The resulting blend of ginkgo biloba, ginseng and saffron extracts, called Sailuotong or SLT, is due to enter a late-stage study in Melbourne this month, and a larger clinical trial to validate its impact is slated to begin in China later this year.

The herbal mix offers an untrodden avenue into a research field riddled with failures. Success for SLT could bring the first approved medicine to treat the vascular causes of dementia, a form of age-related deterioration that resembles Alzheimer’s disease. But its backers’ hopes extend beyond dementia: they seek to validate a new approach to pharmaceutical innovation combining the ancient wisdom of traditional medicines with the scientific rigor of modern drug development.

“If we’re successful in treating vascular dementia, it will be a good example of how other traditional Chinese medicines could potentially be developed,” said Zhang Huajian, the Beijing-based director of clinical research at China Shineway Pharmaceutical Group Ltd.

Dementia, afflicting about 50 million people worldwide, is a compelling target. Despite hundreds of clinical trials investigating potential treatments in recent decades, no new drug has been approved since 2003. The five medications sold for Alzheimer’s, the most common cause of dementia, provide only modest relief of symptoms. None can slow the disease’s progression. There are no specific drugs for vascular dementia, which SLT targets.

Chinese herbal ingredients are already used in some important medicines, including the main treatment for malaria, thanks to a tradition preserved in texts such as Huangdi Neijing, the most important book of ancient Chinese medicine. The group that invented SLT is also working along a similar route to develop treatments for diabetes and related ailments.

While modern pharmaceuticals tend to work on single targets, herbal extracts used in traditional Chinese medicine can interact with the body along multiple pathways, according to Zhang.

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Unusual scrutiny

For SLT, researchers isolated the chemical components from each ingredient, identified and characterized their biological activity, and then studied multiple combinations to determine the optimal formulation.

Each capsule contains 10 active components, according to the drug’s inventor, Liu Jianxun, director of the research center at the China Academy of Chinese Medical Sciences’ Xiyuan Hospital in Beijing. Liu and colleagues documented how and where each component is taken up in the body, as well as the effects and mechanisms of action.

It’s a level of analysis that has tended to elude traditional Chinese medicines, but which is needed for quality control and standardization, said Liu, who began working on the project in 1999, a decade before SLT was licensed to Shineway.

“Traditional Chinese medicine has advantages in treating geriatric and chronic diseases,” Liu said over the phone from Beijing, where he is also director of the standardized Chinese medicine pharmacology laboratory with China’s Ministry of Science and Technology. “We want to develop better medicines for dementia, regardless of the cause.”

Each of SLT’s ingredients has been used individually in traditional medicine, said Dennis Chang, a clinical pharmacologist at the University of Western Sydney’s NICM Health Research Institute. Chang is chief investigator of the final phase study in Australia.

Ginkgo biloba is taken to improve neurocognition and Panax ginseng is used as a “wonder herb” whose benefits include boosting memory and response. Saffron, a spice derived from the flower of Crocus sativus and used to flavor chicken soup in China, has a reputation for aiding blood circulation and offering antidepressant effects, he said.

In SLT, the combination is designed to work to improve blood circulation and perfusion in the brain, reduce inflammation and enhance communication between brain cells, according to Chang.

In vascular dementia, brain cells are killed by small strokes and other injuries that impede oxygen supply, causing changes in memory, thinking and behavior. While dead neurons can’t be recovered, the aim is to preserve and possibly increase brain function by improving the networks linking healthy cells, Chang said. The same benefits may apply across other forms of dementia, since vascular changes are found in the brains of a large proportion of deceased sufferers on autopsy.

“We never say we will try to find a cure, but that there will be a significant slowdown of disease progression -- that’s the hope,” Chang said.

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Familiar ingredients

A 16-week pilot study of SLT in 17 vascular dementia patients used single-photon emission computerized tomography scans to look for changes in blood circulation in the brain and found improvements in areas that control cognition, language comprehension, and working memory, he said. That supported a mid-stage study in China, where SLT was found to improve cognition and daily functioning in patients with mild-to-moderate vascular dementia.

The randomized, controlled study in Australia will enroll 230 patients, each of whom will take two capsules containing either SLT or a placebo twice a day for a year.

The China one aims to recruit about 500 patients, according to Shineway’s Zhang. Studies in both countries are expected to be completed in 2020 with a possible market launch in 2021, Shineway said in May. SLT would probably cost about 5,000 yuan ($730) for one year of treatment, Zhang said.

“This is a hopeful study,” said Amy Brodtmann, a cognitive neurologist who heads the vascular neurodegeneration research laboratory at the Florey Institute of Neuroscience and Mental Health in Melbourne.

Brodtmann plans to enroll patients in the SLT trial. One advantage, she said, is that the active ingredients are “used and taken in everyday life all the time. The chances of an adverse outcome are incredibly low.”