NEW YORK (CNN/Money) - Drugmakers are pouring billions of dollars into research and development in their quest for the next blockbusters, and analysts have a hard time gauging whether the heavy costs will pay off.

Some of the major drugmakers have ramped up their R&D and have products in their pipelines that could become household names in the near future, industry analysts say. But Barbara Ryan, analyst for Deutsche Bank North America, said it is "virtually impossible" to project the success of a pipeline dollar-to-dollar.

"There is a 10-year lag in R&D spending," said Ryan. "The spending that they're doing today isn't going to be visible in terms of products for quite some time."

Pfizer Inc., the world's biggest drug company with $52.5 billion in 2004 sales, spent $7.6 billion in R&D last year, up 9 percent from 2003, and is expected to spend $8 billion this year boasting an impressive pipeline said John Boris, analyst for Harris Nesbitt.

"We expect from the bounty of long-term data that Pfizer (up $0.13 to $28.80, Research) will be at a competitive advantage," said Boris, who rates the company as a "buy." "You're going to have a very, very robust set of regulatory news on the company going forward."

Lyrica, a Pfizer painkiller approved by the Food and Drug Administration in December, is "one of the diamonds" in the drug industry, said Boris. He expects the drug to reach $2 billion in annual sales by 2010.

Also, Pfizer is expected this year to file Sutent, an orally administered anti-cancer drug, and has anti-cancer drugs Camptosar and Ellence in its late-stage pipeline. Boris said he expects Sutent to reach $500 million in annual sales by 2010. Chris Shibutani, analyst for J.P. Morgan, said in a report that he expects Sutent to reach $500 million by 2009.

Pfizer, which presented Sutent data at the American Oncology Association conference earlier this month, plans to "double its franchise on oncology" over the next five years, to $3.4 billion in 2010 from $1.7 billion in 2005, said Boris.

Steve Lederer, spokesman for Pfizer's R&D department, said that in most cases it is "extremely difficult" to determine the time and money spent on individual drugs because the development process is very complex.

But Lederer said the company expects to spend at least $1 billion developing Torcetrapid, a drug that meant to elevate "good' cholesterol to prevent heart attacks. Torcetrapid is pegged by analysts to be a potential blockbuster, but Lederer declined to provide a sales estimate.

Merck & Co. and Eli Lilly & Co. also have robust pipelines with potential blockbusters, said Ryan of Deutsche Bank, who rates both companies a "hold."

Merck (down $0.19 to $32.35, Research) presented late stage data on Gardasil, a vaccine that prevents cervical cancer and sexually transmitted diseases, on May 19 and the company plans to file for FDA approval this year. Merck has said that Gardasil sales could take the sting out of the loss of Vioxx, an arthritis painkiller pulled from the market in 2003.

Vioxx took in sales of $2.5 billion in 2003, its last full year of sales. Ryan projects that Gardasil, expected to enter the market next year, could bring in $1 billion to $3 billion in annual sales, possibly eclipsing the hole left by Vioxx.

Merck spokeswoman Janet Skidmore said the company has spent 10 years working on Gardasil, but she declined to provide the costs of developing specific drugs.

But Merck faces competition from GlaxoSmithKline, which has a similar vaccine in its pipeline, Cervarix, also meant to prevent sexually transmitted diseases, that could cut into Gardasil sales, said Ryan. Cervarix is one year behind Gardasil in the testing process. (See correction.)

Muraglitazar, a diabetes treatment developed by Bristol-Myers Squibb (down $0.07 to $27.31, Research) and submitted by partner Merck to the FDA, is another blockbuster contender but could face safety concerns and competition from Actos, said Ryan. Actos is a diabetes treatment from Takeda Pharmaceuticals North America. (See correction.)

"We think that Muraglitazar could be a billion-dollar drug because it's oral and it goes into a large patient population," said Ryan. "However, we think that Muraglitazar is likely to face a tough challenge with the FDA. We think there are certainly concerns about side effects and the drug does not appear to be much better than Actos."

Lilly (up $0.52 to $59.22, Research) spent $2.8 billion on R&D last year, up 19 percent from 2003, to help bolster a robust pipeline, Ryan said. Lilly recently launched antidepressant Cymbalta, which could be the company's next blockbuster, according to Ryan, who is projecting $500 million in sales for this year.

"I think Cymbalta will be a billion-dollar drug probably by 2007," said Ryan.

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Correction: An earlier version of the story misidentified the company that produces Actos. Also, Cervarix was mispelled. CNN/Money regrets the errors.

Boris owns shares of Pfizer stock but Harris Nesbitt does not conduct banking with them. Ryan does not own stock but Deutsche Bank may own stock in some of the companies mentioned here.

This story identifies some of the major pharmaceutical products in development but is not a complete list of drug pipelines.