Saturday, February 02, 2008
On the other hand, there are examples where a drug is developed as a me-too or me-three drug, and surprises everybody. An example in the diabetes field: Actos (pioglitazone) is the last man standing in the class of drugs called thiazolidinediones or glitazones, as the other two glitazones, Rezulin (troglitazone) and Avandia (rosiglitazone) have come under the regulatory microscope because of side effects: Rezulin was withdrawn because of liver problems, and Avandia has been under fire for cardiac problems; to date, Actos has had much less problems. Thus, relative safety may become a selling point for a me-too/me-three drug.
And in the hyperlipidemia treatment arena, there were quite a few statins on the market when Parke-Davis released Lipitor (atorvastatin) to a less-than-rousing reception -- as I vaguely recall, Lipitor was approximately a me-six statin; there are at least nine out there presently. But within a year of its release, Lipitor was noted to have spectacular efficacy compared to the other statins, and soon became described as a "superstatin." Sales took off, Pfizer bought Parke-Davis to get Lipitor, and Lipitor jumped to the head of the class -- indeed the most profitable drug overall: according to the Wall Street Journal, with 2006 sales of 12.9 billion dollars, it is the largest selling drug in the world. Hence, improved efficacy may also become a selling point for a me-too/me-three drug.
So don't be surprised that drug manufacturers keep coming up with me-too and me-three drugs. It's profitable to do so, and sometimes one of these drugs goes to the head of the class. And even if it doesn't, the second/third/etc. drug may add to the bottom line, and sometimes has better efficacy, and sometimes better safety. It's a gamble the drug industry will happily take.
