Synthon v Teva Pharmaceutical: Purity can be inventive

Teva Pharmaceutical is the proprietor of two patents (EP2177528 and EP2361924) relating to the purity of glatiramer acetate (Copaxone), which is a treatment for multiple sclerosis. Both patents relate to the reduction of metal ion impurities and/or bromine in the drug and processes associated with said reduction. Both impurities cause unwanted effects - metal ion impurities cause the drug to turn red on storage and bromine results in brominated side-products. Synthon sought revocation of the UK parts of both patents on the basis that they lacked novelty in particular over prior sales of Copaxone, inventive step, sufficiency and that the claims contained added matter.

Although a few claims were revoked for added matter, both patents were upheld by the judge (Birss J). Synthon argued that it would be obvious to identify an impurity and remove it. However, Birss J noted that Synthon had not established that the skilled person would note the brominated side products or that identifying the cause of the colouration would be straightforward, and hence reducing either the bromine or metal-ion content would not be obvious. Synthon argued that EPO Board of Appeal Decision T990/96 established a legal principle that using pure reagents in a manufacturing process is never patentable. However, Birss J stated that this decision related to low molecular weight products and not polypeptides as in this case, and that the decision recognised the possibility of exceptions to their general rule.

Interestingly, in the meantime, both patents were revoked by the Hague District Court, but Birss J noted that the evidence in these cases was different on key points and he was therefore able to reach a different conclusion.

This case illustrates the significance of second tier patents (such as those relating to formulations, synthetic processes, new medical uses and dosage regimens) to the pharmaceutical industry, and is another example of a patent case in which different outcomes are achieved in parallel litigation of the same patent in different European countries.

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