The Dolcera Blog

Case background    Avandia is the popular drug name marketed by GSK had strong sales of 2.3 billion USD in 2007 till reports of its cardiovascular risks came out in the market place (forcing lots of physicians to change prescriptions to their patients, though the data was proclaimed as inconclusive by FDA).
    Avandia finds strong applications for glycemic control or in others words for diabetes type II treatment. Its active ingredient is a compound called Rosiglitazone, and a variant of this chemical compound was patented by GSK with expiry in 2005  (US5741803).

GSK Indian strategy

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Per change in the Indian patent act in 2005, GSK filed a patent for the same active ingredient as disclosed in US 5002953 as an Indian patent 00295/DELNP/2003 trying to claim the ethanesulfonate salt of the active ingredient. This patent was subsequently rejected by the India Patent office citing no evidence of the complex showing substantially different clinical efficacy than the available pharmaceutical version of Rosiglitazone.

However, it is interesting to note that GSK has not given up. It has at least three more pending application before the IPO for the same compound Rosiglitazone and we will have to see how the IPO deals with that. These applications are:- 
    a) IN3546/DELNP/2004 in which GSK has tried to patent a cyclodextrin complex of rosiglitazone and

    b) IN4030/DELNP/2005 in which GSK has tried to patent the process for manufacture of a rosiglitazone polymorph (the maleic ester form as patented in US7358366)
    c) IN6569/DELNP/2007 in which GSK has tried to patent a novel method of delivering rosiglitazone (enmeshed in nanofibres)

To counter this threat, Cadila and Dr. Reddys have also filed process patents for manufacture of amorphous Rosiglitazone maleate.

Only time will tell, who will win the Rosiglitazone turf war in India.

Source:

FDA Orange book - http://www.accessdata.fda.gov/scripts/cder/ob/docs/patexclnew.cfm?Appl_No=021071&Product_No=002&table1=OB_Rx

Indian Patent office

US Patent Office

Economic times

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Lakshmikant Goenka

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