Pfizer Warns of Lung Cancer with Inhaled Insulin

Pfizer (New York, NY, USA) and Nektar Therapeutics (San Carlos, CA, USA) have announced that clinical trials of the inhaled insulin Exubera found increased cases of lung cancer, leading Nektar to stop seeking a marketing partner for the troubled product and abandon it.

Exubera, a powdered form of recombinant human insulin, is delivered through an inhaler into the lungs where it is absorbed. Once it has been absorbed, it begins working within the body over the next few hours. Diabetics still need to take a longer-acting basal insulin via injection. Clinical trials concluded that inhaled insulin appears to be as effective, but no better, than injected short-acting insulin. However, over the course of these trials, six of the 4740 Exubera-treated patients versus one of the 4292 patients not treated with Exubera developed lung cancer. All patients who developed lung cancer had a history of cigarette smoking, but too few cases existed to determine whether the development of lung cancer was related to Exubera use. One lung cancer case was also found after Exubera reached the market. Pfizer said it would be discussing withdrawals of marketing authorizations for Exubera with the U.S. Food and Drug Administration (FDA) and other regulatory agencies.

The lung-cancer disclosure dealt a final setback to Exubera, once projected by Pfizer to be a U.S. $2 billion-a-year blockbuster drug. However, despite high hopes for Exubera, it generated few prescriptions; the medicine was dogged by concerns about lung safety and about the inconvenience of the bulky device used to administer the product. Pfizer said in October 2007, it would stop marketing Exubera and return the rights to Nektar. Since then, other manufacturers, such as Eli Lilly (Indianapolis, IN, USA), have also ended inhaled insulin development programs.

"We made an important decision regarding Exubera, a product for which we initially had high expectations,” said Jeff Kindler, Pfizer's CEO. "Despite our best efforts, Exubera has failed to gain the acceptance of patients and physicians.”

Nektar Therapeutics has announced it will cease all spending associated with its inhaled insulin programs, including a next-generation version in early clinical testing.


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