This is a dispute between Arrow Generics Limited (“Arrow”) and Merck & Co. Inc (“Merck”). The crux of the decision centered around whether Arrow could obtain a declaration from the UK High Court that their own drug for osteoporosis (which was not patented) was obvious at the priority date of a number of Merck’s pending divisional patent applications.


Merck filed a patent application in July 1998 claiming a priority date of July 1997. This was for a drug called alendronate used in the treatment of bone wasting diseases, including osteoporosis. The drug was to be taken in a 70mg dose once a week (as opposed to previous drugs which were taken in a 10mg dose every day). The benefit to patients was that the 70mg dose was more convenient and produced fewer adverse stomach problems.

The patent (“EP ‘292”) was granted in the UK in November 2001. Arrow commenced revocation proceedings in the UK. The patent was held to be invalid due to lack of inventive step and lack of novelty. The European Patent was also found to be invalid on the same grounds at the European Patent office.

Arrow started to sell alendronate in both the UK and other jurisdictions within Europe, believing that they were commercially safe to do so on the basis that EP ‘292 had been revoked.

However, Merck had filed four divisional patent applications with the same priority date as EP ‘292, covering substantially the same subject matter. The history of the four divisional applications is as follows. They had been stayed pending the outcome of the revocation proceedings. In late 2006 (once the stay had been lifted), the European Patent Office surprisingly confirmed that one of the divisionals, EP 1 175 904, (“EP ‘904”) (which, at that stage, designated the UK), contained patentable subject matter. The European Patent Office justified this decision on the basis of details provided by Merck of a statistically significant effect arising from the administration of 70mg Alendronate tablet once a week. The ‘904 patent was granted in March 2007. For a reason that was not explained by Merck, by the time of grant of the patent the UK was no longer designated and, therefore, this patent was no longer a concern to Arrow in the UK.

However, the similarity of two of the remaining three divisional patent applications (which designated the UK), remained a significant commercial risk to Arrow if granted. Arrow sought commercial certainty from the UK High Court. Mr Justice Kitchin stated in the judgement that “business needs to know where it stands. I believe this Court should assist in providing that certainty where it properly can.”

In order to try and obtain this commercial certainty, Arrow sought a declaration that its own product for alendronate was obvious over the prior art in the field at the priority date of the remaining divisional patent applications, being July 1997.


Arrow’s position was that at July 1997 it was obvious to the skilled person to use alendronate in the manufacture of a 70mg tablet to be taken weekly for treating osteoporosis. It further argued that Arrow’s product contained all those features (and should therefore be held obvious). If Arrow were successful in their application it meant that if Merck’s patent applications were granted, Arrow’s products would be safe from an infringement attack. 

Mr Justice Kitchin awarded the declaration sought by Arrow. He made clear that the Court should assist in providing commercial certainty in patent matters where it can. By providing such a declaration, Arrow could continue trading knowing that they would not incur liability to Merck’s patent rights at a future date. Secondly, the declaration granted was narrower than the original declaration sought by Arrow. The initial declaration sought was that the pending divisional patent applications be held invalid for obviousness over the prior art. The Court ruled that the initial declaration sought could not be granted as it would anticipate the examination phase of the European Patent Office (and the UK High Court did not have jurisdiction to do this). However, because the declaration had been narrowed by Arrow, through identifying certain features of Arrow’s product and the relevant prior art which would render it obvious, there were definite issues which the Court could determine and, as a result, could award such a declaration.


This was clearly an unusual declaration being sought by Arrow. It seems that Mr Justice Kitchin felt that public policy dictated that there should be some form of commercial certainty for Arrow going forward. It may have been a significant issue in the decision that the parent patent (EP ‘292) had been found invalid both within the UK and at the European Patent Office before the divisional applications became a live issue again.