The chairman of the House Oversight Committee is expanding the committee’s review of Gilead Sciences’s patent claims relating to Truvada for PrEP, the company’s drug that prevents HIV infection.

In a letter released Thursday, Rep. Elijah E. Cummings (D-Md.) demanded emails and other information from Gilead about negotiations that led to Gilead’s pledge to donate free doses of the drug for President Trump’s effort to eradicate HIV by 2030.

Cummings also asked Gilead for details of contact with the Centers for Disease Control and Prevention and other agencies over its claim that U.S. government patents are invalid for Truvada for PrEP, as the preventive use is known.

The committee appeared to be asking whether there was any quid pro quo in the deal to provide the free HIV medication. The committee wants to know “whether Gilead’s donation of Truvada was connected in any way to patents’’ and “whether these patents played any role in negotiations between the company and the Department of Human Services,’’ said the letter.

Gilead has previously denied any connection between the patents and its deal to provide free HIV prevention pills. The San Francisco-based company has said it will donate 2.4 million bottles per year of Truvada for PrEP to the effort. The CDC will decide where the drugs should be distributed.

Gilead said Thursday that it received the committee’s letter and is reviewing it.

The Washington Post reported in March that the government was not enforcing its 2015 patents on Truvada for PrEP. That led to a contentious hearing by the Oversight Committee in May where Gilead chief executive Daniel O’Day insisted CDC patents on the use of Truvada for PrEP are invalid.

The Justice Department’s intellectual property division also opened a review of the matter, which would be a first step if the government decided to get more aggressive, The Post reported .

Cummings’s request follows a letter he and Sen. Debbie Stabenow (D-Mich.) sent last week to the Government Accountability Office asking GAO to dig into the patent enforcement practices of the Department of Health and Human Services.

If Gilead is infringing on the government’s Truvada patent, “this would mean that a private entity has generated billions of dollars in revenue over several years while infringing on government-owned intellectual property, and that the government either failed to detect the infringement or was aware but failed to prevent it,’’ Cummings and Stabenow wrote.

Cummings was joined on the letter released Thursday by three liberal Democrats on his committee, Reps. Alexandria Ocasio-Cortez of New York, Ayanna Pressley of Massachusetts and Ro Khanna of California.

The representatives also asked Gilead to explain how it sets Truvada’s price. They noted that the wholesale list price of Truvada for PrEP rose from $1,289 for a monthly supply in 2012 to $2,109 this year, a 63 percent increase.