Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Momenta Pharmaceuticals (NASDAQ:MNTA) are trading up 11% after moving higher all day following news released after yesterday's close that Teva Pharmaceuticals (NYSE:TEVA) has lost its bid to block generic versions of Copaxone from hitting the market.

So what: Copaxone, which treats multiple sclerosis, is Teva's biggest blockbuster and its best cash cow, but its patent will expire in less than two weeks. Other drugmakers have been eagerly waiting in the wings with generic formulations. Momenta is one of these competitors, and is expected to roll out its generic Copaxone by the end of the month now that all legal roadblocks have been removed.

Now what: Copaxone brought Teva roughly $4.3 billion in sales last year, and gaining a mere 10% of those sales (with a much higher share of the drug's total sales, of course) would increase Momenta's annual revenue more than tenfold.

Momenta shares have been been zig-zagging for years as investors wait for the company to get something out there, and its Copaxone generic should, at the very least, give it a stronger revenue stream. However, it's a bit early to predict just how much stronger that revenue stream will be. Dig a little deeper to see if Momenta finally has the momentum you need from your biotech investments.

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Alex Planes has no position in any stocks mentioned. The Motley Fool recommends Momenta Pharmaceuticals and Teva Pharmaceutical Industries. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.