Big impact patent expiries in the US include Aricept and Flomax, as well as Lipitor whose basic patent expires this year, but will not face competition until 2011 because of Pfizer’s deal with Ranbaxy, the first to file in the USA.

The list, ranked according to US sales, also includes drugs whose patent actually expires, but where the originator company has managed to get a six-month extension due to paediatric exclusivity.

1. Lipitor (atorvastatin) – Pfizer

2. Flomax (tamsulosin) – Boehringer Ingelheim

3. Cozaar/Hyzaar (losartan/losartan potassium-hydrochlorothiazide) – Merck

4. Aricept (donepezil) – Eisai/Pfizer

5. Levaquin (levofloxin) – Johnson and Johnson (J&J)

6. Arimidex (anastrozole) – AstraZeneca

7. Protonix (pantoprazole) – Wyeth/Nycomed/Pfizer

8. Hycamtin (topotecan) – GlaxoSmithKline

9. Climara (estradiol) – Bayer HealthCare

10. Invirase (saquinavir) – Roche

The US patent for Lipitor (atorvastatin) expired in March 2010, however, a deal with generics giant Ranbaxy will protect it from competition until 2011. American sales for the mega-blockbuster cholesterol drug were US$5.3 billion (Euros 3.8 billion) for 2009.

Flomax (tamulosin) lost US patent protection on 27 October 2009, with paediatric exclusivity expiring on 27 April 2010. Global sales for the enlarged prostate treatment were Euros 1.6 billion for 2009. An abbreviated new drug application (ANDA) from Impax Labs for generic tamulosin was approved by the FDA in March 2010.

The US patent for Cozaar/Hyzaar (losartan/losartan potassium-hydrochlorothiazide) expired on 11 August 2009, however, Merck gained paediatric exclusivity until February 2011. American sales for the hypertension treatments in 2009 were US$1.2 billion (Euros 86 million).

The best-selling Alzheimer’s medicine, Aricept (donepezil), which brought in US$1.4 billion (Euros 1 billion) in US sales in 2009, lost US patent protection in November 2010. Several generics manufacturers have already filed ANDAs and Ranbaxy, as the first to file, has won 180-days exclusivity in the USA.

Levaquin (levofloxin) loses its US patent protection on 20 December 2010, but has paediatric exclusivity until 20 June 2011. Johnson & Johnson had US sales worth US$1.4 billion (Euros 1 billion) in 2009. Several generics manufacturers (including Lupin, Mylan and Teva) have already challenged the validity of the '407 patent covering the antibiotic.

Arimidex (anastrozole) lost US patent protection on 27 December 2009, and for paediatric exclusivity on 27 June 2010. American sales for the breast cancer drug in 2009 were US$640 million (Euros 458 million). Numerous generics manufacturers including Dr Reddy’s, Mylan, Natco, Sandoz and US-based Watson, have submitted abbreviated new drug applications.

The proton pump inhibitor Protonix (pantoprazole) lost its US patent protection in July 2010, but has paediatric exclusivity until January 2011. Sun and Teva launched generic versions of the drug in 2007, but stopped shipping shortly afterwards due to patent infringement lawsuits. Wyeth had US sales of the gastric acid prevention worth US$461 million (Euros 330 million) in 2009.

Hycamtin (topotecan), which is used in ovarian and lung cancer, lost its patent protection in the US on 28 May 2010, along with paediatric exclusivity on 28 November 2010. American sales for the chemotherapy agent in 2009 were US$157 million (Euros 113 million). On 30 November 2010, APP Pharmaceuticals announced that they had received approval for their ANDA for generic topotecan.

The US patent for the hormone replacement therapy Climara (estradiol) expired on 29 June 2010 and Mylan already has a generic version on the market.

The US patent for Invirase (saquinavir) expired on 19 November 2010. The antiretroviral drug is used in HIV therapy and as yet there are no generics with ANDA approval.

Globally, patents covering products with US$100 billion (Euros 72 billion) of sales will expire over the next four years, providing a significant opportunity for generic-drug makers, so the future looks bright for the generics industry.

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