Pfizer will have breathed a sigh of relief yesterday after a US court backed the validity of the main patent covering the world's best selling drug, the cholesterol-lowerer Lipitor, but it was a mixed blessing after a second patent was ruled invalid on technical grounds. Indian generics firm Ranbaxy - the challenger in this case - now says it is assessing its options, but could now launch a copycat rival to the $11 billion dollar a year drug in 2010 rather than 2011.

The main patent covering Lipitor expires in March 2010 but Pfizer's armoury surrounding the calcium salt of the active ingredient atorvastatin has now evaporated; prior to this ruling it was not due to expire until June 2011. Pfizer said it was very disappointed by the decision, noting that the court “turned on a technical defect in the patent.” Such defects, it added can be corrected via the US Patent and Trademark Office “and Pfizer intends to pursue that option.” It may also seek an appeal - as might Ranbaxy - by the full US Court of Appeals.

Lipitor sales in the USA alone are estimated to be in the region of $8.5 billion this year (IMS-MAT: March 2006), clearly a huge opportunity for any generics manufacturer. In a statement, Ranbaxy said it “now has the opportunity to bring the launch date forward to March 2010 from June 2011 with 180-day exclusivity in the US market.” It also said it is considering its options on the 2010 patent.

The decision weighs heavily on the future success of Pfizer's two-pronged approach to improving lipid profiles - its combination of Lipitor and torcetrapib - which is designed to both lower the 'bad' LDL cholesterol and raise levels of the 'good' HDL cholesterol.

Meanwhile, Pfizer UK has today launched the inhaled insulin therapy Exubera in its domestic market. Exubera, which cost-effectiveness body the National Institute for Health and Clinical Excellence ruled should only be used for patients proven to have a phobia of needles, is indicated for the treatment of both type 1 and type 2 diabetes.

Olivier Brandicourt, Managing Director of Pfizer Ltd said: “Exubera offers patients a new choice in the treatment of their condition and meets the needs of clinicians in providing optimal care for their patients. Pfizer is launching inhaled insulin for patients with diabetes in the UK following significant support from doctors, patients and their advocates. There are currently some two million people in the UK diagnosed with diabetes and around a million more thought to be undiagnosed. The costs to the NHS of treating diabetes and its complications,currently run at £158 per second.”