Judith Chase Gilbert is briefed by Nuclear Medicine Technologist J.R. Aguilar before taking part in a study on Alzheimer's disease at Georgetown University Hospital in May 2015. (Evan Vucci/AP)

The spending deal Congress reached Tuesday night includes an unprecedented increase in funding for Alzheimer’s research: $350 million in fiscal 2016. If approved by the White House, it will increase government spending on the disease by over 50 percent.

Advocates have long pushed for significant increases in Alzheimer’s spending, calling it a coming crisis and saying it should be funded at the same level as cancer, HIV/AIDS and heart disease research.

A panel of scientists convened by the Alzheimer’s Association estimated that the National Institutes of Health would need $2 billion a year to maximize the chances of curing or preventing the disease by 2025. This year’s increase puts the NIH well on its way toward that goal.

“It’s perhaps some of the most encouraging news we’ve had on Alzheimer’s disease in several years,” said Ronald Petersen, director of the Mayo Clinic Study of Aging and the Mayo Alzheimer’s Research Center. “This is truly very, very exciting in the field.”

If each year the funding is increased by $350 million, he noted, the $2 billion goal would be reached by 2020.

That is significant, advocates say, because the United States faces a ticking time bomb in terms of the financial and personal costs of Alzheimer’s.

By 2025, the number of people age 65 and older with Alzheimer’s is estimated to reach 7.1 million — a 40 percent increase from 5.1 million today, according to the Alzheimer’s Association.

Spending on Alzheimer’s and other dementias is $226 billion a year, over two-thirds of which comes from Medicare and Medicaid.

The proposed increase is many times larger than last year’s, when a $25 million increase was budgeted for Alzheimer’s research. That brought NIH funding to $586 million in fiscal 2015 — a negligible amount compared with HIV/AIDS and heart disease, which receive $3 billion and $1.6 billion, respectively.

Alzheimer’s was “not in the ballpark,” Petersen said. “And yet people predict that Alzheimer’s is the disease of our time.”

Without significant breakthroughs to cure or prevent the disease, the number affected by 2050 could rise to 13.8 million, with costs soaring to as much as $1.1 trillion a year in public and private spending.

Currently, 18 percent of Medicare dollars are spent on people living with Alzheimer’s and other dementias, according to an Alzheimer’s Association report. If things don’t change, Medicare costs will more than quadruple in 2050 — from $113 billion in 2015 to $589 billion, or one in three Medicare dollars.

If the $2 billion goal is met, however, costs would be expected to fall by hundreds of billions of dollars a year. For example, if in 2025 a treatment became available to delay the onset of Alzheimer’s disease by five years, Medicare would save $345 billion over the following decade.

If funding boosts for the disease continue at the level of this year’s increase, it would be a game-changer, said Rob Egge, chief policy officer at the Alzheimer’s Association.

“There have been outstanding scientific proposals, and they have been sitting on the sidelines, with scientists waiting to go, for lack of funding,” he said. “These are going to be able to be dusted off and acted on.”

Lawmakers have been hearing from constituents about the need to act on Alzheimer’s, Egge said, adding that the expected bulge in aging Americans has made the disease a stark priority. “By 2050, one half of baby boomers will be living with Alzheimer’s disease,” he said.

NIH declined to comment on the budget until it is final.

Alzheimer’s and other dementias are caused by the buildup of microscopic clumps of a protein fragment called beta-amyloid and twisted strands of a protein called tau, which clog the space between brain cells and impede the transmission of information from cell to cell.

Scientists predict that one day, Alzheimer’s will probably be treatable with a “cocktail” of medications tailored to an individual’s genes and other factors.

A key part of research will lie in identifying predictors of Alzheimer’s — through memory and thinking tests and MRI scans — before symptoms occur. Scientists hope that, similar to heart disease, Alzheimer’s can one day be identified and targeted in at-risk patients before the disease manifests itself.

The funding increase means scientists will also be able to pursue new avenues.

“We can start to advance our research deeply, not just in one or two areas, but also pursue at the same time many other areas that could also lead to those treatments that we’re looking for,” Egge said. “We think it’s just what is needed.”