Skin cells and neurons contain the same genetic code, but both cells are morphologically and characteristically different. The skin is able to regenerate itself constantly through regeneration and repair. Once neurons differentiate, they are unable to replicate themselves, and regeneration after traumatic situations like stroke are limited. Existing therapies for stroke patients include thrombolysis, catheters, and anticoagulants. All of these therapies aim to remove the blood clot in one of the brain’s arteries that causes the stroke. However, none of the existing therapies attempt to ameliorate neurons that may have been scarred as a result of the stroke. We believe that our Trojan horse therapy should be used in conjunction with existing therapies that remove blood clots to maximize patient recovery in the acute phase (within 3 months) of a stroke, and ideally several hours after a patient suffers a stroke. After interviewing Dr. Imama Navqi at Columbia University, we came to the conclusion that transvascular injection is the most effective way to deliver the NeuroTrojan therapy. Transvascular injection means that our therapy can be directly injected into arteries that lead to the brain with a thin, flexible catheter, where they can then be carried across the Blood-Brain Barrier through receptor-mediated transcytosis. This is a major advantage over a delivery method like a pill, where the therapy is not concentrated in the brain.
Through meeting with Dr. Costain, we identified that there was potential for more complex therapies than NT-3 or FGF-2, like nanoparticles, to be delivered into the brain by binding with HIRMAb and crossing the Blood-Brain Barrier. While there is no research in this area, our team believes that this field may be of interest for future stroke therapies.
Brownian motion is a concept in fluid dynamics where microscopic particles suspended in liquids or gases will move in a random motion. Our collaborator, Lambert High School, informed us to consider Brownian motion as a potential risk in our proposed implementation. Essentially, while our Trojan horse therapy is suspended within the blood in the arteries, it may not be taken up by endothelial cells, but rather pass through the artery. Considering the risks to our proposed implementation, our team chose to further investigate this concept by interviewing Dr. Greenfield at Cornell Weill Medicine. Dr. Greenfield had conducted several clinical trials with transvascular injection, and was able to describe the procedure in more detail. We learned that a special type of catheter could be inserted through the groin to a very specific location in an artery, near where a stroke had occurred. There, the catheter can create an occlusion balloon. This balloon temporarily stops blood flow through the artery. We were worried that this might harm stroke patients, but Dr. Greenfield confirmed that it was already in use as a safe, effective method. However, it allows for the catheter to attach to the arterial wall and deliver therapeutics very close to the target area, maximizing the therapy’s efficiency. If implemented in the real world, NeuroTrojan will adopt this implementation strategy.
Our therapy seeks to target patients within the acute phase of suffering a stroke, which is less than 3 months. Dr. Naqvi advised us to read “Time is Brain” by Jeffrey Saver. This paper emphasizes the relationship between time after a stroke occurs and neuron death. While a stroke is an instant effect, the duration of time in which neuron death occurs is on average 10 hours (ranging from 6 to 18 hours). Every minute after a stroke, 1.9 million neurons, 14 billion synapses, and 12 kilometers of myelinated fibers are lost. This means that the brain ages 3.6 years every hour a stroke occurs without treatment. Even after a patient is administered to a hospital and the blockage is removed, surviving neurons can be very stressed from the period of oxygen and glucose starvation. Therefore, NeuroTrojan will be most effective for patients who are being treated within a few hours after their stroke. In speaking with several clinical doctors and researchers, they agreed that NeuroTrojan’s methodology could be adopted for other types of neurodegenerative diseases like Alzheimer’s and Parkinson’s, where it is difficult to access neurons. The Trojan horse therapy could be modified to deliver a different therapeutic protein that is more efficacious for the disease it is treating.
In pivotal clinical trials for aducanumab for treatment of Alzheimer's disease, only 0.6% of clinical study participants were black. When designing a therapy, it is important to consider how it affects different racial demographics and how it can be made accessible to underserved communities. Pivotal trials for many new drugs fail to include participants who identify as members of a historically marginalized racial and ethnic group. After our meeting with Dr. Julia Barrett, she sent us an article regarding new federal incentives for diversity in clinical trials. Notably, in June, the U.S. House of Representatives passed legislation to increase diversity of populatiions enrolled in clinical trials. Current barriers in representativeness of clinical trials include restrictive eligibility criteria, costs associated with participation, limited enrollment outreach in marginalized racial and ethnic communities and in safety-net facilities, implicit English-language requirements, and systemic inequities in access to care. While our therapy may not be able to fully address the systemic inequalities that exist in American healthcare, we do believe that our team should perform phase 2 and 3 clinical trials in hospitals within diverse communities. This is especially important considering that Black Americans are the most vulnerable population segment for stroke; Black Americans have a higher prevalence of stroke and highest death rate from stroke than any other racial group.
Our team wanted to confirm that NeuroTrojan would be not just effective, but also safe. After doing research on the benefits of NT-3 and FGF-2 on in-vitro models of neurons, we assumed that they would be safe as therapeutic proteins. However, a meeting with Dr. Karamyan changed our mind. Dr. Karamyan mentioned that he had previously read that Nerve Growth Factor (NGF), was involved in chronic pain in clinical studies of patients. We read more literature online and found that increased levels of NGF are found in osteoarthritis, low back pain, and interstitial cystitis. Administration of NGF resulted in hyperalgesia, or high sensitivity to pain. NGF and NT-3 are both in the same protein family of neurotrophins, and both proteins are structurally similar. Thus, it is likely that administration of NT-3 to neurons in the brain will result in hyperalgesia as a side effect. When we brought this up to experts who work with or in the FDA, they mentioned that some growth factor proteins were already approved for treatment by the FDA, and only through early clinical trials could the safety of our therapy be elucidated.
If our team wanted to implement NeuroTrojan as an effective therapeutic within the United States, we would have to interact with the Federal Drug Administration (FDA). In meeting with Mr. O’Neill at Xylyx Bio, we gained some understanding of how our therapy could be approved by the FDA. While we currently have data that verifies our Trojan horse’s ability to cross the Blood-Brain Barrier and its ability to interact with the cell receptor, we would still need to prepare data that shows that NeuroTrojan can promote neuroprotection on an in-vitro neuronal model. To pass phase 1 of clinical trials, we would also need to perform toxicity testing on animal models to determine the concentration of treatment that promotes neuroprotection in animals without too many negative side effects. Within phase 2 of clinical trials, our therapy would test for the appropriate dose for optimal therapeutic benefit. If our therapy passes this stage, it would enter phase 3, where NeuroTrojan would be administered on a larger cohort of stroke patients.
If NeuroTrojan were to show success in phase 1 and 2 clinical trials, we would have to scale up production for phase 3 trials and after that, for distribution in the real world. Because our team would not have the resources by ourselves to manufacture our therapeutic at te necessary demand, we would outsource this task to another firm with the ability to do so. We discussed with Dr. William Tanner this kind of symbiotic relationship between smaller and larger biotech companies. Through further research, we found that a larger, well-established partner could provide the sales and marketing power to make our therapy more accessible. In addition, this partner could manufacture our fusion protein therapy at a scale much larger than our team is capable of. Because bacteria cells that are typically used for protein synthesis, like E. coli, cannot correctly fold monoclonal antibodies like HIRMAb, our manufacturing partner would be able to transfect and produce our fusion proteins on a much larger scale. This partner would also have the space to freeze down and store our fusion protein to prevent it from degrading.