Why Scientists Believe Theyve Made New Breakthrough In Parkinsons Disease Treatment By Building On Gdnf Research
The Finnish researchers are now working to improve the properties of BT13 to make it more effective as a potential treatment that could benefit many people living with the disease.
The study, which was published online yesterday in the journal Movement Disorders, builds on previous research on another molecule that targets the same receptors in the brain.
GDNF – or glial cell line-derived neurotrophic factor – is an experimental treatment for Parkinson’s discovered in 1993 that has been shown to bring dying brain cells back to life and particularly effective in dopamine neurons.
It was the subject of a BBC documentary in February 2019 that followed a phase two trial in Bristol involving 42 patients. While the results weren’t clear cut, GDNF has shown promise to restore damaged cells in people with Parkinson’s.
However, the GDNF protein requires complex robot-assisted surgery to deliver the treatment to the brain because it’s a large molecule that can’t cross the blood-brain barrier – a protective wall that prevents some drugs from getting into the brain.
BT13 is a smaller molecule that is able to cross the blood-brain barrier – and therefore could be more easily administered as a treatment if shown to be beneficial in further clinical trials.
Dr Yulia Sidorova, lead researcher on the study, said: “We are constantly working on improving the effectiveness of BT13.
“Our ultimate goal is to progress these compounds to clinical trials in a few coming years.”
Related Article
New Study Gives Clue To The Cause And Possible Treatment Of Parkinson’s Disease
Zebrafish model research reveals clues about molecular triggers of Parkinson’s Disease
Niigata University
image: Immunostaining: Top panel SH-SY5Y cells transfected with GBA, ATP13A2, and PINK1 siRNAs are stained for dsDNA , histone H2B and Hsp60 . White arrows indicate cytosolic dsDNA of mitochondrial origin. Triple siRNA: Knockdown of GBA, ATP13A2, and PINK1 expression with siRNAs. Coimmunostaining: Bottom panel In situ hybridization of mitochondrial DNA and coimmunostaining for histone H2B and Hsp60 in SH-SY5Y cells transfected with GBA, ATP13A2, and PINK1 siRNAs. White arrows indicate cytosolic dsDNA of mitochondrial origin. Triple siRNA: Knockdown of GBA, ATP13A2, and PINK1 expression with siRNAs.view more
Niigata, Japan – Researchers from Brain Research Institute, Niigata University, Japan may have unraveled a new approach that could revolutionize the treatment, prevention, and possibly reversal of the damages that could lead to Parkinson’s Disease . This novel finding utilizing the cellular and zebrafish models, demonstrated how the leakage of mitochondrial dsDNA into the cytosol environment of the cell can contribute to the impairment of brain tissue of patients with PD.
Parkinson’s disease is the second most common neurodegenerative disease, and its prevalence has been projected to double over the next 30 years.
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Journal
DOI
10.1038/s41467-021-23452-x
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What Should I Think About Before Participating In A Clinical Study
Talk to your doctor first. Sometimes you may find out about research from the internet or an advertisement. Talk to a doctor you trust before you agree to participate.
Look for research studied conducted by a reputable institution. The Parkinson’s Foundation’s Centers of Excellence and other top academic medical centers are trustworthy institutions that have rules in place related to the protection of human research subjects. If you are recruited for a clinical trial by your local doctor, look up the trial on ClinicalTrials.gov. If the doctor leading the trial is not affiliated with a reputable university or major research hospital and the trial is not listed in ClinicalTrials.gov, be careful and do your research.
Read the consent form carefully. It is important that no one forces you to participate. Before you sign up, you will be part of the informed consent process. The consent form should be written in a language you understand. The researchers should explain the risks and benefits of the study. Ask questions if something is confusing or unclear. Take time to understand what you are signing up for. Understand your rights if you agree to participate now, but wish to withdraw later.
Young Onset Parkinsons Research Results In Interesting Findings
Recent press coverage has highlighted some interesting outcomes from studies of stem cells derived from people diagnosed with Young Onset Parkinson’s. This group is generally defined as those being diagnosed between the ages of 21 and 50.
The researchers at Cedars- Sinai Medical Centre , USA, generated special stem cells from blood taken from young onset people with Parkinson’s who have no family history of the condition. The process of generating these stem cells involves taking the blood cells ‘back in time ‘to a primitive embryonic state before they could be transformed into dopamine neurons in the lab. The dopamine neurons were then observed to have two key abnormalities:
- The protein associated with Parkinson’s – alpha- synuclein was seen to accumulate
- Lysosomes or cell structures which act as clearance or ‘trash cans’ for the cells to dispose of proteins were seen to malfunction- this could cause the alpha- synuclein to build up.
The researchers suggest that this is a sign that young onset Parkinson’s is present from conception or as the popular press suggests “starts in the womb”.
In addition to this discovery the team at Cedars- Sinai are working on these iPSCs to test a number of drugs which may reverse the abnormalities they found. This is an exciting outcome to the study.
Determining Diagnosis Through Response To Parkinsons Medication
If a person’s symptoms and neurologic examination are only suggestive of Parkinson’s disease or if the diagnosis is otherwise in doubt, the physician may, nevertheless, prescribe a medication intended for Parkinson’s disease to provide additional information. In the case of idiopathic Parkinson’s, there is typically a positive, predictable response to Parkinson’s disease medication; in the case of some related Parkinsonian syndromes, the response to medication may not be particularly robust, or it may be absent entirely.
Unfortunately, there are no standard biological tests for the disease, such as a blood test. However, researchers are actively trying to find biomarkers in blood and other bodily fluids that could help confirm the diagnosis.
Current Parkinsons Treatments Cant Slow Down Onset Of Disease
Parkinson’s is a long-term degenerative disorder of the central nervous system, which mainly the area of the brain that controls movement – leading to a slow onset of symptoms including tremors, rigidity and slow movement.
More than 10 million people worldwide are estimated to be living with Parkinson’s disease, according to the US-based Parkinson’s Foundation, with the Parkinson’s News Today website saying it affects 1,900 per 100,000 among those aged over 80,
Typically, by the time people are diagnosed with the condition, they have already lost between 70% and 80% of their dopamine-producing cells, which are involved in co-ordinating movement.
While current treatments mask the symptoms, there is nothing that can slow down its progression or prevent more brain cells from being lost.
As dopamine levels continue to fall, symptoms get worse and new symptoms can appear.
Brain Imaging And Other Tools To Aid Diagnosis Of Parkinsons
In addition to taking a history and performing a detailed neurologic examination, physicians sometimes use brain imaging to help support a particular diagnosis. However, these studies have their limitations in the diagnosis of Parkinson’s disease and are typically used only in select patients. Brain imaging is not routinely performed by neurologists or movement disorder specialists when they are considering a diagnosis, especially if the person’s symptoms strongly suggest to the physician that idiopathic Parkinson’s disease is the correct diagnosis.
Helping diagnose Parkinson’s with DaTscan and other tests
Rather, use of imaging is most helpful when the diagnosis is uncertain, or when physicians are looking for changes in the brain that are more typical of one of several Parkinsonian syndromes and other conditions that can mimic Parkinson’s. Imaging studies to evaluate Parkinson’s disease and Parkinsonian syndromes include magnetic resonance imaging , which examines the structure of the brain, and DaTscan, an imaging test approved by the Food and Drug Administration to detect the dopamine function in the brain. A DaTscan may help differentiate idiopathic Parkinson’s disease from certain other neurologic disorders. Most physicians’ offices will have access to MRI; however, DaTscan imaging may only be available at larger hospitals or medical centers.
What Diseases And Conditions Resemble Parkinsons Disease
PD is the most common form of parkinsonism, in which disorders of other causes produce features and symptoms that closely resemble Parkinson’s disease. Many disorders can cause symptoms similar to those of PD, including:
Several diseases, including MSA, CBD, and PSP, are sometimes referred to as “Parkinson’s-plus” diseases because they have the symptoms of PD plus additional features.
In very rare cases, parkinsonian symptoms may appear in people before the age of 20. This condition is called juvenile parkinsonism. It often begins with dystonia and bradykinesia, and the symptoms often improve with levodopa medication.
Keen Sense Of Smell Leads To First Test For Parkinsons
Earlier diagnosis of Parkinson’s before physical symptoms appear is becoming a reality, with latest clinical trials looking at smell as a possible indicator of Parkinson’s.
Please click here to read article published in leapsmag: https://leapsmag.com/her-incredible-sense-of-smell-led-scientists-to-develop-the-worlds-first-test-for-parkinsons/
Can Scientists Predict Or Prevent Parkinson’s Disease
In most cases, there is no way to predict or prevent sporadic Parkinson’s disease. However, researchers are looking for a biomarker— a biochemical abnormality that all patients with Parkinson’s disease might share — that could be picked up by screening techniques or by a simple chemical test given to people who do not have any parkinsonian symptoms. This could help doctors identify people at risk of the disease. It also might allow them to find treatments that will stop the disease process in the early stages.
Positron emission tomography scanning may lead to important advances in our knowledge about Parkinson’s disease. PET scans of the brain produce pictures of chemical changes as they occur. Using PET, research scientists can study the brain’s dopamine receptors to determine if the loss of dopamine activity follows or precedes degeneration of the neurons that make this chemical. This information could help scientists better understand the disease process and may potentially lead to improved treatments.
In rare cases, where people have a clearly inherited form of Parkinson’s disease, researchers can test for known gene mutations as a way of determining an individual’s risk of the disease. However, this genetic testing can have far-reaching implications and people should carefully consider whether they want to know the results of such tests. Genetic testing is currently available only as a part of research studies.
Australian Parkinsons Research Receives $30 Million
Australian Parkinson’s research is receiving $30 million in Federal Government Funding. Federal Minister for Health, The Hon. Greg Hunt MP, will enable the Australian Parkinson’s Mission to identify desperately needed modifying drugs with the potential to slow the progression of Parkinson’s.
CURTIN RESEARCH LATEST NEWS
Parkinson’s WA has awarded Parkinson’s Centre scientists a $70k Zrinski Research Grant to identify subtypes of Parkinson’s in a first-of-its-kind study to help improve quality of life.
Using sophisticated analysis of data collected over a number of years, researchers will identify groups of people based on the pattern of their thinking skills.
Research Director, Dr Andrea Loftus, said the team would examine how participants differ in terms of their quality of life, sleep, and mood.
“Using this information, we will conduct research into how the different subtypes respond to interventions such as non-invasive brain stimulation and cognitive training,” Dr Loftus said.
“It may be that a particular group, for example, those who have difficulties with planning, respond better to cognitive training or brain stimulation than others.
“Parkinson’s is an umbrella term which we think encompasses a range of different symptom groups. It is clear that no one person’s Parkinson’s is the same as another’s, but there are some characteristics which some people have in common.
Brains Behind Best Parkinson’s Treatment
What Research Is Being Done On Parkinson’s Disease
In recent years, Parkinson’s research has advanced to the point that halting the progression of Parkinson’s disease, restoring lost function, and even preventing the disease are all considered realistic goals. While the ultimate goal of preventing Parkinson’s disease may take years to achieve, researchers are making great progress in understanding and treating Parkinson’s disease.
One of the most exciting areas of Parkinson’s disease research is genetics. Studying the genes responsible for inherited cases can help researchers understand both inherited and sporadic cases of the disease. Identifying gene defects can also help researchers understand how Parkinson’s disease occurs, develop animal models that accurately mimic the neuronal death in human Parkinson’s disease, identify new drug targets, and improve diagnosis.
As discussed in the “What Genes are Linked to Parkinson’s Disease?” section, several genes have been definitively linked to Parkinson’s disease in some people. Researchers also have identified a number of other genes that may play a role and are working to confirm these findings. In addition, several chromosomal regions have been linked to Parkinson’s disease in some families. Researchers hope to identify the genes located in these chromosomal regions and to determine which of them may play roles in Parkinson’s disease.
How Could Stem Cells Help People With Parkinson’s
Stem cells are the parent cells of all tissues in the body. This means they can turn into any type of cell. The hope is that they will eventually be able to make these cells into specific types of cells, like dopamine-producing neurons, that can be used to treat Parkinson’s disease. However, there are concerns that patients may have the same risk of increased involuntary movements as those who undergo fetal cell transplantation. And, like fetal cell transplantation, stem cell therapy is surrounded by moral and ethical controversy.
What Are The Risk Factors For Parkinson’s Disease
- Age: The disease ordinarily begins in middle or late life, and the risk continues to increase with age.
- Heredity: Having a close relative with the condition increases the chances that you’ll also develop the disease; however, your risksare still small unless you have many relatives in your family with the condition.
- Sex: Men are more likely to develop the disease than women.
- Exposuretotoxins: Ongoing exposure to herbicides and pesticides may put you at a slightly increased risk.
Types Of Medications To Treat Parkinsons Disease
Medications in the research pipeline can be divided into two main categories: those that treat the symptoms of PD and those that are disease modifying . Of note, all medications currently available for PD are symptomatic treatments. There is no medication at this time that can affect the progression of the disease. Of course, the PD research community is extremely eager to find a medication that is disease modifying or neuroprotective . There have been many attempts over the past number of years to demonstrate through clinical trials that particular compounds have neuroprotective effects but, to date, these attempts have not been successful.
If you are interested in getting involved in a clinical trial, Clinicaltrials.gov is a database of all clinical trials for all diseases worldwide. When a clinical trial is registered with the site, it is assigned a unique number called the National Clinical Trial number or NCT number. Where available, I will provide the NCT number for each clinical trial that I reference in case you are interested in learning more.
More Ways To Get Involved In Parkinsons Research
The Parkinson’s UK Research Support Network provides the latest news, events and opportunities to take part and shape research.
Parkinson’s Movement is an initiative of The Cure Parkinson’s Trust which aims to inform and encourage people to read about, participate in or contribute to Parkinson’s research.
Six facts about Parkinson’s Disease:
For more information about Parkinson’s Disease, visit the Parkinson’s UK website.
What Is The Prognosis For Parkinson’s Disease
Parkinson’s disease is not by itself a fatal disease, but it does get worse with time. The average life expectancy of a Parkinson’s disease patient is generally the same as for people who do not have the disease. However, in the late stages of the disease, Parkinson’s disease may cause complications such as choking, pneumonia, and falls that can lead to death. Fortunately, there are many treatment options available for people with Parkinson’s disease.
The progression of symptoms in Parkinson’s disease may take 20 years or more. In some people, however, the disease progresses more quickly. There is no way to predict what course the disease will take for an individual person. One commonly used system for describing how the symptoms of Parkinson’s disease progress is called the Hoehn and Yahr scale.
Hoehn and Yahr Staging of Parkinson’s Disease
Stage one
- Symptoms on one side of the body only.
Stage two
- Symptoms on both sides of the body. No impairment of balance.
Stage three
- Balance impairment. Mild to moderate disease. Physically independent.
Stage four
- Severe disability, but still able to walk or stand unassisted.
Stage five
- Wheelchair-bound or bedridden unless assisted.
With appropriate treatment, most people with Parkinson’s disease can live productive lives for many years after diagnosis.
Advanced And Future Treatments For Parkinsons
Graham Rogers, M.D.Kimberly Holland
While there’s no cure for Parkinson’s disease, recent research has led to improved treatments.
Scientists and doctors are working together to find a treatment or prevention technique. Research is also seeking to understand who is more likely to develop the disease. In addition, scientists are studying the genetic and environmental factors that increase the chance of a diagnosis.
Here are the latest treatments for this progressive neurological disorder.
In 2002, the FDA approved deep brain stimulation as a treatment for Parkinson’s disease. But advances in DBS were limited because only one company was approved to make the device used for the treatment.
In June 2015, the FDA approved the
What Kinds Of Genetic Research Is Being Done
Researchers are investigating genes that code proteins responsible for producing dopamine. By increasing the amount of dopamine in the brain, Parkinson’s symptoms can be minimized if not prevented.
What other treatments are being researched?
- Drug treatments. Researchers are investigating drugs that block the action of glutamate, an amino acid that destroys nerve cells, as well as the role of the antioxidant coenzyme Q-10 in slowing the progression of Parkinson’s disease.
- Neural growth factor. Preliminary studies have shown that neural growth factor revives the dormant cells needed to produce dopamine, dramatically improving symptoms.
- Deep brain stimulation. Research is underway to better understand how deep brain stimulation works in Parkinson’s disease. Researchers are also studying improved ways of stimulating the brain.
How Can People Cope With Parkinson’s Disease
While PD usually progresses slowly, eventually daily routines may be affected—from socializing with friends to earning a living and taking care of a home. These changes can be difficult to accept. Support groups can help people cope with the disease’s emotional impact. These groups also can provide valuable information, advice, and experience to help people with PD, their families, and their caregivers deal with a wide range of issues, including locating doctors familiar with the disease and coping with physical limitations. A list of national organizations that can help people locate support groups in their communities appears at the end of this information. Individual or family counseling may also help people find ways to cope with PD.
People with PD may also benefit from being proactive and finding out as much as possible about the disease in order to alleviate fear of the unknown and to take a positive role in maintaining their health. Many people with PD continue to work either full- or part-time, although they may need to adjust their schedule and working environment to accommodate their symptoms.
Why Should I Participate In A Clinical Study
We can only reach breakthroughs in treatment and care if people participate in the studies.
Participating is safe and can help you.
Every clinical study is reviewed thoroughly before your doctor asks you to participate. Clinical trials carry some risks, but your doctor is required by law to explain the risks to you clearly and make sure that you understand them. If your doctor tells you about the risks of participating in the study, ask yourself, “What are the risks of not participating in the study?” Most of the time, if you balance the possible benefits from participating against the risks, it is about the same as the risks of not being in the study.
On the other hand, the study may be of a new drug or treatment that could help you. If you don’t participate, it may be years before you have a chance to try that drug.
Some people do not participate because there is no guarantee they will get the experimental therapy; they might get the placebo. Again, think carefully about the risks and benefits of entering the study and getting the new treatment, entering the study and getting the placebo or not entering the study at all.
Your participation can help others
If you have PD or any other disease, the drugs, procedures and therapies you use now were scientifically tested, likely by thousands of volunteers. Participating in a clinical trial is your way to pay it forward for people diagnosed with Parkinson’s in the future.
What Genes Are Linked To Parkinson’s Disease
Several genes have now been definitively linked to Parkinson’s disease. The first to be identified was alpha-synuclein. In the 1990s, researchers at NIH and other institutions studied the genetic profiles of a large Italian family and three Greek families with familial Parkinson’s disease and found that their disease was related to a mutation in this gene. They found a second alpha-synuclein mutation in a German family with Parkinson’s disease. These findings prompted studies of the role of alpha-synuclein in Parkinson’s disease, which led to the discovery that Lewy bodies from people with the sporadic form of Parkinson’s disease contained clumps of alpha-synuclein protein. This discovery revealed a potential link between hereditary and sporadic forms of the disease.
In 2003, researchers studying inherited Parkinson’s disease discovered that the disease in one large family was caused by a triplication of the normal alpha-synuclein gene on one copy of chromosome 4. This triplication caused people in the affected family to produce too much of the normal alpha-synuclein. This study showed that an excess of the normal form of the protein could result in Parkinson’s disease, just as the abnormal form does.
What Are The Symptoms Of Parkinson’s Disease
Early symptoms of Parkinson’s disease are subtle and occur gradually. Affected people may feel mild tremors or have difficulty getting out of a chair. They may notice that they speak too softly or that their handwriting is slow and looks cramped or small. They may lose track of a word or thought, or they may feel tired, irritable, or depressed for no apparent reason. This very early period may last a long time before the more classic and obvious symptoms appear.
Friends or family members may be the first to notice changes in someone with early Parkinson’s disease. They may see that the person’s face lacks expression and animation or that the person does not move an arm or leg normally. They also may notice that the person seems stiff, unsteady, or unusually slow.
As the disease progresses, the shaking or tremor that affects the majority of Parkinson’s patients may begin to interfere with daily activities. Patients may not be able to hold utensils steady or they may find that the shaking makes reading a newspaper difficult. Tremor is usually the symptom that causes people to seek medical help.
People with Parkinson’s disease often develop a so-called parkinsonian gait that includes a tendency to lean forward, small quick steps as if hurrying forward , and reduced swinging of the arms. They also may have trouble initiating movement , and they may stop suddenly as they walk .
Understanding Huntingtons Disease Mechanisms
NINDS-funded researchers are trying to better understand the cellular and molecular mechanisms involved in the neurodegenerative processes of HD by investigating, for instance, how the mutant Huntintin protein affects cell signaling and how its altered structure can contribute to disease. Among research efforts:
- A new avenue of NINDS-supported research is asking whether additional changes to the mutant Huntington gene during development and in adulthood impact disease onset and severity, and whether the mutant Huntington gene affects the brain’s overall ability to maintain healthy, undamaged DNA. This work is a promising area for identifying new modifiers of HD onset and progression that may be attractive drug targets.
- Excessive chemical signaling between cells in the brain may lead to chronic overexcitation , which is toxic to neurons. Several labs are investigating whether drugs that counteract excitotoxicity might help against HD.
- Cutting-edge methods such as optogenetics are being used to probe the cause and progression of cell circuit defects in HD.
What Genes Are Linked To Parkinsons Disease
Several genes have been definitively linked to PD:
- SNCA. This gene, which makes the protein alpha-synuclein, was the first gene identified to be associated with Parkinson’s. Research findings by the National Institutes of Health and other institutions prompted studies of the role of alpha-synuclein in PD, which led to the discovery that Lewy bodies seen in all cases of PD contain clumps of alpha-synuclein. This discovery revealed the link between hereditary and sporadic forms of the disease.
- LRRK2. Mutations in LRRK2 were originally identified in several English and Basque families as a cause of a late-onset PD. Subsequent studies have identified mutations of this gene in other families with PD as well as in a small percentage of people with apparently sporadic PD. LRRK2 mutations are a major cause of PD in North Africa and the Middle East.
- DJ-1. This gene normally helps regulate gene activity and protect cells from oxidative stress and can cause rare, early forms of PD.
- PRKN . The parkin gene is translated into a protein that normally helps cells break down and recycle proteins.
- PINK1. PINK1 codes for a protein active in mitochondria. Mutations in this gene appear to increase susceptibility to cellular stress. PINK1 has been linked to early forms of PD.
- GBA . Mutations in GBA cause Gaucher disease , but different changes in this gene are associated with an increased risk for Parkinson’s disease as well.
How We’re Speeding Up The Search For A Cure
We believe that new and better treatments are possible in years, not decades, and we have a clear strategy for making this happen. This includes:
- backing the best and brightest minds to unlock scientific discoveries that will lead to new treatments and a cure
- accelerating the development and testing of new treatments through our Virtual Biotech
- collaborating internationally to make clinical trials faster, cheaper and more likely to succeed through the Critical Path for Parkinson’s
Drawing & Writing Helping Detect Parkinsons
Drawing and writing may be a new determiner in catching Parkinson’s in its early stages with new technology able to spot the condition before any obvious symptoms appear. When many of the treatment options are beneficial if Parkinson’s is detected early, this pioneering technology may well allow for early intervention, allowing for patients to receive treatment earlier than ever before.
The pioneering technology-refined from a previous version with an accuracy rate of 93% – was developed by Royal Melbourne Institute of Technology and takes into consideration how Parkinson’s impacts muscle control and activities, thereby affecting how patients write and draw.
A screening test involves patients using a drawing tablet to complete seven dexterity tasks, including drawing a spiral by joining dots, simple writing and writing with memory load. Patient tasks are then assessed which can be used to target specific aspects of their condition. The screening technology can also be used to monitor the effectiveness of patient medications and treatment.
Further patient trials are due to commence in both Australia and China in mid 2020 with the technology hopefully commercially available in two years.
What Will A Cure For Parkinson’s Look Like
Because Parkinson’s varies so much from person to person, there may not be a single ‘cure’.
Instead we may need a range of different therapies to meet the needs of the individual and their specific form of the condition.
This mix may include treatments, therapies and strategies that can:
- slow or stop the progression of the condition
- replace or repair lost or damaged brain cells
- control and manage particular symptoms
- diagnose Parkinson’s at the earliest possible stage.
And this could involve medical treatments, such as drugs and surgical approaches, as well as lifestyle changes, for example to diet and exercise.
The Parkinsons Disease Medication Pipeline
The pipeline for Parkinson’s disease medications is extremely crowded these days, with multiple medications at various stages of research development. This is very exciting news for the PD community and is a perfect example of the “hope in progress” part of our organization’s motto. It is thrilling to see the research that is underway, especially the potential treatments that have already made it to the clinical trial phase of development. However, this progress brings with it the welcome challenge of keeping track of all the potential compounds that are in research development! Recently, was published in the Journal of Parkinson’s Disease which cataloged the 145 compounds that are currently being studied in humans via clinical trials for PD. This is a staggering number and is even more exceptional when you consider the many more compounds that are not quite yet ready for human trials, but are currently being studied in the laboratory in test tubes, cell culture or animal models of PD. The number also does not account for compounds that have been studied in small clinical trials, garnered promising data, and will be studied in larger clinical trials in the near future – but are not being tested in clinical trials right now.
Some background on the review