Federal legislation that would expedite the arrival of generic versions of biotechnology drugs onto the market has stirred up controversy in the Senate and among the nation's biotech firms.

Senators Charles Schumer, a Democrat from New York, and Susan Collins, a Republican from Maine, have introduced legislation that would limit the exclusivity period for patents by allowing the Food and Drug Administration to approve generic versions of drugs five years after the original brand-name patent was granted.

Right now, the FDA is restricted from approving generic forms of biotech drugs, a classification of pharmaceuticals that are developed by manipulating proteins that make up human DNA.

The bill would also allow the FDA to determine on a case-by-case basis whether generic drugs require additional testing before being marketed.

House Energy and Commerce Committee Chairman Henry Waxman, a Democrat from California, introduced a similar bill in the House two weeks ago. Legislation reducing market exclusivity passed the Senate Health, Education, Labor and Pensions Committee last year, but was never heard on the floor.

The measure is opposed by Sen. Edward Kennedy, a Democrat from Massachusetts, whose support is considered vital to the bill's success because of Kennedy's long history hammering out agreements between the FDA and private companies.

A Kennedy aide has stated that the Senator would approve a 12-year exclusivity period.

Members of the biotech community also have criticized the legislation, stating that it could lead to the sale of unsafe drugs. Biotech advocates also worry the legislation could undermine the industry's ability to develop future therapies, which are largely funded by earnings made on a company's marketed drugs.  

President Obama, who has emphasized the need for generic competition in the drug industry, is expected to support the measure.