WASHINGTON -- Angered by skyrocketing drug prices, a pair of senators on Wednesday urged Congress to block companies from cornering the market on old, off-patent drugs.

Sens. Claire McCaskill, D-Mo., and Susan Collins, R-Maine, released findings from a yearlong investigation into companies such as Turing Pharmaceuticals, which generated national outrage last year after hiking the price of a life-saving anti-infection drug by more than 5,000 percent.

"We've got to find ways to increase competition for medicines and ensure that patients and their families aren't being gouged," McCaskill said.

Committee investigators concluded Turing and several other companies "engaged in price gouging ... to make massive profits from decades-old life-saving therapies."

The lawmakers, top members of the Special Committee on Aging, presented similar findings at three hearings over the past year.

The 131-page report comes as lawmakers and pharmaceutical executives try to gauge President-elect Donald Trump's interest in government intervention to curb rising drug prices, a leading health-care concern among patients.

While campaigning, Trump said he would support efforts to allow Medicare -- the massive government health plan for seniors -- to negotiate drug prices directly with manufacturers, a step long opposed by the pharmaceutical lobby.

That policy does not appear among the health-care proposals currently outlined on Trump's website. The list includes a policy allowing importation of cheaper drugs from Canada and other countries, another proposal opposed by drugmakers.

Representatives for Trump did not respond to requests for comment Wednesday.

A day earlier, 19 senators sent a letter to Trump, urging him to follow through on pledges to help lower drug prices.

"During your campaign, you promised to implement bold reforms to bring down the cost of prescription drugs," states the letter, signed by 17 Democrats and independent Sens. Bernie Sanders of Vermont and Angus King of Maine. "We are ready to advance bipartisan reforms that will help achieve the goal we all share: reducing the burden exorbitant drug prices are placing on hard-working Americans."

The new report draws similarities between the tactics of companies such as Turing and Valeant Pharmaceuticals and investment firms that profit by buying undervalued stocks and pushing up prices.

Investigators note Turing's former CEO, Martin Shkreli, and several other executives probed by the committee previously worked at hedge funds.

"This may help explain why these companies may have been run more like hedge funds than pharmaceutical companies," the report states.

Shkreli stepped down as the head of Turing after prosecutors charged him with securities fraud late last year. Valeant is the target of more than 10 government probes, plus multiple shareholder lawsuits.

Turing said in a statement Wednesday it has taken several steps to increase access to its drug, daraprim, including offering discounts to hospitals. The drug still carries a list price of $750 per pill.

"It is disappointing that the report takes out of context and selectively highlights certain comments, including from past employees that are not reflective of Turing's current commitments and efforts," the company said.

A Valeant spokesperson did not immediately respond to a request for comment.

McCaskill and Collins call for several legislative steps intended to increase price competition, including giving priority review to drugmakers that develop cheaper versions of drugs that are available only from a single company.