The bid to create a legislative pathway for FDA approval of follow-on biologic drugs -- sometimes misleadingly referred to as generic biologics -- got a major boost on June 23rd when a bipartisan group of Senators announced they had hammered out compromises on the key provisions.

The draft compromise bill resolves such contentious issues as the extent of trials a follow-on biologic would need prior to approval, whether a biosimilar could be deemed an interchangeable alternative to a brandname biologic, and the length of time an innovator biologic would be protected from competition.

As a result, the compromise legislation to pave the way for regulatory approval of sale of biosimilars in the United States will be voted on -- and likely approved -- by the Senate Health, Education, Labor and Pensions Committee when it meets on June 27th.

The bill's future after that, however, remains in considerable doubt. Sen. Edward M. Kennedy (D-MA), chairman of the Senate panel, has promised to seek to have follow-on biologics provisions included in a major Food and Drug Administration funding bill that passed the Senate last month.

However, the White House has registered opposition to inclusion of biosimilar provisions in the "must-pass" Prescription Drug User Fee Act, and House leaders have neither reached their own agreement on biosimilars or acted on the FDA funding legislation..

That leaves it highly uncertain that Senate language on follow-on biologics will make it all the way through Congress this session, but the compromise significantly increases prospects of enactment of a pathway for approval of biosimilars prior to next year's presidential election.

Pressure for Congressional action that would enable the FDA to approve alternatives to innovative biologic drugs stems from the fact that these drugs -- used to treat a growing variety of serious conditions -- are the fastest-growing component of America's soaring healthcare costs.

Proponents would like to see follow-on biologics approved in the belief that, like generic chemical drugs, they would bring down biologic costs when patent protection on a brandname drug expieres.

But the biopharmaceutical industry argues it is next to impossible to make exact duplicates of biologic drugs, which are grown in specially engineered cells and have a high molecular complexity, and say follow-on biologics should be subjected to the same testing and trials as the original drug.

The compromise bill stakes out a middle ground on this issue. It provides that a company which wants to market a biosimilar product must do animal studies and one human study, but also gives the FDA the power to waive the requirement on a case-by-case basis.

On an issue important to the generic industry, the compromise allows for the possibility of "interchangeability," meaning some biosimilars could potentially be automatically substituted for the original branded medicine.

But the compromise also contains a provision important to biopharmaceutical companies that invest heavily in developing new biologics: a guarantee of 12 years of exclusivity before a follow-on version could be brought to market.

"Congress has a responsibility to encourage the innovation that leads to these new medical miracles, and to see that they are affordable for the patients who need them," Kennedy said in a statement.

"Our bipartisan legislation also includes strong and responsible incentives to encourage dynamic new biotechnology companies to invest in the innovations that will produce the cures of tomorrow," he added.

"It's crucial that Congress get this right because biologics are the future of medicine,'' Hatch said in a statement. "It's taken a lot of effort, but we've achieved a good balance in this bill."

The draft legislation can be viewed by clicking here.