Valeant Pharmaceuticals (VRX) stock did a face-plant this week after allegations were made of shady revenue accounting and financial nondisclosures.

Although Valeant disputed the claims, the stock's free-fall dragged down a bunch of other big drug stocks, including Pfizer (PFE) - Get Pfizer Inc. Report , Bristol-Myers Squibb (BMY) - Get Bristol-Myers Squibb Company Report , Eli Lilly (LLY) - Get Eli Lilly and Company (LLY) Report and AbbVie (ABBV) - Get AbbVie, Inc. Report .

Whether the allegations against Valeant are true or not, they shouldn't be tainting most other biotech and drug stocks. That's because Valeant is in its own unique universe.

Valeant includes the word "Pharmaceuticals" in its name, but its business model is far different from what most people think of when they think of drug companies; i.e., a science-based, research-focused business aimed at developing new drugs.

In contrast, Valeant pours almost no money into drug research. Instead, it grows by acquiring smaller drug companies, then stripping away costs, firing employees, and raising the prices of the drugs which remain. It's the classic roll-up business strategy, turbocharged by Valeant's Canadian domicile, which lowers its tax burden and maximizes profits.

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Wall Street loved Valeant because it offered investors exposure to the lucrative drug industry without requiring them to get bogged down in the risk business of clinical drug development. Valeant was all about the numbers, which a lot of investors are much more comfortable with than they are with biology and medicinal chemistry.

I'm using the past tense to describe Wall Street's love affair with Valeant because the mood has definitely soured this week. Valeant is holding a conference call Monday during which it will try to defend its business model against the accusations that its revenue accounting practices harken back to the dark days of Enron.

On Thursday night, PhRMA, the drug industry's trade group in Washington, D.C., published a blog post on its website criticizing Valeant's business strategy as "more reflective of a hedge fund than an innovative, biopharmaceutical company." In a further insult, the PhRMA blog post likened Valeant to Turing Pharmaceuticals, vilified by just about everyone for its rapacious price increase for an infectious disease drug.

I shudder at the thought of agreeing with drug industry lobbyists, but their point about Valeant being a bad actor operating out of bounds is a good one. This doesn't relieve biotech and drug companies from dealing with problems of their own, but they're not Enrons.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.