WASHINGTON — The Republican health care plan moving rapidly toward a crucial House vote this week is likely to be changed to give older Americans more assistance to buy insurance, Speaker Paul D. Ryan said Sunday.

‘‘We think that we should be offering even more assistance than what the bill currently does,’’ the Wisconsin Republican said in a ‘‘Fox News Sunday’’ interview, in which he confirmed that House leaders expected a Thursday floor vote on it.

Meanwhile, a key conservative senator said White House officials were continuing to negotiate through the weekend on even more dramatic revisions to the bill in hopes of winning over hard-liners who have threatened to oppose the legislation.


Senator Ted Cruz, Republican of Texas, said he and two other conservative leaders — Senator Mike Lee, Republican of Utah; and Representative Mark Meadows, Republican of North Carolina, chairman of the House Freedom Caucus — met at President Trump’s Mar-a-Lago resort in Florida in an attempt ‘‘to fix this bill.’’

‘‘I cannot vote for any bill that keeps premiums rising,’’ Cruz said, echoing the concerns of other hard-line lawmakers who want the legislation to undo more of the Affordable Care Act’s insurance mandates.

‘‘President Trump said this is one big, fat negotiation,’’ Cruz said. “Here is the central prize: If we lower premiums, and hopefully lower them a lot, that is a victory for the American people.’’

The number of votes needed to pass the legislation in the House is 218, and in the Senate, 50.

Republicans have a slim majority in both chambers, but assuming no Democrats support the bill, they can afford to lose only 21 Republican votes in the House and just two in the Senate, according to a Washington Post tally.

As of Sunday morning, the number of Republicans in Congress who have expressed serious concerns about the bill as it stands — or outright said they would vote against it — is enough to kill the bill in both chambers: 20 senators and 45 House lawmakers.


Still, Ryan expressed confidence that the bill would pass the House this week — and then move to the Senate. He cited Trump’s hands-on involvement as a key factor is moving the legislation forward.

‘‘The president is bringing people to his table, and I’m very impressed with how the president is helping us close this bill, and making the improvements that we’ve been making. . . . We are right where we want to be,’’ Ryan said.

Ryan’s declaration that more would be done to help older Americans came after a third House moderate said Saturday that he could not support the bill ‘‘in its current form.’’

Representative Brian Fitzpatrick, Republican of Pennsylvania, who represents a suburban Philadelphia district that has been heavily targeted by Democrats, said in a Facebook post that he was most concerned that the legislation would roll back efforts to prevent and treat opioid abuse.

But he said that was one concern of many, and lawmakers from across the GOP’s ideological spectrum have expressed fears that the American Health Care Act will not drive down prices. Republican Representatives Ileana Ros-Lehtinen, of Florida, and Leonard Lance, of New Jersey, have cited that concern in announcing their opposition to the bill, and several other moderates remain undecided.

Those fears were stoked last week by a Congressional Budget Office analysis that forecasted a short-term increase in premiums under the GOP law, and while premiums are expected to drop by roughly 10 percent over a 10-year horizon, some older and low-income people would face massive premium increases.


Those over 50 but not yet 65 — and thus eligible for Medicare, the federal health program for seniors — represent a major issue in forging an alternative to the ACA.

That age group tends to have more medical issues than younger adults and, thus, higher insurance costs, and the ACA forbids insurers from charging their oldest customers more than three times their rates for young adults — essentially having young adults cross-subsidize the cost of coverage for older ones.

But House Republicans want to eliminate that feature of the law, and the GOP bill would allow a five-to-one ratio as part of an attempt to attract more of the younger, healthier customers whom insurers want.

In an extreme case laid out in the CBO report, a 64-year-old earning $26,500 a year would see yearly premiums rise from $1,700 under the ACA to $14,600 under the GOP plan.

Ryan questioned that analysis, suggesting that administrative actions taken by the Trump administration would further lower premiums and questioning whether the ACA would remain viable in a decade. But he acknowledged that the GOP bill would probably have to change.

‘‘We believe we should have even more assistance, and that’s one of the things we’re looking at for that person in the 50s and 60s because they experience higher health care costs,’’ he said.


The GOP bill as currently written offers a fixed tax credit for low- and middle-income Americans that rises by age. But it does not rise and fall, like the ACA’s subsidies, so a person pays only a fixed percentage of their income on their health insurance premiums.

That, according to the CBO estimate, leads to substantial cost savings that — together with cuts to Medicaid — allow the GOP plan to eliminate nearly all of the taxes imposed under the ACA.

Trump won the support of several conservative House members on Friday when he agreed to make changes to the Medicaid portion of the bill, including giving states the option of instituting a work requirement on childless, able-bodied adults who receive the benefit.

But Senator Rand Paul, Republican of Kentucky, who has worked closely with the hard-right bloc in the House, asserted on ‘‘This Week’’ that the bill was still short of a majority.

‘‘They still believe that the conservatives in their caucus don’t want Obamacare Lite,’’ he said. ‘‘I believe that the real negotiation begins when we stop them. You have to stop them.’’