Two drugmakers have made a practice of buying and then dramatically hiking the prices of low-cost drugs given to patients with life-threatening conditions including heart disease, AIDS and cancer, according to excerpts from thousands of documents released by federal lawmakers.

A congressional review of more than 300,000 pages from Turing Pharmaceuticals and Valeant Pharmaceuticals reveals how executives planned to maximize profits while fending off negative publicity over the price hikes.

Rep. Elijah Cummings, D-Maryland, released the information Tuesday ahead of a hearing Thursday to examine exorbitant price spikes. Cummings has used his position atop the House Committee on Oversight and Government Reform to investigate several companies that have bought previously low-cost drugs and jacked up their prices many times over.

The Democrat said in a statement that the documents show “that many drug companies are lining their pockets at the expense of some of the most vulnerable families in our nation.”

When reached Tuesday, Valeant and Turing said they’re committed to ensuring that cost isn’t a deterrent for patients.

At the center of the investigation is Turing’s former CEO Martin Shkreli, who became the poster child of pharmaceutical-industry greed last fall for hiking the price of a life-saving drug by more than 5,000 percent. That drug, Daraprim, is the only approved medication for a parasitic infection which mainly strikes patients with weakened immune systems, including those with cancer and AIDS. The patent on the drug expired decades ago.

Company presentations released Tuesday show that as early as last May, Turing planned to turn Daraprim into a $200-million-a-year drug by dramatically increasing its price. Turing purchased the six-decade-old drug from Impax Laboratories in August for $55 million and promptly raised its price.

Shkreli said in an email to one contact: “We raised the price from $1,700 per bottle to $75,000. Should be a very handsome investment for all of us.”

But anticipating a possible backlash, the company warned in an internal memo: “HIV patient advocacy may react to price increase … HIV community is highly organized, sensitive and action-oriented.”

The price increase left some patients with co-pays as high as $16,000, according to the committee’s review of more than 250,000 pages of documents from New York-based Turing.

Turing said Tuesday in an emailed statement that it is “committed to ensuring that no patient will ever be denied access to Daraprim because of cost.”