What happened

Allergan's (NYSE:AGN) stock slid by double digits for the third straight month in October. So after dropping by another 13.5% last month, Allergan's stock has now lost around 30% of its value since the start of August, according to S&P Global Market Intelligence

The drugmaker's woes stem from two core issues:

  • The potential entrance of generic competitors for the dry-eye medication Restasis in 2018. Restasis is currently Allergan's second best-selling medicine behind Botox. 
  • Allergan's hefty stake in Teva Pharmaceutical Industries that continues to lose value month after month. 
A man staring at an arrow that has broken through the floor.

Image source: Getty Images.

So what

Like most large-cap pharmas right now, Allergan is going through a product refreshment cycle, whereby newer growth products pick up the slack from a revenue standpoint for older medicines that have lost -- or are about to lose -- patent protection.

The market doesn't seem all that optimistic about Allergan's late-stage clinical pipeline, especially since the drugmaker sports a fairly substantial amount of debt, in excess of $30 billion, that may keep management from pursing a bolt-on acquisition in the event of a major clinical setback.  

Now what

At a forward price-to-earnings ratio of 10.35, however, Allergan comes off as an absolute bargain at current levels, despite these headwinds. That being said, the market seems to be forecasting an unexpectedly sizable dip in the company's earnings next year -- presumably as a result of Allergan's failure to protect Restasis' patent portfolio.

As a reminder, Allergan's management attempted to extend the drug's period of exclusivity through a controversial licensing deal with a Native American tribe, only to have a federal judge invalidate Restasis' patents altogether last month. As such, the door is now wide open for generic competitors, and that could take a toll on Allergan's top line next year, assuming the U.S. Food and Drug Administration approves a generic soon.

At the end of the day, Allergan's chances of rebounding rest squarely on the fate of its late-stage clinical pipeline. If things go smoothly, Allergan does have a number of high-value clinical assets that could change its outlook in a hurry. But then again, clinical trials in general are never a sure thing, making it particularly hard to decipher if this falling knife is indeed worth buying right now. Investors, therefore, may want to tread lightly with this potential value stock for the time being.