As I predicted, approvals for generic equivalents to biotech drugs are heating up in Europe. On Thursday, the   European Medicines Agency's (EMEA) Committee for Medicinal Products for Human Use (CHMP) announced positive opinions on biosimilars from three companies.

The products from Teva Pharmaceuticals (Nasdaq: TEVA), ratiopharm, and CT Arzneimittel are all generic versions of Amgen's (Nasdaq: AMGN) Neupogen, a drug that stimulates production of white blood cells in cancer patients.

The trio joins Novartis (NYSE: NVS) and Hospira (NYSE: HSP), which already have approved biosimilar versions of Johnson & Johnson's (NYSE: JNJ) Eprex, which stimulates production of red blood cells.

Are you seeing a pattern here? There are a couple of reasons that the generic-drug companies are going after these blood stimulating products. They've been used for quite a while, which probably makes obtaining EMEA approvals easier. Perhaps more important, there's a pretty decent-sized market for these products. According to Teva, sales of Neupogen in the E.U. are about $300 million per year.

That's no small potatoes, but compare it to the $860 million in U.S. sales that Neupogen had last year and you can see why generic drug companies want Congress to get moving on their proposed plan to establish a pathway for the FDA to approve biosimilar products.

My guess is that it won't happen until after the presidential election, but now is the time for investors to figure out who will be the main players when the U.S. opens its doors to biosimilar products.

With its purchase of CoGenesys and recent positive recommendation from CHMP, Teva is making a play at becoming the leader in biosimilar products, as it is in pharmaceutical generics.

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Johnson & Johnson is a selection of the Income Investor newsletter service. The Fool has a disclosure policy.