Blood tests outperform doctors at diagnosing Alzheimer’s

Hello Health Rounds readers! With two Alzheimer’s treatments now available that appear to work best when used early in the disease, today we bring news of blood tests that proved far better than doctors at diagnosing the mind-wasting condition.

We also report on a study of liver transplants for patients with colon cancer that has spread to the liver and early data on a method for preventing relapses after CAR-T cell cancer treatment.

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A commercially available blood test did a better job of detecting Alzheimer’s disease than primary care doctors or specialists using traditional tools, according to findings from a large study.

Patients being evaluated for cognitive problems were tested with C2N Diagnostics’ PrecivityAD2 blood test, which looks for fragments of amyloid beta and tau proteins known to be associated with plaques in the brain that are characteristic of Alzheimer’s disease.

Among 698 patients seen at memory clinics, the C2N test was 91% accurate at identifying Alzheimer’s disease, while specialists using clinical exams, cognitive testing, and computed tomographic scans were 73% accurate, researchers reported at the Alzheimer’s Association International Conference in Philadelphia on Sunday.

Among 515 patients seen in primary care, the C2N test was also 91% accurate, while primary care physicians were 63% accurate.

“These results were especially impressive considering that older populations in primary care often have medical conditions that can influence or vary the concentrations of p-tau217,” study leader Dr. Sebastian Palmqvist of Lund University in Sweden said in a statement, referring to one of the Alzheimer’s-related proteins.

The average age in the study, which was also published in JAMA, was roughly 74 years.

Presently, no single test can distinguish Alzheimer’s disease from other forms of dementia. Workups can be expensive, invasive and not always accessible, the researchers said.

“This study makes the case convincingly that highly sensitive blood measures of Alzheimer disease can be integrated into the clinical decision-making process, including in the primary care setting,” a JAMA editorial notes.

“Accurate and early diagnosis of Alzheimer’s disease is increasingly important because of the new era of monoclonal antibodies targeting amyloid reduction in the brain,” it said.

There are now two U.S. approved treatments for early Alzheimer’s.

A separate study presented at the meeting on Monday compared the accuracy of six commercial blood tests for detecting Alzheimer’s disease.

“The top two performers across all measures” were C2N Diagnostics’ PrecivityAD2 and Lumipulse from Belgium’s Fujirebio, the authors of that study said in a press release.

A small study adds to evidence that for some patients with colorectal cancer tumors in the liver, a liver transplant may yield better outcomes than usual medical therapies.

Because of the shortage of organs for transplant, patients with inoperable colorectal cancer that has spread to the liver are typically limited to receiving palliative chemotherapy. More recently, surgeons have begun to offer liver transplants to highly selected patients.

At the University of Rochester Medical Center in New York, doctors tracked 33 patients whose colorectal cancer was under control but whose liver tumors could not be surgically removed.

Based on clinical risk factors and tumor biology, all 33 were eligible for a liver transplant under current guidelines, but only 20 chose that route. The others opted for traditional medical therapies or less extensive surgeries.

During the next three years, cancer progression was seen significantly less often in the transplant recipients, researchers reported in JAMA Surgery.

At one year, 90% of transplant patients showed no sign of cancer progression. That dropped to 73% after two years and 36% at three years. Among patients who opted for other treatments, survival without disease progression was 42% after one year and just 10% after two and three years. 

At three years, 90% of transplant patients were still alive, compared to 73% of patients who received other therapies, although the difference was not statistically significant.

“Unfortunately, liver transplantation is not for every single patient who has advanced metastatic disease in the liver,” Dr. Roberto Hernandez-Alejandro, chief of abdominal transplant and liver surgery at URMC, said in a statement.

“The way we can have good results … is by establishing strict criteria based on tumor biology, the behavior of these tumors, how well they respond to chemotherapy.”

Lab experiments may be pointing toward a solution to high rates of relapse after cancer treatment with CAR-T cell therapies, researchers said on Tuesday in Nature Biotechnology.

These therapies have revolutionized treatment of some blood cancers, but many patients – even those who achieve full remission – eventually relapse.

“In myeloma, for example, virtually 100% of patients have an excellent response to CAR-T cell therapies initially, but almost all relapse, half of them within one to two years of treatment,” study leader Mohammad Rashidian of Dana-Farber Cancer Institute in Boston said in a statement.

CAR-T cells, created by taking the patient’s own immune cells and genetically modifying them before reinfusion, destroy all but a tiny percentage of cancer cells, Rashidian said.

Then “they act as if their job is done and go away,” he said. Relapses coincide with the disappearance of CAR-T cells in the bloodstream.

The new approach works by delivering a molecule that spurs CAR-T cells to be more active and persist longer in the body and to remember the cancer cells so they can react to a recurrence, the researchers said.

The “CAR-Enhancer,” or CAR-E, treatment also causes CAR-T cells to diversify into a wider repertoire of immune cells, allowing for a more effective response with a lower dose of the cells, they said.

In laboratory cultures of human myeloma cells and in animal models of the disease, CAR-E treatment brought about the complete clearance of tumor cells, the researchers said.

If further research leads to trials of the approach in humans, the researchers said they expect CAR-E treatment would begin about a month after patients are infused with CAR-T cells, with a weekly dose of CAR-E therapy for three or four weeks.

This newsletter was edited by Bill Berkrot; additional reporting by Shawana Alleyne-Morris.

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