Alzheimer’s disease is the sixth leading cause of death in the U.S., but researchers have recently completed the first phase III clinical trial for a drug that targets a specific protein linked to the progression of the disease.

The protein in question is called tau, and is responsible for forming twisted fibers in the brain called “tangles,” which are believed to contribute to nerve cell death.

In a study recently presented at the Alzheimer’s Association International Conference 2016, researchers explained that a drug called LMTX has shown promise for halting the formation of these tau tangles.

According to researchers, LMTX is classified as a tau aggregation inhibitor (TAI), which means it has the ability to target tau in the brain and then prevent it from forming the damaging tangles.

Scientists have been attempting to treat tau tangles and amyloid plaques, the two main components of Alzheimer’s disease, for years. Now, LMTX offers a possible solution to one of the issues.

Dr. Serge Gauthier and colleagues at McGill University in Canada have completed the first ever phase III trial of this drug, which proved beneficial for a small subgroup of patients.

For this phase III trial, Gauthier and his colleagues recruited 891 patients from over 16 different countries, all of whom were suffering from mild to moderate Alzheimer’s disease.

Patients were randomly assigned one of three different dosages of LMTX for 15 months, with approximately 85% already using another approved form of treatment for the disease.

Surprisingly, researchers found that patients who were not using any other form of treatment experienced improved cognitive function, as well as a decrease in brain atrophy.

While LMTX is making headlines, there is another substance that researchers claim could be beneficial to the treatment of Alzheimer’s.

“It is reasonable to conclude that there is a therapeutic potential of cannabinoids for the treatment of Alzheimer’s disease,” wrote David Schubert, senior researcher and a professor at Salk Institute for Biological Studies.

In a recent study conducted by Schubert, THC, the psychoactive ingredient in cannabis, was found to help stimulate the removal of toxic plaque in the brain, which is one of the leading issues regarding Alzheimer’s disease.

Similarly, two Dutch scientists in 2014 found that marijuana was useful in treating the behavioral symptoms of dementia.

While studies like these and the clinical trials of LMTX have only shown advances in a very small population, the results still have researchers hopeful for the development of a preventative treatment, or even a cure in the future.