible to continue the trial. However, Fukushima Medical University succeeded in enlisting the help of 11 medical institutions across Japan. Chugai also assisted the university in gathering data on the disorder.
In the clinical trial, a group of patients prescribed Avastin throughout their initial treatment periods was compared with a group that did not receive the drug during the first 24 weeks. The results showed no significant difference in the proportion of patients whose hearing improved. However, there was a difference of about 11% in the degree to which patients maintained or improved their hearing. The trial also confirmed a trend of tumors shrinking.
The clinical trial observed side effects such as high blood pressure, but the overall safety level was considered satisfactory.
Fukushima Medical University Prof. Masazumi Fujii, a neurosurgery specialist who led the clinical trial, said he hopes that the government's approval of the drug "will increase the possibility that patients will have a new option."
He added, "We will continue to contribute to the research and development of treatments for rare and intractable diseases."
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This article is from The Yomiuri Shimbun. Neither Dow Jones Newswires, MarketWatch, Barron's nor The Wall Street Journal were involved in the creation of this content.
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June 22, 2026 22:25 ET (02:25 GMT)
Copyright (c) 2026 The Yomiuri Shimbun
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