| Exubera isn't really a drug, it was a method of delivery of insulin, a hormone the pancreas produces to regulate glucose levels. It's a rather necessary hormone, and replacement of that hormone is essential for type 1 diabetics.
With the numbers given in the article, it's quite a leap to say with any certainty that the method of delivery has caused the lung cancer in the cases of those who developed lung cancer. There are many causes of lung cancer. But there were enough cases that Pfizer needed to put warnings on the remaining production of Exubera, which is to be discontinued anyhow because there probably isn't as large of a market for inhaled insulin as the pharmaceuticals seem to think there is and Exubera's method of delivery using the huge bongpipe along with the packets didn't result in a stampede of diabetic patients asking their doctors for RXes. | 
