TOP > Video Feature > Mariko Tosu, Ph.D.

Vol.17,November 2019

Mariko Tosu, Ph.D.

President & CEO Braizon Therapeutics. Inc.

Background and Goals of the Company

Braizon Therapeutics develops so-called drug delivery technology to deliver drugs to the brain. This technology is based on the research results of the collaborations between Professor Kazunori Kataoka, from the University of Tokyo and now Director of the Nanomedicine Innovation Center, and Professor Takanori Yokota, a medical doctor in neurology at Tokyo Medical and Dental University. The research results of these two medical and engineering collaborations have been implemented in society.

The brain does not easily allow the passage of medicine. This is because the brain has a blood-brain barrier that prevents the brain from passing unnecessary things, but only passing through what is necessary for itself.

Although it is difficult to develop drugs for the central nervous system due to this mechanism of preventing unnecessary things from passing into the brain, these results are due to research to solve this problem. This company was established for implementing these research results.

Features of the Research

I mentioned earlier that there is a mechanism in the brain that lets it pass what it needs. There is a molecule called “Glucose Transporter 1” (GLUT1) that is involved in the mechanism by which the brain takes glucose, which is a large energy source.
When using this molecule to deliver a drug, there are problems such as having to cover it with glucose and attaching glucose to the drug.

We produce a small molecule called a nanoparticle, and put the drug in this molecule. Then, the surface of the nanoparticles containing this medicine is covered with glucose. This is the mechanism by which nanoparticles modified with glucose and containing the drug are transported to the brain via the glucose transporter 1 as mentioned earlier.

Until now, only 0.1% of drugs that pass the blood-brain barrier, in contrast our technology has achieved about 6%. Currently, this is the highest rate that is delivered to the brain in the world now.

The other is a very small capsule called nanoparticles that can be filled with any drug. Various molecules such as low molecular weight compounds, antibody drugs that are attracting attention as future drugs, nucleic acid drugs, and peptides can be placed in these particles.

The main feature of our technology is that the particles are administered during fasting, that is, on an empty stomach. It is the same as not eating at the time of a health checkup. Fasting overnight, then the nanoparticles are administered. Then, after eating a meal and producing glucose, blood sugar rises and particles enter the brain with it.

Since other organs also require glucose, there are glucose transporters that deliver them to various organs such as the liver and heart. However, the accumulation of nanoparticles by blood sugar control is a phenomenon that can only be seen in the brain. Hence, this is a great characteristic that it can deliver drugs specifically to the brain.

Recent Advances

We are not developing medicines ourselves. Our clients are pharmaceutical companies that have drugs that they want to deliver to the brain. The collaboration of providing our technology to such pharmaceutical manufacturers leads to the co-developing and creating new drugs to reach the brain. We have already started joint research with about four pharmaceutical companies in Japan and overseas.

This is our main business model, but we also want to make medicine.

Since it will be in the form of nanoparticles, even if the drug itself is an existing drug, it will become a new drug when placed inside them. When this chemotherapeutic agent is effective if it goes to the brain, it is micellized and delivered to the brain. I think this is a way to do it.

Another thing is completely new. As we continue to age, the number of patients with neurodegenerative diseases, Alzheimer’s, Parkinson’s disease, Huntington, etc. will increase. Researchers are researching new drugs, but by scouting such academia seeds and combining with our technology, we can find more effective drugs. We want to develop them.


We are often asked, “What kind of company do you want to be?”
We want to be an Intel in the field of brain central nervous system because we are a strong company regarding our platform. We want to put a sticker saying ‘Braizon inside’ on boxes of brain medicine for brain diseases of the central nervous system produced by pharmaceutical companies all over the world. Just like “Intel Inside”.

Now, we are focusing on drug discovery, but in the future, not only brain pathology but also brain development and functional parts will be elucidated at the substance level. There is a possibility that substances could be delivered to the brain to prevent diseases, or for healthier lives. Even if it is 30 to 40 years later, the blood brain barrier will not disappear. I think that in the future, our technology will be useful not only for drugs but also for other such technologies.

Expectations of KINGSKYFRONT

KINGSKYFRONT has many kinds of facilities and in particular, the nanomedicine innovation center where we are based, is a venture incubation and a global research center for nanomedicine. That is our great advantage.

We now have a lab in Boston. As you know, Boston has a good environment with a well-developed venture ecosystem. There, not only networking of researchers and research laboratories, but also business matching and matching with venture capital move with great dynamics.

Big companies and ventures are based at KINGSKYFRONT. In such an environment, networking, matching, how to attract money is very important. I expect KINGSKYFRONT to create an environment where it can be said that there are merits in funding and that it will become a status to locate at KINGSKYFRONT.