INDIANAPOLIS — A tiny pump injects insulin through a catheter into Bob Russell's abdomen up to seven times an hour, helping him regulate his blood sugar level so he can stay healthy.

The 53-year-old diabetic from suburban Indianapolis used needles to inject himself with insulin until five years ago, when doctors gave him the pump he calls a "godsend."

"It's really simplified my life," said Russell, who was diagnosed as an insulin-dependent diabetic 23 years ago.

Now he's hoping to trade the pump for an inhaler, one of a series of new drugs aimed at a population of diabetics that experts predict could double, to 350 million, in the next 20 years.

Drug companies are racing to capture that ballooning market as health advocates worry the disease will become a public health threat. Pfizer Inc. plans to debut Exubra, its new inhaled insulin treatment, in July, and Merck & Co., Novartis AG and Eli Lilly and Co. are awaiting FDA approval for new diabetes products that could generate hundreds of millions of dollars in sales.

"I think it's intensely competitive," said John C. Lechleiter, president and chief operating officer of Indianapolis-based Lilly, which began offering Byetta, an injectable diabetes treatment last year. "Many companies that would not have said they were engaged in diabetes research 10 years ago are squarely there now," he said.

Albert Rauch, a health care analyst with A.G. Edwards & Sons, said he expects the $10 billion diabetes market to eventually rival the $20 billion cholesterol market. "We think they could be the next blockbuster class of drugs for the pharmaceutical industry," he said.

But the companies could have trouble getting their newest medications into patients' hands.

Gun-shy physicians — many of whom are still reeling over fallout from Vioxx, a blockbuster arthritis drug that was pulled from the market after it was linked to increased risk of heart problems — want more research about potential long-term health problems. And insurers could be slow to add some of the latest diabetes drugs to their preferred drug lists.

"It's safe to assume that unless Exubra is priced comparatively to insulin, it would not be added," said David Beshara, chief pharmacy officer for Tennessee's Medicaid program.

Robert Seidman, vice president and chief pharmacy officer for the Indianapolis-based WellPoint Inc., the nation's largest insurer, said a medication usually is on the market six months before a panel of company experts reviews it to decide whether to add it to its preferred drug list. "The science needs to drive the decision-making process," he said.

Health advocates say the need for new treatments is clear.

A study released this month by the American Diabetes Association said one in three Americans has diabetes or a precursor to the disease, which causes elevated blood sugar levels. Untreated, diabetes can be fatal or cause blindness and circulation problems.

More than 90 percent of patients are diagnosed with Type 2 diabetes, a condition linked to obesity that occurs when the body cannot effectively use the insulin it produces. Fewer than 10 percent of patients are diagnosed with Type 1 diabetes, a disorder in which the immune system attacks insulin-producing cells in the pancreas.

The disease could yield billions of dollars for pharmaceutical companies.

"Whenever there's a great commercial opportunity, companies devote more resources," said Barbara Ryan, an analyst at Deutsche Bank."

In December, Whitehouse, N.J.-based Merck announced it was retooling its business to focus on nine key growth areas — including diabetes and obesity.

The company is awaiting FDA approval for Januvia, a new class of oral diabetes drug that enhances the body's ability to lower elevated blood sugar levels. Later this year, Merck also expects to file an application for MK-431A, an unnamed drug that combines Januvia with the common diabetes medication metformin. The combination would allow patients to take fewer pills each day.

"We believe there's a tremendous unmet medical need for patients with Type 2 diabetes," said John Amatruda, vice president of clinical research of metabolic disorders at Merck.

Analysts predict Januvia sales could reach $1 billion in 2009.