DELIVERY - Cyclosporine | TBI’s Miracle Drug

Steve Campbell

First discovered by Sandoz (now Novartis) scientists in Norway in 1969, cyclosporine is isolated from the fungus Tolypocladium inflatum.

An accidental discovery about 20 years ago has led to a cyclosporine pharmaceutical on the threshold of approval

Often called the silent epidemic, traumatic brain injury (TBI) afflicts approximately 1.7 million Americans annually. More than 52,000 are killed, and 275,000 are hospitalized.¹ Most are left in various states of disability—from almost full recovery to mild symptoms but able to function with some or moderate disability to severe disability requiring around-the-clock intensive care and support. The annual costs of TBI, both direct and indirect, including such factors as lost work time or reduced productivity, have been estimated at more than $60 billion, and there may be more than six million TBI survivors in society.
Over the past decade, TBI has come to the fore as tens of thousands of wounded soldiers return home from the Middle East suffering both hidden and visible TBIs and trauma caused by blast injuries from improvised roadside explosions.²
What is called post-traumatic stress disorder may actually be the long-term effects of TBI.
Due to the economic and social costs of TBI, a significant ongoing effort is being made to develop and apply emerging new clinical and pre-clinical pharmaceuticals with the potential to mitigate the cascading additional brain damage that occurs during the critical secondary phase in TBI. Among these is an interesting pharmaceutical compound called cyclosporine (also known as cyclosporin-A, or CsA), which has been found to have significant neuroprotective capabilities and the ability to moderate the resulting damage and long-term disability in TBI.^3-6
Pre-clinical mouse model studies show an 80% reduction in neural damage after the application of this pharmaceutical.^7-8 More than 17 years in development for neuroprotection, CsA is working its way toward approval as a treatment that can greatly ameliorate the effects of TBI in humans.
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Cyclosporine Mitigates Heart Attacks

Mitochondria are present and produce effective energy in almost all cells in the body. It turns out that mitochondrial collapse may be associated with a variety of acute injuries, such as myocardial infarctions and chronic diseases like amyotrophic lateral sclerosis, multiple sclerosis, and other neurological disorders. In myocardial infarctions, reperfusion of the blocked artery can cause reperfusion injury and extra damage and disability to the heart muscle, as well as increased mortality. Mitochondrial protection in heart muscle tissue is one answer to moderating the long-term impact of heart attacks on health and lifestyle.
Every year, an estimated 500,000 people in the United States suffer a myocardial infarction. Infarct size is a major determinant of mortality. During myocardial reperfusion, the abruptness of the reperfusion can cause additional damage—a phenomenon called myocardial reperfusion injury. Studies indicate that this form of injury can account for up to 50% of the final size of the infarct.¹ Focusing on reducing the additional infarct resulting from reperfusion would protect heart muscle and allow the patient to live longer and in better health after the initial attack.
Interestingly, a number of proposed interventions, such as ischemic postconditioning, have been claimed to mediate cardioprotective actions by acting on the opening of the mitochondrial permeability transition pore (MPT), which is directly inhibited by cyclosporine. CsA has been studied for its cardioprotective capabilities and found to be a potentially significant pharmaceutical for ameliorating long-term damage from heart attacks.
A small proof-of-concept clinical study by Christophe Piot, MD, PhD, and his colleagues, published in The New England Journal of Medicine in 2008, found that the administration of CsA with the aim of inhibiting the induction of the MPT was associated with a 40% reduction in infarct size.² An editorial in the journal called for large, multi-center studies to determine if this new treatment option can positively influence clinical outcomes. In addition, targeting the MPT “may also offer protection in other clinical contexts, such as stroke, cardiac surgery, and organ transplantation.”
Following that lead, in April, a European investigator-initiated multi-center phase III study of NeuroVive’s cyclosporine-based cardioprotection pharmaceutical CicloMulsion in myocardial infarctions enrolled the first of 1,000 patients.³ —SC

References

1. Hausenloy DJ, Yellon DM. Time to take myocardial perfusion injury seriously. N Engl J Med. 2008;359(5):518-520.
2. Piot C, Croisille P, Staat P, et al. Effect of cyclosporine on reperfusion injury in acute myocardial infarction. N Engl J Med. 2008; 359(5):473-481.
3. AktieTorget. NeuroVive: first heart attack patient treated in European cardioprotection phase III trial with NeuroVive’s Ciclomulsion. AktieTorget website. Available at: www.aktietorget.se/NewsItem.aspx?ID=58252. Accessed Aug. 12, 2011.

Two Stages

Cyclosporine is a cyclic peptide of 11 amino acids and contains a single D-amino acid, rarely encountered in nature. Cyclosporine protects mitochondria in TBI, myocardial infarction and other acute injury applications.

TBI has two stages. The first stage occurs at the time of injury, whether it is caused by a gunshot, blast, fall, or hit. This initial stage could be either a closed-head or open wound, and medical emergency personnel focus on treating the wound or injury and stabilizing the patient’s vital signs.
The secondary stage of damage to the brain takes place after the initial insult, as the injury continues to ripen and worsen in the hours and days after the initial trauma. This is when the doctor says, “Now we just wait and see,” because there’s nothing more that medicine can do. In this secondary stage, the trauma to the brain triggers a series of cascading intra-cellular biochemical reactions that cause severe demise of brain cells, brain damage, and expanded disability. If this secondary stage can be mitigated, the potential damage and disability can be reduced significantly, enabling the victim to get closer to full recovery.
Some of the secondary-stage mechanisms believed by researchers to be involved in brain-cell death after TBI include uncontrolled release of signalling molecules (neurotransmitters), cellular calcium overload, inflammation, energy failure, oxidative damage, and the overactivation of enzymes such as calpains and caspases.⁹
All of these are believed to create the intra- and extra-cellular conditions that lead to the destruction of millions of additional brain cells, along with the damage and disability that result. Many of these are being targeted by a variety of pharmaceutical compounds and medical treatments that are in various stages of clinical development—including forcing oxygen into the brain through the use of hyperbaric chambers. Because it targets the protection of mitochondria inside brain cells, cyclosporine is perhaps the most promising of these.
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Pharmaceutical Approaches to TBI

There are a number of TBI pharmaceuticals in a variety of stages of development. The most promising of these approaches are “multipotential,” targeting at least two secondary-stage injury mechanisms, including excitotoxicity, apoptosis, inflammation, edema, blood– brain barrier disruption, oxidative stress, mitochondrial disruption, calpain activation, and cathepsin activation.¹
The value of multipotential agents is their potential to modulate one or more of these multiple secondary injury factors, greatly increasing the chance of achieving clinical value. Previously, more than 30 phase III clinical studies for single-factor targeted TBI pharmaceuticals failed to find significance. Multipotential agents may have a better chance of delivering a successful therapeutic result for TBI patients and, ultimately, recouping the costs of development and trials.
Promising pharmacological multipotential agents fall into two categories: those that have been studied clinically and those that constitute emerging pre-clinical strategies.
Clinically studied pharmaceuticals include the statins (targeting excitotoxicity, apoptosis, inflammation, edema), progesterone (excitotoxicity, apoptosis, inflammation, edema, oxidative stress), and cyclosporine (mitochondrial disruption, calpain activation, apoptosis, oxidative stress).
Emerging multipotential neuroprotective agents showing promise in pre-clinical studies include diketopiperazines (apoptosis, calpain activation, cathepsin activation, inflammation), substance P antagonists (inflammation, blood–brain barrier, edema), SUR1-regulated NC channel inhibitors (apoptosis, edema, secondary hemorrhage, inflammation), cell cycle inhibitors (apoptosis, inflammation), and PARP inhibitors (apoptosis, inflammation). —SC

Reference

1. Loane DJ, Faden AI. Neuroprotection for traumatic brain injury: translational challenges and emerging therapeutic strategies. Trends Pharmacol Sci. 2010;31(12):596–604.

Role of Mitochondria

Stick model of cyclosporine, as found in the P2₁2₁2₁ crystalline form, demonstrates the complexity of this peptide.

Research confirms that mitochondria, the cellular energy (adenosine triphosphate, or ATP) producers inside the brain cells, play a pivotal role in neuronal cell death or survival, and that mitochondrial dysfunction in brain injuries is considered an early event that causes neuronal cell death. The uncontrolled release of signalling molecules with resulting overstimulation/stress of brain cells and accumulation of high levels of intracellular calcium may be the initial mechanism that leads to neuronal cell death.¹⁰
How does this affect brain cells? Increases in calcium lead to its rapid uptake into the mitochondria, which act as cellular sinks for calcium. However, the excessive transport and uptake of calcium negatively impacts mitochondrial energy production, because the driving force for both ATP production and calcium transport relies on the “proton motive force” (the proton gradient created over the mitochondrial inner membrane by the respiratory chain). Further, excessive calcium uptake by mitochondria, in combination with energy failure, leads to the formation of protein channels (pores) in the inner membrane—the induction of the so-called mitochondrial permeability transition (MPT).
The increased permeability of the inner membrane caused by the MPT pores immediately collapses mitochondrial function and structure, because when the pores are opened, the osmotically active inner compartment (matrix) of the mitochondria attracts water, and the mitochondria swell and pop like balloons. In addition to causing the cessation of energy production, upon induction of the MPT, the stored calcium and harmful proteins are then released from mitochondria, resulting in an avalanche of further mitochondrial collapse, cellular energy depletion, and subsequent cell death. When brain cell death is repeated millions of times during the cascading biochemical imbalances that characterize the secondary phase, the extent of brain damage and eventual disability are greatly increased.
Protecting the mitochondria by targeting the MPT is a viable neuroprotective approach that has emerged in the last decade. Published research has found that the protein cyclophilin D is an essential component to opening the MPT pores and that cyclosporine binds to cyclophilin D and inhibits the induction of MPT.^11,12 The result is that mitochondria can absorb much more calcium without collapsing, allowing them to survive. As mitochondria survive to produce energy for brain cells, fewer brain cells die during the secondary stage. This is the core battleground in the war against TBI.
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What is TBI?

CRUSHED: After the initial brain injury, excessive calcium imbalances during the all-important secondary damage phase cause brain cell mitochondria to swell and burst, releasing calcium that creates a cascading avalanche of further mitochondrial collapse, cellular energy depletion, and subsequent brain cell death. By protecting mitochondria, cyclosporine limits overall brain damage and eventual disability.

BRUISED: Limiting the secondary stage brain damage that occurs after the initial injury is a key strategy in treating TBIs. Cyclosporine does this by protecting the brain cell mitochondria from collapse during the secondary stage, enabling non-injured brain cells to continue energy production and operation while recovery from the initial injury occurs.

A traumatic brain injury is defined as a blow or jolt to the head or a penetrating head injury that disrupts the function of the brain. Not all blows to the head result in a TBI. The severity of a TBI may range from “mild,” involving a brief change in consciousness, to “severe,” featuring an extended period of amnesia or unconsciousness. A TBI can result in problems with independent function, either short- or long-term.
Millions of Americans have a long-term need for help in performing their daily activities as a result of suffering a TBI. By one estimate, there are up to 6 million survivors of TBI. Statistics on the full extent of TBI are not known, however, because the number of people with TBI who were not seen in an emergency department and/or who have received no formal care cannot be determined.
The leading causes of TBI include falls, car crashes, hitting or being hit in sports, and physical assault. In war zones, blasts from roadside improvised explosive devices (IEDs) and other explosions are a leading cause of TBI for soldiers. Males are 1.5 times as likely as females to suffer a TBI, and the two age groups at highest risk are children aged 0–4 years and teenagers aged 15–19. African Americans have the highest death rates from TBI, and it is the fourth-leading cause of death for males under age 45.¹
More recently, the Iraq and Afghanistan wars have brought the issue to the attention of the public and Congress, as advances in combat protection and helmets have allowed soldiers to survive blasts that would previously have killed them.
Post injury, there is little that can be done for soldiers returning home with TBI. It’s been estimated that some 200,000 returning soldiers have varying degrees of TBI, ranging from mild to severe. Symptoms include depression, an inability to concentrate, moodiness, and frustration as the TBI sufferer struggles to complete formerly routine tasks. Moreover, much anti-social behavior exhibited in society may be related to diagnosed and undiagnosed traumatic brain injuries sustained in battle, on sports fields, on the streets, or around the home. —SC

Reference

1. U.S. Centers for Disease Control and Prevention (CDC). National Center for Injury Prevention and Control. Injury prevention and control: traumatic brain injury. CDC website. Available at: www.cdc.gov/traumaticbraininjury/statistics.html. Accessed Aug. 12, 2011.

Cyclosporine Protects

Cyclosporine protects brain cells by preventing the cascading biochemical imbalances of the TBI from causing the mitochondria to collapse and stop powering the brain cells, exacerbating brain damage and leading to disability.

Cyclosporine was discovered in 1969 when it was first isolated from the fungus Tolypcladium inflatum in Norway by researchers working for Sandoz (now Novartis). Its impressive immunosuppressive properties led to its use as a pharmaceutical to prevent tissue rejection in organ transplant recipients. It has been in use for immunosuppressive applications since the early 1980s as a commercially successful Novartis product called Sandimmune.¹³
CsA’s ability to protect the mitochondria in the brain by binding to cyclophilin D and preventing the induction of the MPT was discovered in 1993–1994, a period during which medical researcher Eskil Elmér, MD, PhD, and his Japanese colleague Hiroyuki Uchino, MD, PhD, were conducting experiments in cell transplantation. An unintended finding was that CsA was strongly neuroprotective when it crossed the blood–brain barrier.¹⁴ This startling discovery became the starting point for basic research and patent applications in a promising new avenue of neuroprotection.
Basic research mapping out CsA’s extensive neuroprotective capabilities has been running continuously since 1993, and many international and independent research teams have since conducted and published numerous studies confirming that CsA is a powerful nerve-cell protector in TBI, stroke, and brain damage associated with cardiac arrest. Advanced studies also show that CsA is useful in protecting mitochondria in heart tissue facing reperfusion injury during heart attacks (see sidebar).¹⁵
Together with U.S. neurosurgeon Marcus Keep, MD, Dr. Elmér and his colleagues formed a company with the aim of commercializing and patenting their work of developing cyclosporine-based products for acute conditions and diseases affecting the brain. In 1999, the U.S. patent was approved and, in 2000, their CsA product name, NeuroSTAT, was registered. Later, the patent portfolio around CsA’s impact on the central nervous system and other areas was expanded greatly under their company, NeuroVive Pharmaceutical AB (Sweden).

Cyclosporine acts to protect the brain cell’s mitochondria from the cascading biochemical imbalances that cause these cellular power sources to collapse and stop powering millions of brain cells. This reduces the additional brain damage and disability that occurs during the secondary damage phase of TBI.

Today, NeuroVive’s NeuroSTAT version of cyclosporine is a fully developed product. An important advancement in NeuroSTAT is that its formulation is made using a patented non-allergenic lipid emulsion to keep CsA a lipophilic drug in solution.

Next Steps

It’s been almost two decades since Dr. Elmér and his colleagues discovered cyclosporine’s neuroprotective capabilities, and there is still some way to go. However, CsA’s promise as a TBI pharmaceutical continues to make progress. Full commercialization is in sight.
In 2010, NeuroSTAT received orphan drug status from both the U.S. Food and Drug Administration and its European counterpart for the treatment of moderate and severe TBI. In March, the company announced it would be working with the European Brain Injury Consortium to conduct a phase II/III adaptive study on NeuroSTAT.¹⁶ These clinical trials should provide the basis for the registration of NeuroSTAT in Europe, and possibly in the U.S. and other countries. U.S.-based clinical trials are also being planned, and NeuroVive is seeking partnering organizations in China for similar trials. Of course, the challenges in such development, where many drugs have failed in the past, involve translating the research results into clinical benefits in patients and recruiting a sufficient number of patients within a reasonable time. 

Cyclosporine is isolated from the fungus Tolypocladium inflatum. In the early 1990s, NeuroVive’s chief scientific officer Eskil Elmér and his Japanese colleague Hiroyuki Uchino discovered cyclosporine was strongly neuroprotective when it crossed the blood–brain barrier.

Assuming all goes according to plan, cyclosporine’s early promise from its serendipitous discovery as a neuroprotectant in the 1990s could be fulfilled within the next two to five years. And neurologists and neurosurgeons worldwide will finally be able to trumpet an exciting new weapon in the war against the silent epidemic of traumatic brain injuries.

References

1. U.S. Centers for Disease Control and Prevention (CDC). National Center for Injury Prevention and Control. Injury prevention and control: traumatic brain injury. CDC website. Available at: www.cdc.gov/traumaticbraininjury/statistics.html. Accessed Aug. 12, 2011.
2. Hoge CW, McGurk D, Thomas JL, et al. Mild traumatic brain injury in U.S. soldiers returning from Iraq. New Engl J Med. 2008;358(5):453-463.
3. Sullivan PG, Sebastian AH, Hall ED. Therapeutic window analysis of the neuroprotective effects of cyclosporine A after traumatic brain injury. J Neurotrauma. 2011;28(2):311-318.