Federal officials said they were focusing on the anticompetitive practices of brand-name drug makers under the impetus of a vow by President Trump to hold down prices set by drug companies, which he has said are “getting away with murder.”

Legislation to ensure access to drug samples for generic drug manufacturers has broad support in Congress, from Senator Patrick J. Leahy, Democrat of Vermont, on the left to Senator Mike Lee, Republican of Utah, on the right. A similar bill in the House also has diverse backers, including Representatives Peter Welch, Democrat of Vermont, and Mark Meadows, Republican of North Carolina, who is the chairman of the conservative House Freedom Caucus.

Under the bill, a generic drug developer could file a lawsuit, and a federal court could require a brand-name drug maker to provide samples of its product to a generic company “on commercially reasonable, market-based terms.” The court could also award damages if it found that a drug maker had refused to sell samples “without a legitimate business justification.”

Brand-name drug companies make several arguments against the legislation. First, they say, it is not needed. The F.D.A. approved 1,027 generic drugs last year, a record number, and nearly 90 percent of prescriptions are filled with generic medicines, suggesting that generic manufacturers have generally been able to obtain the samples they need, the brand-name companies say.

Second, they say, the bill would be a boon to trial lawyers, giving them an incentive to sue brand-name pharmaceutical companies for damages, which could be worth more than sales of the proposed generic drug.