Duloxetine was created by Lilly researchers. David Robertson, David Wong, a co-discoverer of fluoxetine, and Joseph Krushinski are listed as inventors on the patent application filed in 1986 and granted in 1990. The first publication on the discovery of the racemic form of duloxetine known as LY227942, was made in 1988. The (+)-enantiomer of LY227942, assigned LY248686, was chosen for further studies, because it inhibited serotonin reuptake in rat synaptosomes two times more potently than (–)-enantiomer. This molecule was subsequently named duloxetine.
Initial trials conducted in patients using regimens of 20 mg/day or less did not convincingly demonstrate its efficacy and the dose was increased to as high as 120 mg in subsequent clinical trials.
In 2001 Lilly filed a New Drug Application (NDA) for duloxetine with the US Food and Drug Administration (FDA). However, in 2003 the FDA "recommended this application as not approvable from the manufacturing and control standpoint" because of "significant cGMP (current Good Manufacturing Practice) violations at the finished product manufacturing facility" of Eli Lilly in Indianapolis. Additionally, "potential liver toxicity" and QTc interval prolongation appeared as a concern. The FDA experts concluded that "Duloxetine can cause hepatotoxicity in the form of transaminase elevations. It may also be a factor in causing more severe liver injury, but there are no cases in the NDA database that clearly demonstrate this. Use of duloxetine in the presence of ethanol may potentiate the deleterious effect of ethanol on the liver." The FDA also recommended "routine blood pressure monitoring" at the new highest recommended dose of 120 mg, "where 24% patients had one or more blood pressure readings of 140/90 vs. 9% of placebo patients."
After the manufacturing issues were resolved, the liver toxicity warning included in the prescribing information, and the follow-up studies showed that duloxetine does not cause QTc interval prolongation, duloxetine was approved by the FDA for depression and diabetic neuropathy in 2004. In 2007 Health Canada approved duloxetine for the treatment of depression and diabetic peripheral neuropathic pain.
Duloxetine was approved for use of stress urinary incontinence (SUI) in the EU in 2004. In 2005, Lilly withdrew the duloxetine application for stress urinary incontinence (SUI) in the U.S., stating that discussions with the FDA indicated "the agency is not prepared at this time to grant approval ... based on the data package submitted." A year later Lilly abandoned the pursuit of this indication in the U.S. market.
The FDA approved duloxetine for the treatment of generalized anxiety disorder in February 2007.
Cymbalta is Eli Lilly's top selling drug. It brought in just shy of $5 billion in 2012 with $4 billion of that in the U.S., but its patent protection terminated January 1, 2014. Lilly received a six month extension beyond June 30, 2013 after testing for the treatment of depression in adolescents, which may produce $1.5 billion in added sales.
1. ^ National Institute for Health and Clinical Excellence.Clinical guideline 40: Urinary incontinence. London, 2006.
2. Jump up^ National Institute for Health and Clinical Excellence.Clinical guideline 96: Neuropathic pain - pharmacological management. London, 2010.
3. Jump up^ Bril V, England J, Franklin GM et al (2011). "Evidence-based guideline: Treatment of painful diabetic neuropathy".Neurology. Online.doi:10.1212/WNL.0b013e3182166ebe.PMID 21482920.