Alzheimer's: Just what is it? There may be more than one cause

Jan. 08--Alzheimer's disease may not even exist as a singular entity, any more than cancer. If that's so, it would explain the massive and costly failures in treatment. But it also gives hope that, like cancer, an array of treatments may begin to defeat it.

This and other proposals to rethink Alzheimer's from the beginning were explored Tuesday morning at a panel discussion at Biotech Showcase, part of a massive gathering of life science professionals this week in San Francisco.

Panelists included two CEOs of companies developing targeted Alzheimer's therapies; a venture capital investor in the area; and a biotech analyst.

They said the hardest thing about treating Alzheimer's may be how we think about it. If many different causes converge to produce the symptoms of Alzheimer's, it's not surprising that even the best-developed therapies have failed.

From a business perspective, it would be less expensive to test drugs aimed at segments of patients, said Kenneth Moch, president and CEO of Cognition Therapeutics. The company is developing a drug against a soluble form of beta amyloid, a toxic brain protein implicated in Alzheimer's.

Alzheimer's drugs have required thousands of patients, because large numbers are required to determine effectiveness against a widely prevalent disease. But drugs for rare diseases can be tested with fewer patients, Moch said.

"That's part of the reason you see large-cap pharma getting out of this business," Moch said. "Let's be realistic: It's a lot easier to make money in a rare and ultra-rare disease."

Casey Lynch, CEO of Cortexyme, said her company kept costs down with its drug, which treats a brain infection that may cause buildup of toxic proteins. The drug recently completed an early or Phase 1 trial, which showed safety and hints of potential efficacy.

"We got through Phase 1 with about $15 million," Lynch said. "It's a combination of a good team and luck, frankly."

Another thing working in the company's favor is that it has a single target, and put an "extreme focus" on gathering pertinent data, she said.

Lynch said it's quite possible that other pathogens may also trigger Alzheimer's. It's now known that the brain isn't sterile, but care will be needed to be sure that the microbe in question actually cause Alzheimer's.

Cause and effect is a big problem with the animal models of Alzheimer's now used to test disease theories, Lynch said. These models, usually rodents engineered to produce toxic brain proteins, simply aren't realistic models of human disease. So it's no wonder that drugs tested on these models don't work in real Alzheimer's patients.

"Our mouse model is just a regular old mouse with a regular old infection," Lynch said.

But the best disease model of a human disease is real humans, said Barbara Tate, a neuroscientist and venture partner at Dementia Discovery Fund and SV Life Sciences. The fund looks for dementia treatments as a social good, but also tries to make money in the process.

"We need to ground the preclinical models in human disease," Tate said. That should include closer studies of the brains of deceased Alzheimer's patients, she said.

Taking that logic a step further, the best marker of decline in cognition is a decline in cognition itself, Tate said. And the most important tools for that assessment may already be in your hand.

"We are all walking around with a computer that can help us to understand if we're an appropriate patient, and actually get feedback during a clinical trial," Tate said of the now-ubiquitous smartphone.

There is precedent for optimism in the development of cancer immunotherapy, said John Vandermosten, a senior biotechnology research analyst for Zacks Investment Research. Drugs such as checkpoint inhibitors, which activate the immune system against cancer, took a long time to develop.

"Since then, we've seen a lot of improvement in that space," Vandermosten said. "Once we crack the code, so to speak, in Alzheimer's, it's going to be a fast flow."

bradley.fikes@sduniontribune.com

(619) 293-1020

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