The changes were part of an intensive effort Democrats have made in recent days to satisfy the conflicting demands of liberals and conservatives on the panel. "We have agreed we need to pull together," said Rep. Henry Waxman, D-Calif., the committee chairman. He said he hoped for a vote by early evening.
Several officials said the cost of insurance to be sold widely under the bill could not rise by more than 4 percent a year unless the government approved.
The officials who disclosed the terms of the last-minute agreement did so on condition of anonymity, saying they were not authorized to discuss private deliberations.
The White House declined to state a position on the changes.
Passage in the committee would clear the way for a vote in the full House as early as September on Obama's drive to remake the face of health care. The pace is far slower than the White House or Democratic leaders had hoped, but still faster than in the Senate.
There, one committee has approved legislation, and bipartisan negotiations in a second panel are scheduled to continue next week as three Republicans and three Democrats reach for a deal.
At their core, all the measures under consideration are designed to achieve Obama's goal of extending health care to millions who lack it while slowing the growth of medical costs nationwide. Insurance companies would be required to sell coverage to all seeking it, without exclusions for pre-existing medical conditions. The federal government would provide subsidies for lower-income families to help them afford policies that would otherwise be out of their reach.
The main expansion of coverage would not come until 2013 — after the next presidential election.
The House bill also calls for the government to sell insurance in competition with private industry, a hotly contested provision.
The political stakes are enormous for Obama and the Democrats as they strive to pass legislation that has proven elusive for years. Republicans are overwhelmingly opposed to the approach they chose, and outside groups on both sides of the issue arranged a heavy dose of television advertising over August.
Waxman's announcement of a series of last-minute changes capped a tumultuous period that began more than two weeks ago when conservative and moderate Democrats on the panel sought changes.
Needing their votes, Waxman began negotiations that grew to include Speaker Nancy Pelosi and White House Chief of Staff Rahm Emanuel. An agreement at midweek excluded more businesses from a requirement to offer insurance to their workers and reduced subsidies for lower-income uninsured. It also swiftly triggered a counter-revolt among liberals, who demanded the subsidies be restored in full.
The final deal accommodated them without sacrificing the concessions made earlier to the conservatives, and included numerous other provisions.
U.S. House Speaker Nancy Pelosi said "the glory days are coming to an end" for the health insurance industry and predicted it will fail to stop healthcare overhaul legislation moving through Congress.
Insurance plans sold in the exchange would need government approval before increasing premiums by more than a set amount, which numerous aides said was 4 percent annually.
The provision giving the federal government the right to negotiate for better drug prices under Medicare has long been a goal of Democrats who say it could lower costs for seniors. Critics argue that is unlikely unless Congress also limits the drugs than can be sold, thereby giving the government the ability to play one company off against another.
That has long been viewed as politically unfeasible under Medicare, because it would limit the choice that seniors now enjoy.
But including restrictions in the government health insurance option would place it in line with Medicaid, the government program for the poor, as well as the Department of Veterans Affairs and many private plans that limit drug choice.
The last-minute agreement mollified liberals who were outraged by a deal Waxman struck earlier in the week with conservatives known as the Blue Dog Democrats. "We felt it was paid for on the backs of some of the people who can't afford health insurance now," said Rep. Diana DeGette, D-Col0.
Lawmakers from both camps said Friday they were now in accord. "We need to get this done," said Rep. Baron Hill, D-Ind., one of the Blue Dogs.
In the Senate, bipartisan negotiators took the weekend off, after a near derailment in their effort on Thursday.
Sen. Max Baucus, D-Mont., said on Thursday talks would resume next week, but it was unclear how much longer the White House and Majority Leader Harry Reid, D-Nev., would wait before seeking an alternative.