Exubera, the first and so far only commercially available inhaled-insulin diabetes treatment, is on the verge of turning into an expensive flop for its maker, Pfizer.
At one point, the company regarded the drug as a potential blockbuster. But despite six months of marketing to doctors, Exubera receives only about one of every 500 prescriptions for insulin written in the United States.
A new diabetes pill, Januvia, which is made by Merck and was approved after Exubera, is already prescribed about 40,000 times a week in the United States, 25 times as often as the Pfizer drug.
And so Wall Street analysts are cutting their sales estimates for Exubera, which has been dogged by questions about its safety, cost and convenience.
Pfizer says it has not given up on Exubera and last week started a new marketing campaign to persuade doctors to prescribe the medicine. In January, the company projected that despite its slow start Exubera would eventually achieve worldwide sales of $2 billion. But doctors and analysts are skeptical.
"I don't think the drug can be saved," said David Risinger, an analyst at Merrill Lynch, who last week cut his estimates for Exubera sales. Risinger now expects that Exubera will have $310 million in sales worldwide in 2012, down from his previous estimate of $800 million. Other analysts have also cut their forecasts.
Exubera's problems add to the uncertainties facing Pfizer, whose shares have lost almost half their value since 2000. While the company remains very profitable, its health is increasingly tied to Lipitor, a best-selling cholesterol-lowering medicine that faces competition from cheaper drugs and in several years, patent expiration.
In interviews yesterday, Pfizer executives acknowledged Exubera's problems but said they believed that a new sales push would spur the drug's sales. The company will work to convince doctors that insulin, in both inhaled and injectable forms, is underprescribed. And this summer, Pfizer plans to begin directly advertising the inhaler to patients.
"Sales have been slower than expected," said Olivier Brandicourt, general manager for Pfizer's metabolic and cardiovascular division, which includes Exubera. "It takes time to educate the physician."
Rochelle Chaiken, Pfizer's vice president for global medical affairs, said almost 60 percent of diabetes patients had overly high blood sugar levels despite being on standard oral diabetes medications. Many of those patients should be taking Exubera, she said.
But Pfizer's marketing may not be enough to overcome the medical, economic, practical and legal concerns that have hurt Exubera. In theory, the drug's biggest advantage over standard injectable insulin is that it is more convenient and does not require needle pricks.
In reality, though, the Exubera inhaler is bulky and can be hard to use, doctors say. The device is nearly as large as a tennis ball can when it is open, and must be repeatedly pumped before the insulin can be inhaled. Making matters worse, Exubera comes in different doses from standard insulin, and converting doses can be complicated, the doctors say.