The war on cancer has some fortified soldiers. Some of the nation's biggest drug companies are investing an increasing amount of resources toward finding treatments for the disease.

Cancer research has been a hallmark of companies such as Bristol-Myers Squibb Co. and AstraZeneca PLC. But over the last few years, others including Wyeth, Schering-Plough Corp., GlaxoSmithKline PLC and most notably Merck & Co. have been intensifying their work on cancer medicines. They've purchased smaller, cancer-focused drug makers; formed licensing arrangements; added staff and created specialized research centers.

The increasing commitment to cancer treatments grows out of a confluence of economic and scientific factors. Company executives say the odds of finding suitable drug candidates have risen significantly in the last few years with the mapping of the human genome and other technological advances. And new cancer treatments can command very high prices and generate substantial revenue, since there is little competition in the field.

Novartis SA's Gleevec, introduced in 2001, treats a form of leukemia (search) as well as rare tumors of the gastrointestinal tract. It costs about $2,450 a month wholesale per patient, and brought in $1.6 billion in sales last year. Erbitux, a treatment for colorectal cancer introduced last year by Bristol-Myers and ImClone Systems Inc., carries a wholesale cost of between $18,000 to $40,000 a month per patient. Analysts predict Erbitux will also be a blockbuster.

Insurance typically covers the cost of treatment, but there's still been controversy over some cancer drugs' cost. Companies have programs for patients who lack insurance and can't afford the drugs. Still, those prices create an attractive market.

"Drug companies are seeing that cancer can be lucrative," said David Moskowitz, an analyst with Friedman, Billings, Ramsey. "Look at Erbitux and Gleevec. They may be for small markets, but the prices will let the companies make money."

Whether the increased investment will lead to a rash of new cancer products remains to be seen. Drug development is still a risky business; cancer accounts for the second-largest part of Pfizer Inc.'s research budget but that hasn't transformed the company into a powerhouse in that area.

Pfizer does have a promising product for patients with the same rare tumors treated by Gleevec but who have become resistant to that drug. The company may file for federal approval of the drug later this year. Bert Hazlett, an analyst with Suntrust Robinson Humphrey, said the drug's sales potential could reach $800 million to $1 billion if it is approved for other types of cancer.

Wyeth has a product for kidney cancer it intends to seek approval for next year. Meanwhile, Novartis SA plans to seek approval for a drug for colorectal cancer either late this year or in early 2005. Merck, always a force in the vaccine industry, has an inoculation for cervical cancer that it plans to seek approval of this year.

"There has just been an explosion of our understanding of cancer since human genome," said Dr. Lee F. Allen, vice president of oncology clinical research at Wyeth, which currently sells two cancer drugs.

Two and a half years ago, Wyeth created a center of excellence to research cancer, placing everyone working on the disease in Cambridge, Mass. This allowed the group to streamline its approach and work with the academic community in the area. It currently has 13 cancer drugs in clinical development, triple the amount from three years ago.

When GlaxoSmithKline was formed through a merger in 2000, the company had two cancer drugs. Now, with a new focus and additional spending, the company is developing eight drugs for cancer treatment, plus three for the treatment of side effects, one vaccine and three therapeutic vaccines.

Perhaps the most pronounced efforts are at Merck, which doesn't sell any cancer treatments although it does have Emend, a product for nausea caused by chemotherapy. In the last 18 months, Merck purchased Aton Pharma Inc., a privately held biotech company focused on cancer treatments, and it has signed deals with two smaller companies to develop oncology drugs.

A deeper understanding of cancer and advances in technology have contributed to the shift in drug companies' focus, said Dr. Stephen H. Friend, Merck's executive vice president of advanced technology and oncology.

"Now we have the tools that allow us to see what is going in cancer cells," Friend said. "We've gone from uncertainty about the disease to having more clues about what we can do."

Friend says it is possible to scan an entire cancer cell to look for specific mutations that provide researches an idea of which compounds might be most effective in treating the disease. Such tools mean it can take just two to five years to bring a compound into clinical development, down from 5 years to 10 years just a few years ago.

Such improvement brings business benefits. Industry experts say it costs over $800 million to develop a drug. Hastening the development process will reduce costs. That's especially important for cancer drugs because they have smaller markets than other diseases; there are many more people who suffer from high blood pressure, for example, than there are people with most types of cancer.

Cancer drug development already has some economic advantages — trials are usually shorter and require fewer patients than drugs to treat other conditions. For example, Pfizer's Phase III trial for its promising cancer drug contained less than 400 patients. A typical Phase III study has between 1,000 and 5,000 patients.

The Food and Drug Administration also has expedited approval of drugs for cancer and other diseases life-threatening with less clinical testing than typically required. The companies do have to continue to study the drugs after approval.

Another advantage to selling cancer drugs is that the smaller patient populations allows for more targeted marketing, "The marketing is less expensive because it is more focused," said Dr. Joerg Reinhardt, head of development at Novartis.