The bill also implements a first-to-file standard consistent with international practice.

"Intellectual property industries not only drive a significant part of the American economy, but also provide millions of Americans with well-paying jobs," bill co-sponsor Lamar Smith (R-Texas) said in a statement. "The Patent Reform Act protects intellectual property by addressing critical weaknesses in the current law and eliminating the legal gamesmanship that rewards lawsuit abuses over creativity."

The bill now goes before the full U.S. House for an as yet unscheduled floor vote. Similar legislation is pending before the Senate Judiciary Committee, which has a vote scheduled on the bill Thursday.

Since the legislation was first introduced in April, the pharmaceutical, bio-technology and manufacturing companies have lined up to oppose the key portions of the legislation.

Wednesday, though, that opposition seemed to be lessening.

"The leadership and several members of the committee recognized that changes to the bill are still necessary and we look forward to working with them to further improve the bill," 3M's Gary Griswold, representing the Coalition for 21st Century Patent Reform, said in a statement. "While there is still much work to do before the coalition can support the legislation, we are encouraged by the incremental progress made during today's mark-up."

Griswold added that while the group, which includes Eli Lilly, General Electric, Johnson & Johnson and Proctor & Gamble, still has "serious concerns" about the bill, amendments to it approved Wednesday were a "positive step." The amendments narrow the "second window" of post-grant reviews.

Last week, the Senate Judiciary Committee approved much the same amendments.

According to Sen. Patrick Leahy, infringement damages would be limited, "unless the claimant shows that the patent's specific contribution over the prior art is the predominant basis for market demand for an infringing product or process."

Sen. Arlen Specter (R-Penn.) added an amendment that seeks to eliminate the popular practice of "forum shopping" by limiting venues for patent-infringement cases.

"Few issues are as important to the economic strength of the United States as our ability to create and protect intellectual property," Smith said. "The Patent Reform Act of 2007 updates current law to better protect intellectual property, enhance patent quality and increase public confidence in the integrity of patents."