A Brief History of Cialis

Since the March 27th 1998 FDA approval of the prescription drug Viagra, Pfizer, enjoyed a five plus year monopoly of being the only prescription drug company that could distribute the erectile dysfunction drug Sildenafil Citrate. And as such sold over 1 billion dollars worth of the drug in just the first year of introduction. This finally changed on August 19, 2003  with the FDA approval of Levitra and November 21, 2003 FDA approval of Cialis.

The development of the impotence prescription drug Cialis has an interesting beginning. The drug company Icos actually began studies on a PDE5 enzyme inhibiter called IC351 in 1993. This is the process by which all erectile dysfunction drugs work. Interestingly enough, in 1994 scientist for Pfizer discovered that  Sildenafil Citrate caused heart patients to get an erection during clinical studies of the heart medicine.

One can only assume that testing that was being conducted for the chemical compound IC351 was not being tested for erectile dysfunction. Little did they know that the compound that was similar in effect to Sildenafil Citrate, just one year later would be discovered as a potential impotence medication by another drug company, Pfizer.

The Bothell, Washington-based company, Icos, that began operations in 1990, received its first patent on IC351 in 1994.  It is uncertain whether whether the patent was granted before or after the Pfizer discovery. Phase I clinical trials began in 1995. And after two years of testing, phase II clinical studies began. During this phase, 1997 marked the year that Icos conducted its first study in patients with erectile dysfunction. This phase lasted for two year up to the final third phase.

In 1998, Icos and Eli Lilly and Co. joined forces to commercialize the drug for the treatment of sexual dysfunction. Two years later the new company filed a new drug application with the U.S. Food and Drug Administration for IC351 and  renamed the drug Cialis.

On May 2002 Lilly and Icos reported to the American Urological Association that Phase III test results for Cialis concluded that Cialis remained in the system and kept working for up to 36 hours. These findings were presented at the 97th Annual Meeting of the American Urological Association in Orlando, Florida.

That same year  on November 2002, Cialis was approved in Europe. One year later Lilly and Icos finally won U.S. FDA approval for Cialis on November 21, 2003.