The clinical failure rate of Alzheimer’s drugs is exceptionally high, yet early data from researchers at the Salk Institute suggests marijuana could provide a cure.

The statistics associated with Alzheimer’s disease are downright depressing.

The disease, which typically affects the elderly and is characterized by a progressive decline in cognitive function, currently afflicts 5.4 million Americans, and the Alzheimer’s Association expects the direct and indirect costs of treatment to reach $236 billion in 2016. Some one in nine people over the age of 65 has Alzheimer’s disease, and within the U.S., it’s the sixth-leading cause of death.

These statistics are even scarier when you consider how much researchers still have to learn about this disease. Though there are medications designed to slow the progression of the various stages of the disease, a cure for Alzheimer’s disease remains elusive for the time being.

A number of big-name drug developers have taken aim at Alzheimer’s, only to have their studies end in disappointment. Drug giants Johnson & Johnson and Pfizer teamed up to develop bapineuzumab, while Eli Lilly developed solanezumab. Both drugs missed their primary endpoints in phase 3 studies. It’s difficult to get medicine through the blood-brain barrier, and the clinical success rate of Alzheimer’s drugs is particularly low.

Biogen (NASDAQ:BIIB) is hoping to change that with experimental therapy aducanumab, which, in early-stage studies, produced reduced cognitive decline and substantial beta-amyloid clearance. (Beta-amyloid is a protein found around the brain that, when clumped together, can form plagues that block neurons and lead to a progressive decline in cognitive function.) Unfortunately, early-stage success stories often miss the mark in later-stage studies, so the jury is still out on aducanumab.

Is cannabis the answer to Alzheimer’s disease?

However, researchers at the Salk Institute for Biological Studies believe the cure to Alzheimer’s disease might come from a readily available substance: marijuana.

In order to test their theory, researchers at the Salk Institute modified nerve cells to produce high levels of beta-amyloid. Researchers then noted that these higher levels of beta-amyloid production led to the expression of pro-inflammatory proteins and eventually nerve cell death. The ongoing death of these nerve cells is what leads to the progressive cognitive decline witnessed in Alzheimer’s patients. This itself was an intriguing finding, as it was long believed that an immune-like response, not the proteins themselves, led to nerve cell death.

Now here’s where things get interesting. As the researchers noted in their findings, nerve cells in the brain contain receptors that are activated by lipid molecules known as endocannabinoids, which are naturally produced by nerve cells. These endocannabinoids are believed to help nerve cells with their ability to send signals relating to appetite, pain sensation, and memory. Marijuana contains the chemical tetrahydrocannabinol (more commonly known as THC), which is similar to endocannabinoids and can activate those same nerve cell receptors. In other words, the researchers at Salk Institute hypothesized that cannabis could block the receptors that lead to the release of pro-inflammatory proteins and prevent nerve cell death.

For their test, the researchers applied THC to nerve cells producing high levels of beta-amyloid. The findings showed that beta-amyloid production was reduced, eliminating the pro-inflammatory protein response and sparing the nerve cells from death.

Understandably, this study would need to be tested in a well-controlled clinical setting to have validity, but it nonetheless offers significant hope that cannabis could hold the key to curing Alzheimer’s disease.

Before you get too excited…

While the findings from Salk Institute’s researchers are eye-opening and exciting from a medical standpoint — and they mark another victory for cannabis enthusiasts who’d like to see medical marijuana legalized throughout the country — the reality is that cannabis’ path to approval as a treatment for Alzheimer’s disease could be long and difficult.

If you recall, the U.S. Drug Enforcement Administration recently issued a ruling that will keep cannabis designated as a schedule 1 (i.e., illicit) substance. Although the DEA appears to be relaxing its stance on marijuana for the purposes of medical research, there are no guarantees that access to cannabis for medical research will improve anytime soon. This also complicates matters for residents living in the 25 states that haven’t legalized medical marijuana.

Furthermore, the Food and Drug Administration’s recommendation on cannabis seemed to coincide with that of the DEA. The stance of both the DEA and FDA is that much is still unknown about the chemical composition of marijuana and that marijuana has no recognized medical benefits. There are also unknowns surrounding its safety that could make it difficult for any marijuana or cannabinoid-based drug to make it past the FDA.

Beyond these restrictions on marijuana’s medical potential, the marijuana business in general faces some inherent disadvantages. Because marijuana remains an illicit substance at the federal level, marijuana businesses struggle to obtain basic financial services ranging from a checking account to lines of credit. Just 3% of the nation’s 6,700 banks are currently working with companies in the cannabis industry.

Marijuana businesses also face disadvantages come tax time. U.S. tax code 280E prohibits businesses that deal with federally illegal substances from taking normal business deductions, leaving them to pay tax on their gross profits instead of net profits.

Ultimately, marijuana has shown flashes of medicinal potential across a number of disease types, including Alzheimer’s disease. However, without controlled and FDA-approved clinical studies, the evidence needed to give marijuana recognized medical benefits just isn’t there. Unfortunately, both Alzheimer’s patients and investors looking to take advantage of marijuana’s potentially expansive growth prospects will have to watch and wait from the sidelines.

Source: The Motley Fool