NEW YORK (CNN/Money) - Pfizer CEO Henry McKinnell got grilled by industry analysts Thursday after the world's biggest drugmaker pulled its financial guidance for 2006 and 2007.

"We share some of your disappointment in some of the news reported today," said McKinnell. "Beyond the quarterly numbers, we ask you to look at the greater picture of a Pfizer in transition."

Net profits tumbled 52 percent at Pfizer (Full story).

And while its operating profits actually topped Wall Street forecasts, the New York-based company pulled earnings guidance for 2006 and 2007, sparking analysts to press McKinnell and other Pfizer executives several times Thursday for more information about the company's prospects.

"It was not your typical Pfizer conference call," said Al Rauch, analyst for A.G. Edwards who rates Pfizer a "hold." "I think some of the analysts were a little concerned."

Executives said new guidance numbers would be released early next year.

Pfizer (down $2.07 to $21.90, Research) stock tumbled 8.4 percent to its lowest level in eight years in heavy New York Stock Exchange trading. Volume was about four times the stock's normal daily average.

The decline in Pfizer, one of 30 stocks in the Dow industrials, weighed on the broader market (Full story).

Deutsche Bank analyst Barbara Ryan wrote in a report Thursday that Pfizer's withdrawal of earnings guidance left "maximum uncertainty regarding the company's future outlook."

Robert Hazlett, analyst for Suntrust Robinson Humphrey, said, "It's not very confidence inspiring to pull your guidance, and because of that we're looking hard at our 2006 estimates."

But Hazlett is maintaining his "buy" rating and said he is "hopeful that this is the worst of it." He said that Pfizer needs to recover losses with "invigorated" Lipitor revenue and sales from recently released Lyrica, a painkiller, as well as insulin inhaler Exubera and anti-cancer drug Sutent, which have been filed with the FDA.

McKinnell also pointed to these three products as potential bright spots in future earnings. The CEO and other executives attributed the earnings drop to a 44 percent slump in sales of Celebrex, a painkiller belonging to the same drug class as Pfizer's Bextra and Merck's Vioxx, both withdrawn from the market because of health concerns.

Pfizer executives also cited patent litigation battles and generic competition as barriers to earnings growth.

Pfizer Vice Chairman Karen Katen said that Lipitor, a cholesterol-lowering medicine and the world's top-selling prescription drug, was a "major driver" for company earnings. Pfizer reported a 6 percent rise in Lipitor sales for the third quarter.

In his remarks, McKinnell cited the "uncertainties" of "a Pfizer in transition" but said the company's plan to slash $4 billion in costs, partly through plant closings, would help alleviate its problems.

He said the company was ensuring future earnings by building up its pipeline, citing its recent acquisition of drugmaker Vicuron.

But this did not reassure analysts.

Deutsche Bank's Ryan, for one, cut her price target to $27 a share from $33. "While extraordinarily disappointed with today's news, we see no point in adding insult to injury at this price and are maintaining our 'buy' rating," she wrote in a note to clients.

A.G. Edwards' Rauch said that Pfizer can do little more than replace lost revenue until 2008, when it puts behind its $10 billion worth of lost sales from expired patents.

"You just can't grow the top line," said Rauch. "I view Pfizer as a duck. They're floating and it looks easy, but they're paddling like crazy underneath."

Rauch has a family member who owns Pfizer stock, and Rauch's firm, A.G. Edwards, is also affiliated with a company that conducts business with Pfizer. Hazlett does not own Pfizer stock, but his firm is affiliated with a company that conducts business with Pfizer. Ryan does not own Pfizer stock, but Deutsche Bank may have done business with Pfizer within the last 12 months.

To read more about Pfizer's third quarter earnings, click here.