Inhaled insulin may be associated with lung cancer

Drug company updated product labeling to include new warning.

Clinical trial data has revealed increased reports of lung cancer among patients using inhaled insulin, which prompted Pfizer to update its product labeling for the therapy.

The data demonstrate that six of 4,740 patients treated with the inhaled powder form of recombinant human insulin (Exubera, Pfizer) developed lung cancer, compared with one of 4,292 patients not treated with the therapy. One inhaled insulin-treated patient also reported primary lung malignancy in a post-marketing report.

The “Warnings” section update now states that all patients who developed lung cancer had a previous personal history of cigarette smoking. The update also says that there are too few cases to determine whether the development of lung cancer is related to use of inhaled insulin.

“Some patients continue to take Exubera, including those enrolled in extended transition programs or clinical trials. We are working closely with patients and their physicians to ensure the continued orderly transition from Exubera to alternative therapies,” Joe Feczko, MD, chief medical officer of Pfizer, said in a press release.

For reasons unrelated to this data, Pfizer said it would stop marketing its inhaled insulin in October. In the meantime, physicians should seek alternative therapies to maintain patients’ glycemic control, because of the limited availability.

The clinical trial data released by Pfizer has also prompted biopharmaceutical company Nektar Therapeutics to announce that it will terminate negotiations with potential partners for inhaled insulin.

"The concern over this new data analysis from ongoing clinical trials has resulted in the termination of all negotiations with potential partners. Fortunately, over the past year Nektar has significantly transformed its business, moving away from inhaled insulin," Howard W. Robin, president and CEO, said in a press release. – by Katie Kalvaitis

Since insulin is a growth factor, endocrinologists have always been concerned that inhaled insulin would be associated with lung cancer. Because of this and in spite of earlier assurances from clinical trials that there was no such increase in the risk of lung cancer, many endocrinologists, like myself, have never prescribed inhaled insulin. Obviously, our worst fears have been realized. This is the final nail in the inhaled insulin coffin.

– David S. H. Bell, MD

Endocrine Today Editorial Board member