In a bipartisan letter to dated Jan. 28, nine senators asked President Barack Obama to request additional funding for Alzheimer’s disease research in his budget for fiscal year 2017.

“At a time when the United States is spending more than $200 billion a year to care for Alzheimer’s patients, we are spending just 4% of that amount on research,” the senators wrote. “Although the administration and Congress have made some progress in increasing funding, Alzheimer’s research funding remains disproportionately low compared to its human and economic toll.”

The letter was signed by Sens. Kelly A. Ayotte (R-NH), Susan M. Collins (R-ME), Amy Klobuchar (D-MN), Edward J. Markey (D-MA), Barbara Mikulski (D-MD), Jerry Moran (R-KS), Debbie Stabernow (D-MI), Mark R. Warner (D-VA) and Sheldon Whitehouse (D-RI). Collins, who is chairwoman of the Senate’s Select Committee on Aging, led the effort with Klobuchar, Collins said in a Jan. 29 post on her website.

The National Institutes of Health invested $586 million in Alzheimer’s research in 2015. An appropriations bill approved in late 2015 would add $350 million in annual investment for research related to the disease, for a total of $936 million annually for Alzheimer’s disease research at the NIH, an increase of about 60% for fiscal year 2016. The senators are asking the president to propose an increase that would move the budgeted amount closer to the $2 billion that researchers say is needed.

“If nothing is done to change the trajectory of Alzheimer’s, the number of Americans afflicted with this disease is expected to more than triple by 2050,” Collins said. “By then, what is already our nation’s costliest disease is projected to cost our country more than $1 trillion each year.”