Democratic presidential candidate Senator Bernie Sanders participates in a town hall forum hosted by CNN at Drake University on January 25, 2016 in Des Moines, Iowa. Pool photo by Justin Sullivan/UPI | License Photo

WASHINGTON, Jan. 26 (UPI) -- Bernie Sanders announced he's joining two of his fellow senators in working to block President Obama's choice to lead the Food and Drug Administration.

"At a time when millions of Americans cannot afford to purchase the prescription drugs they require, we need a leader at the FDA who is prepared to stand up to the drug companies," Sanders told Politico on Tuesday, opposing Dr. Robert Califf's nomination to head the agency.


"Dr. Califf's extensive ties to the pharmaceutical industry give me no reason to believe that he would make the FDA work for ordinary Americans, rather than just the CEOs of pharmaceutical companies," Sanders added.

Sen. Bernie Sanders, D-Vt., joins Sens. Lisa Murkowski, R-Alaska, and Ed Markey, D-Mass., who have vowed to block the appointment of Dr. Robert Califf for other reasons.

Califf's appointment was announced in September. Sanders voiced opposition the following month after speaking with Califf.

Califf has been a deputy commissioner at the FDA for nearly a year. A cardiologist and Duke University researcher, The New York Times reported in September that Califf has the deepest ties to the pharmaceutical industry of anyone selected to lead the agency in recent memory.

At issue is Califf's multi-million dollar clinical research lab at Duke, which received more than 60 percent of its funding from pharmaceutical companies. In 2014, Califf also earned more than $100,000 consulting for pharmaceutical giants like Merck and Novartis.

RELATED Clinton vows to target drug speculators

Sanders, who is leading in polls for the Democratic nomination for president in the two early voting states of Iowa and New Hampshire, has made pharmaceutical companies a frequent target on the campaign trail.

On Monday, Markey announced he would do his part to hold up Califf's appointment until the FDA changes its approval process for opioid painkillers. Last year, the FDA approved the use of OxyContin to treat children as young as 11 years old.

"While people in every community across the country are dying every day from opioid overdoses, the FDA continues to operate as if safety just means the right dose when it should include all the dangers of these painkillers," Markey said in a statement.

Murkowski announced her intent to block Califf earlier this month, saying in a statement that she intended to do so unless the FDA required mandatory labeling of genetically modified salmon.

After agency appointments are cleared from the committees that have jurisdiction over them, they move to the full Senate for confirmation. Unanimous consent is required to place a confirmation hearing on the Senate calendar; Senators can block confirmations by withholding consent to schedule the confirmation hearing, which results in a "hold" on the nomination.

Since Califf's appointment already cleared the Senate Committee on Health, Education, Labor and Pensions on Nov. 17, senators like Sanders, Markey and Murkowski can exercise their power to place a hold on the process.