Previously I did not comment on the Amphastar's assertion that the 466 patent is invalid because it is an obvious combination of Linhardt et al., United States Patent No. 4,847,338 (’338 patent) and Sasisekharan ’642. However I have subsequently looked at both of the patents referenced in Amphastar's assertion of obviousness.
1) Ram Sasisekharan's patent US7585642 - General method to characterizing/evaluating polysaccharides including looking at purity and activity. The key thing to know about this patent is that it is general - run this kind of test and then look for these kinds of peaks. But it is not specific to enoxoparin - instead it is intentionally very broad, with one enabling claim each for different type of polysaccharide (including 1 each for LMWH and one for heparin). Accordingly in the claims there are NO values given for each of the potential peaks.
2) Linhardt et al., United States Patent No. 4,847,338 - Linhardt's patent is a patent about creating LMWHs with low anti-coag properties and high anti-complement activity. More specifically it is about making a mixture of tetrasaccharides, hexasaccharides, and octasaccharides for the purpose of low anti-coag and high anti-complement. But again, no specifics whatsoever are given and no numerical guidance is given and nothing specific to enoxoparin.
3) Momenta's patent '466 - This patent is, indeed, fairly similar to the Sasisekharan patent. However it is much more specific: a) It has specificity to enox, including numbers that should be met before producing product, b) unlike Sas it does not describe the entire mixture equally. Instead it focuses on a broad overall characterization (ratios of overall hexa vs tetra vs octa ...) and then micro-focuses on tetrasaccharides as a proxy for the overall status of the mixture. In contrast, if you just followed Sis you'd have to look at all the peaks of all the different components (i.e. tetra, hexa, ...). And, of course, Sis gives no guidance on what the values would need to be to make an acceptable enox product.
All told I'd say it is far from obvious from Sis and Linhardt patents that:
a) the particular numerical values given in the 466 patent are what make for an acceptable enox.
b) that you DO NOT have to look in detail at every single subcomponent of the mixture to know that it is a good enox. You need only look broadly without detail and then in detail at only the tetrasaccharide components. In other words it looks like quite a stretch to say this patent is an obvious combination of Sis and Linhardts patents.
PS Pure speculation on my part - but one possible way to get around this patent might be to use a different subclass (or subclasses) as the proxy for enox status. E.g. perhaps using octasaccharides and hexasaccharides as an adequate proxy instead of tetra. But of course it would take substantial time to prove to the FDA that that new proxy was, in fact, adequate.
Market Data 
Markets 
AI
