Toshihiko Nishimura

Senior Researcher | Stanford University

Transcript of the presentation An Absolute Requirement for Precision Medicine: Humanized Organ Study, given at the NTT Upgrade 2020 Research Summit, October 1, 2020

Hello everybody, I am Toshihiko Nishimura from Stanford University, Director, Stanford Lab for Drug, Device Development and Regulatory Science (SLDDDRS). Super aging, global warming, global transportation, global infection are all major points of concern. In addition, this year we have the COVID-19 pandemic. As you can see here, worldwide new COVID-19 patients are still increasing. Meanwhile, case counts per day in the United States are beginning to decrease. This pandemic has changed our daily life to digital transformation.

Even today, my presentation is being conducted online. And doctor and nurse care are now increased to telemedicine. Likewise, the drug development process is in need of major change, a paradigm shift, especially in vaccine and drug development for COVID-19. It should be safe, effective and faster. In the anesthesia department, which is the biggest department in the school of medicine, we have the Stanford Lab for Drug Device Development Regulatory Science, so-called SLDDDRS.

Chairman is Ron Pearl, and this lab’s leadership isRon, myself, and Steven Shafer. In the drug development, we have three major pains. One, exceedingly long duration, such as 20 years; huge budget; and very low success rate. General overview in the drug development, there are discovery, preclinical, clinical, regulatory stage. As you see here, 10 years in clinical stage is very long. We set several programs in SLDDDRS in each stage.

The “OMICs” program, single-cell programs, big-data, machine-learning, deep-learning, AI, mathematics/statistic programs, humanized animal program, SNS program, engineering program, and we have an annual symposium. Today in my talk, I’d like to explain limitations of mice science, significance of humanized mice science. Out of several programs, I focused on the humanized program. I believe this program is a potent game changer for drug development.

Mouse – when we think of animal experiments many people think of immediately, mouse. We have more than 30 kinds of inbred wild type, such as C57 black, KK yellow, BALB/c white, and so on. Using QA/QC defined wild type mice, 18 of them, given only one intervention, using mouse genomics, analyzed computational genetics, and then we succeeded to pick up one single gene in a week.

We have another category of gene-manipulated mice. Transgenic, knock out, knock in mouse. So far, registered 40,000 kind, as of today. Preclinical requirement from FDA, PMDA, regulatory science, are based on at least two kinds of animal models showing safety and efficacy. Combination of two-animals model are mouse and swine, mouse and non-human primate, and so on. Mice are very popular. Why?

Because mice are small enough, easy to handle, big database (that we have) and cost effective. However, it caused the low success rate. Why? Is this an issue. Speculation on the low success rate came from a gap between preclinical POC and clinical POC. Clinical stage further divides into FIH (first in human), phase one, phase two, phase three. FDA answered our question and speculation in Nature Biology, using 7,372 new submissions.

They found a 68 (percent) significant failure at phase two to three approval process. And in total 90% failure in the clinical stage. What can we summarize from this study? FDA confirmed that the big discrepancy is between preclinical POC and clinical POC. In other words, animal data were misrepresentative for humans. This Nature Biology report impacted our work significantly.

What is the solution for this discrepancy? FDA still requires vivo data from two species. One species is usually mice, but the FDA reported 90% failure in preclinical data, then a huge discrepancy between preclinical POC and clinical POC. Our interpretation is data from mice is sometime misrepresentative. Actually, mice and humans are different, especially the immune system and liver.

Some of the mice liver enzymes are missing which the human liver has. This is one huge issue to be tackled. To overcome this problem, we started a humanized mice program. What kind of humanized mice have we created? One is humanized immune mice. The other is humanized liver mice. What is the definition of a humanized mouse? They should have human genes, or human cells, or human tissues and/or human organs.

Well, let me share one preclinical stage example of a humanized mouse, that is, polio receptor mice. This program was led by Dr. Tatsuji Nomura, my mentor. Polio virus or polio virus vaccine usually required a non-human primate to test. In 13 years collaboration with FDA, WHO polio eradication program, finally, FDA, as well as WHO approved to replace non-human-primates test to transgenic PVR mice. This is 3Rs principle led by Russel and Burch.

To move forward this humanized mouse program, we need to advance donor side science, as well as recipient mouse science. Furthermore, human hormone like GM-CSF or G-CSF producing or human cytokine, IL-2, IL-4, IL-6, those producing NOG mice are required in the long run to maintain human cells in their body.

The founder generation and the further generation are here, Dr. Ito in CIEA, our colleague, has already created more than 100 kinds of NOG mice. Based on the 100 kinds of NOG mice, we succeeded to create the humanized immune mice. Red blood cell, white blood cell, platelets are beautifully reconstituted in NOG mice. The humanized liver mice are also succeeded to create. Using different human race, we have Asian liver humanized mouse, American-African humanized liver mice, Caucasian humanized liver mice. These are healthy humanized immune and liver model. On the other hand, we created disease liver humanized mice too. One example, congenital liver disease, Alagille syndrome patient model. The other models we have: infectious disease model, cancer model, and GVHD model, and so on.

Which stage or phase can humanized mice apply? Our objective is any stage, any phase will do. At first, we performed the experiment for the compound, which showed a huge discrepancy between preclinical POC and clinical POC.

FIAU showed this huge discrepancy. FIAU is nucleoside analogue and the potent anti-hepatitis B candidate. In the preclinical stage, it didn’t show any toxicity in mice, rat, dog and non-human primate. On the other hand, weighing into clinical stage and phase two, out of 15 subjects, five people died and the other ten showed very severe conditions. The reason why?

Because they used a traditional mice model. The traditional mice model did not predict this severe side outcome while the humanized mouse liver model demonstrated that within a few days. The chemistry data and pathophysiology data are reproduced in the  humanized liver mice model. Well, clinically, phase two and three requires a huge number of  human subjects. For example, COVID-19 vaccine development by Pfizer, AstraZeneca, Moderna, today their sample size is more than 30,000.

Vaccine development for COVID-19, Sinovac Wuhan in China, Oxford, AstraZeneca, Johnson and Johnson in United Kingdom. Moderna, Novavax in the U.S. Osaka University and AnGes in Japan. They are all in phase two and three. Discovery and preclinical and regulatory stage may become faster enough. However, clinical stage is still slow because the phase three requires a huge number of human subjects, 9,000 to 30,000. In my conclusion, a humanized mouse model shortens the duration of drug development. Humanized mice as well can increase the success rate of drug development.

Thank you to Ron Pearl and Steven (Shafer), Gary Peltz at Stanford, and CIEA, Dr. Ito and his team and or other colleagues. Thank you for listening.

An Absolute Requirement for Precision Medicine: Humanized Organ Study

toshihiko nishimura head shot

Toshihiko Nishimura
Senior Researcher | Stanford University