WASHINGTON (Reuters) - Drug regulators gave the nod to a Teva Pharmaceutical Industries drug that boosts the production of infection-fighting white blood cells in certain cancer patients receiving chemotherapy.
Teva's medicine is similar to Amgen Inc's biologic drug Neupogen, which faces the expiration of its U.S. patent next year.
"While approval at this time is somewhat unexpected, we note the two drugs are not substitutable, and it will require a launch ramp and extensive marketing efforts by Teva to gain share," RBC Capital Markets analyst Michael Yee said in a research note.
Amgen's U.S. sales of Neupogen were $959 million last year, while sales of Neulasta, the biotech company's longer-lasting white blood cell booster, were $3 billion.
In a settlement of patent litigation, Teva agreed last year to refrain from launching its versions of both drugs in the United States until November 2013.
"Teva is prohibited by court order from marketing this product in the U.S. prior to November 10, 2013," Amgen said in a statement.
Teva already sells its version of Neupogen, or filgrastim, in the European Union, where Yee said it accounts for about 5 percent of the overall market.
The U.S. Food and Drug Administration said Teva's drug, called tbo-filgrastim, stimulates bone marrow to increase production of white blood cells, which may help cancer patients recover more quickly from the side effects of chemotherapy.
Biotech drugs, which are derived from living matter such as proteins, are usually given by injection. The innovative drugs - first introduced in the 1980s - can cost tens of thousands of dollars a year. Copying them is much more complicated, and expensive, than duplicating conventional chemical-based compounds.
The FDA earlier this year issued draft guidelines governing the process for review and approval of drugs deemed interchangeable with original biotech products.
But the final rules remain uncertain and many generic drugmakers, such as Israel-based Teva, are pushing forward with biosimilar drugs using the FDA's standard drug approval process.
As global pharmaceutical companies face the loss of patent protection on many established drugs, U.S. sales of biosimilars are expected to reach $1.9 billion to $2.6 billion by 2015, according to IMS Health.
(Reporting by Anna Yukhananov; Additional reporting by Bangalore equities newsroom, and Deena Beasley; Editing by Dan Grebler and Steve Orlofsky)