Sen. Edward Kennedy, in a break with the White House, on Tuesday submitted a proposal that gives brand-name pharmaceutical companies an opportunity for more than 12 years of exclusivity before generic versions of biologic drugs can reach the market.

The proposed bill would give brand-name makers of biologics, complex and expensive medicines derived from living cells, at least 12 years to market their drugs before competitors could begin selling cheaper versions similar to generics. Depending on the innovations made to a given drug, companies could get up to 13-and-a-half years of exclusivity.

The proposal will be amended substantially and may even be replaced, according to a senior congressional aide.

The industry has lobbied hard for 12 years of exclusivity, saying that anything less would kill innovation. A handful of executives from brand-name pharmaceutical companies, including Abbott Laboratories (ABT) and AstraZeneca PLC (AZN), met with White House health care officials earlier Tuesday morning to lobby hard on the "very critical issue," said Billy Tauzin, president of the industry's main lobby, PhRMA.

The Obama administration has said it supports seven years of exclusivity, while the sponsors of bills in the Senate, and a separate bill in the House, would allow for five years of exclusivity.

Kennedy, D.-Mass., is chairman of the Senate Health, Education, Labor and Pensions Committee. Members of the committee have until tomorrow night to file amendments. Sen. Sherrod Brown, a Democrat from Ohio, has already filed an amendment that would lower the exclusivity to seven years.

Kennedy has long supported giving brand-name pharmaceutical companies 12 years of exclusivity.

However, some say the current proposal makes an inexplicable break with earlier promises he made to keep the exclusivity to 12 years, not to allow brand-name companies the opportunity to get 13.5 years.

"Why on earth is Kennedy going from 12 to 13 and a half?" said Katie Huffard, executive director of the Coalition for a Competitive Pharmaceutical Market, or CCPM. CCPM supports proposals that give fewer years of exclusivity.

-By Jared A. Favole, Dow Jones Newswires; 202.862.9207; jared.favole@dowjones.com