The only thing worse for a pharmaceutical company than generic competition is generic competition that it didn't prepare for. Such was the case for Wyeth (NYSE: WYE) in the first quarter as it scrambled to deal with generic competition from Teva Pharmaceuticals (Nasdaq: TEVA) against its heartburn drug Protonix, which Wyeth believes is still under patent.

Fortunately, Wyeth seems to be managing quite well. Sales of former blockbuster drug Protonix plummeted 66%, but Wyeth still managed to increase its revenue by 6% year over year. There's still potential for Wyeth to win in court, where it could not only gain the lost Protonix sales back, but also recover triple damages. The trial isn't expected to begin until the middle of next year.

The revenue growth was spurred on by antidepressant Effexor, which rose 15%, and rheumatoid arthritis drug Enbrel, which jumped 36% to $606 million outside North America. Amgen (Nasdaq: AMGN) and Wyeth co-market the drug in the U.S. and Canada. All the arthritis drugs are doing quite well with this year, with Johnson & Johnson's (NYSE: JNJ) Remicade and Abbott Labs' (NYSE: ABT) Humira both posting double-digit percentage gains. Maybe the baby boomers are hitting the magical age for getting arthritis?

While Wyeth was able to keep the top line up, it failed to trickle through to the bottom line. Profits fell more than 4% as the company had higher expenses and a charge primarily for laying off all those workers from its cost-cutting program.

Looking forward, a couple of upcoming events could drive Wyeth's stock price. Next week the company should hear back from the FDA about its opioid-induced constipation (OIC) drug, which it will market with Progenics Pharmaceuticals' (Nasdaq: PGNX). The drug recently failed as a treatment for postoperative ileus (POI), but it still has a good chance of being approved this month for OIC.

Investors should also be on the lookout for phase 2 data for Alzheimer's treatment bapineuzumab in the middle of this year. Wyeth and its partner Elan (NYSE: ELN) have already begun a phase 3 trial of the drug based on the interim results from the phase 2 trial, so anything less than stellar results may be a letdown.

Wyeth is looking for adjusted EPS of $3.35 to $3.49 this year, which might fall just shy of last year's number. Given the loss of exclusivity for one of its main drugs, that sounds like a win in my book.

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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. The Fool has a disclosure policy.