Team:Tongji China/Integrated
Human Practice
Integrated Human Practice
In recent years, multiple ways of immunotherapy arise which leads to brand-new hope for patients with cancers and arouse our great interest to make further research. However, based on the clinical results of those like CAR-T, side effects happen with its unsteady curative effect. Improvement is needed and we are willing to take over this challenge.
Besides, this year unexpected scandals happened in Jilin-based Changsheng Biotechnology which has been ordered by the Chinese government to cease production of its fake rabies vaccine. It brings about great influence among society and gives rise to attention and debates of vaccine production. We are fully surprised by this scandal and reflect a lot. This issue about vaccine also plays a role in leading us to determine what we what to do to make a better world.
After plenty of research and design, we set up our project based on one specific system – Type III secretion system (T3SS) and developed our goal of design it as an antigen delivering agent for immunotherapy, which is promising in individualized treatment. Our primary thought is rough and is necessary to fill up the blank, therefore research from both professional and social field are required.
Though we could construct the major part of our project through self-searching on the internet and literature reading, there are some questions and negligible aspects when it comes to practical application and it is of great benefit if we could get advice from professional consultant. Therefore, we invited Professor Du Xin to assist us in aspect of bacterial immunity and possibility of bringing our project into practical medicine.
Dr. Xin Du (杜新) is a regulatory professional with unique combination of FDA and industry regulatory experience as well as international regulation knowledge and experience. He obtained his Ph.D degree from the University of Florida and completed his post-doctoral training at the National Institute of Health (NIH). He worked for US FDA, and pharmaceutical companies of Aventis-Pastuer, Wyeth, Novartis, BMS, NPS, Actinium and Advaxis. Currently, he is the Senior VP of Regulatory and Quality at Adlai Nortye USA Inc. He is an Executive Council member of SAPA.
We prepared several questions for Dr. Du, and had conversations with him for these questions.
1) About oral administration:
Dr. Du advised that the practical aspects are how to protect the orally administrated medicines from being digested or destroyed when the medicines go through the digestion system, and how to ensure the antigens could be delivered to the targets. Dr. Du recommended us to complete our projects focus on these important aspects.
→ Response: we solve this by coating our bacterial with capsule.2) Advantages in bacterial immunity compared to antigen-immunity
Dr. Du stated several advantages of bacterial immunotherapy. Firstly, the immune response by bacteria-based products could appear immediately; secondly the antigens carried by bacterial immunotherapy products could be designed more specific to target specific cancers; Thirdly, the antigens carried by bacterial immunotherapy products are less likely to be degraded; Thus, Dr. Du is very supportive to our research project.
→ Response: to know the bright future of bacterial immunity really encourages us to keep moving forward.3) Side effect in over-reactive bacterial immunotherapy products?
Like the CAR-T products, bacterial immunotherapy products could cause side effects, such as cytokine storm. To some extent, this type of side effects is an indication of that the products are working. To handle such side effects, there are co-medicines that can be used to reduce or control the side effects. Therefore, “Some of the risks are a part of the response mechanism of the bacterial immunotherapy products, the important thing we need to take care is, first, how to reduce the risks, second, if it happens, what medicine we could use to control the risks”.
→ Response: It brought up our attention in such possible side effects and we did more research later. We are confirmed that there is less possibility in side effects from our production. Even if there are such side effect, there are also existing solutions to handle them.4) Clearance of exogenous bacteria.
As is mentioned by Dr. Du, human body has its natural mechanism to clear the exogenous bacteria. In addition, to ensure the full clearance of the exogenous bacteria, antibiotics are used in the clinical trials when such bacterial immunotherapies are used.
→ Response: We decide to obey the rule of this “parallel protections” and design a light-control suicide system inside our bacterial.5) Encouragement
“To be or not to be, that may not be your chief question; the key is to identify the problem and find pathway to solve it.”
Apart from those main points for the design, Professor Du also makes significant advice in experimental designing which is of great use.
We learned through researches that the P. aeruginosa has certain invasive ability, which means they will invade the cells, and eventually enter the blood after oral administration. We concerned about the safety issue about P. aeruginosa and its advantages over Salmonella and Yersinia, therefore, professional instruction of using P. aeruginosa orally is necessary.
Fang Bai (白芳), Associate Professor, School of Pharmacy, Nankai University, focusing on microbial and biochemical
drugs and making a great progress in utilizing P. aeruginosa Type III secretion system to deliver transcription factors to achieve the gene editing of PSCs and to trigger diferenciation of ESCs. Also professional at the threatment of P. aeruginosa.We received professional instructions in the following aspects:
- The safety issue on P. aeruginosa
- The advantages over Salmonella and Yersinia
- The advantages of oral administration over intravenous injection
Introduction1:
The attenuated strain you use are auxotrophic delta 9 in which μA gene is mutated. This strain can only grow in the presence of D-type glutamate. The human body does not contain D-type glutamate. So, the P. aeruginosa will cleave when it enters the human body. Secondly, because it is oral intake, the number of bacteria in the blood will be very small. Even if the auxotrophic bacteria enter the blood, they do not have the ability to self-reproduce and do not cause infection.
Introduction2:
Salmonella can colonize in the gut and enter the intestinal epithelial cells. Studies have shown that P. aeruginosa cannot colonize in the intestine, so the time of function time of the bacteria after entering the intestine is limited. Since it is not the bacteria colonized in the intestine, the microorganisms originally present in the intestine threaten its survival, so does the immune system. In other words, the intestinal flora is the first major threat to the P. aeruginosa, followed by the intestinal immune system. Therefore, in the intestinal tract, the P. aeruginosa will be cleared a lot so using it will be relatively safe.
One of the features of your system is the use of a Type III secretion system to inject antigens into cells. If we need to apply antigen to anti-tumor immunity, we need to activate the reaction of CD8+ T cells, which is the cytotoxic response. Therefore, these antigens must be released into the cytoplasm of antigen-presenting cells in the form of a soluble protein, which can be extracted by MHC class I molecules to activate the CD8 response. Our system of P. aeruginosa, it happens to use its type III secretion system to inject antigens into the cell, and the P. aeruginosa itself does not enter the cell.
Introduction3:
I think that for the treatment of cancer, if it is a solid cancer, you can actually consider the method of injection, or oral presentation through the intestines can also be a good way. About this intravenous injection you mentioned. We have also done intravenous injections experiment. After intravenous injection, P. aeruginosa is more likely to gather in two organs. One is the liver and the other is the spleen. We found that P. aeruginosa can inject proteins into the spleen's various immune cells such as parenchyma cells, neutrophils, and macrophages through the type III secretion system. So, I think for you, still do oral, the intestines are better.
All those instructions had great effect on our following design on the project, some of which also provided support and encouragement to our idea.
For the promising application of our project to people’s health condition, it is significant to consider the actual application and possible patient responses and promote our design specifically. Therefore, we made our visit to a doctor Likun Hou in lung cancer at Lung Hospital affiliated to Tongji University.
Here are points of view from the doctor:
1) Individualized Treatment of cancer would be promising in future. Current therapy shows different effects in different clinical cases, sometimes it is confused even to doctors that whether the common therapy could work to specific patient. With the development of NGS (next generation sequencing), it would be a trend to treat patients more individualized.
2) The main limitation in future Individualized Treatment is the common standard for selection of antigens. It has already been available for a great amount of companies to do the sequencing, what matters most would be the way to select target antigens, which a standard for selecting is required.
3) Possible patients’ attitude towards our products:
We are concerned that whether the patient would refuse to intake our products for it depends on live bacterial-delivery. However, doctor Hou claimed that what patients care most is the effect of your product. As long as it has effects in curing the illness, they’d love to have a try. Take PD-1 inhibitor as an example. Despite its high expense and relative low rate for curing (around 30%), there are still patients choose to take it. Therefore, there is no need to worry about refuses from patients’
4) Opinions to our projects:
The idea is quite interesting. First it would reduce the cost of immunotherapy, despite the fact that current research for completing this therapy would take great amount of money. Secondly, It seems more safe compared to current immunotherapy such as CAR-T, which may leads to less side effects. Therefore, I suppose your project has great potentials.
To guarantee that our project would eventually develop practical medicine product for cancer therapy, we visited local pharmaceutical factory – Shanghai Roche Ltd. for advice in medicine capsules. After the visit of workshops for capsule coating, we were suggested that the capsule coats were available to buy in several companies, which they offered us a list to choose. Besides, they recommended that since our final products are in small amount, it was possible to acquire capsules from their recommended companies and coat our products by ourselves in the lab. Besides, they offered to assist the design of the capsules, accessory compounds adding and operation procedures for coating if was needed.
