Posted by comftnumb on December 21, 2002, at 23:47:34
Most currently popular antidepressants will be off patent by 2010. When the patents run out, pharmaceutical companies will lose hundreds of millions of dollars to generic versions of the drugs. These companies must look for new drugs to patent in order to remain profitable. Additionally, these new drugs must be more effective or have fewer side effects than the older ones so that people will use them.
The major antidepressants generally have more than one patent recognized by the FDA. These include patents on the drug itself, the uses of the drug for depression, anxiety, or other disorders, and the methods of making the drug through chemical processes. Usually these patents have different expiration dates, but it is often the earliest expiring patent that actually protects the drug from generics. A drug is said to go “off patent” when it is no longer protected from generic versions being made to compete with it.
7 Major Antidepressants:
Prozac is made by Eli Lilly, and is off patent. Many generic forms of the drug now exist. Prozac Weekly is a once-a-week 90mg pill of Prozac. Eli Lilly has the exclusive right to manufacture this “new dosage form” till 2004. Eli Lilly also has a new SSNRI called Cymbalta. Cymbalta is FDA approvable as of September 2002. This means that Lilly first has to clear up FDA identified manufacturing and labeling problems at eight of its factories before it can start selling Cymbalta. These factories should be ready for re-inspection in early 2003.
Zoloft is made by Pfizer, and goes off patent in 2006. Currently Pfizer is in Phase 2 clinical trials of a next-generation antidepressant, identified as CP-122721. The drug belongs to a new class of drugs known as substance P antagonists. According to Pfizer, CP-122721 offers strong efficacy with fewer of the side effects associated with today’s antidepressants.
Paxil is made by GlaxoSmithKline (GSK), and goes off patent in 2007. GSK has two new antidepressants in Phase 2 clinical trials. Vilazodone is an SSRI scheduled for FDA submission in 2004. GW597599 is a substance P antagonist. GSK also has a novel anti-anxiety/antidepressant drug known as SB723620 in Phase 1 clinical trials. This drug is a CRF antagonist.
Wellbutrin SR is also made by GSK, and they currently hold patents extending to 2013. Exactly what those patents protect, however, is unclear because regular Wellbutrin is off patent. Four companies have filed for FDA approval for their versions of extended-release Wellbutrin, claiming GSK’s patents are invalid. GSK has sued all four companies for patent infringement. The cases are currently being held in courts across the US.
Effexor is made by Wyeth (formerly known as American Home Products) and goes off patent in 2007. Effexor XR is patented until 2017, but whether this second patent will hold up after 2007 remains uncertain. Wyeth currently has no new antidepressants in development that have reached Phase 2. (they will not disclose Phase 1 drugs).
Celexa is made by Forest Laboratories. Forest Laboratories has exclusivity to manufacture the “chemical entity” until mid-2003. Forest Laboratories has a NMDA antagonist is Phase II clinical trials. NMDA antagonists hold promise in treating diseases ranging from depression to alzheimer’s to epilepsy. It remains unclear what Forest Labs intends to treat with its own NMDA antagonist.
Lexapro is also made by Forest Laboratories, and goes off patent in 2009. Lexapro is an isomer of Celexa. 10mg of Lexapro has been shown to be as effective as 40mg of Celexa. Whether there are other advantages is unknown.
Other companies and their drugs:
Bristol-Myers Squibb, maker of Serzone, have a CRF antagonist in early clinical development.
Roche Pharmaceuticals, maker of Valium and Klonopin, have several antidepressants in Phase the works but will not disclose
Novartis, maker of Clozaril, has a substance P antagonist in Phase II clinical trials
poster:comftnumb
thread:132839
URL: http://www.dr-bob.org/babble/20021217/msgs/132839.html