Friday, January 30, 2015

Molecular weight, SEC and the US Supreme Court

So a dozen people walk up to the bar and start discussing molecular weight distributions and size-exclusion chromatography (SEC). Let's listen in to what some of them had to say:
"MJ:And as the district court found...the presumed meaning of that term "average molecular weight" when you when you're using this technology is peak average molecular weight. And the there are other technologies such as osmometry and light scattering that give rise to a different presumed meaning of what average molecular weight is, because they produce different measurements. But the only kind of peak average that you can read from the chromatogram is peak average molecular weight. And the Federal Circuit went right by the finding that the presumed meaning would be peak average molecular weight and gave essentially treated the three possibilities, peak, number and weight average, as though they were equal."

MA:"...if you use SEC, then peak molecular weight is produced and that you'd need further calculations to do other things."

JK: "You know, is molecular weight usually measured in kilodaltons or something else."
And who are these twelve people? Why the nine US Supreme Court Justices and the three attorney arguing in front of them.

It's plenty surprising that molecular weight distributions and SEC would be argued about in the Supreme Court, and what is even more surprising, is that they never misspoke about the subject (compare this to previous technical discussions such as the crack smoking poodle, or 2 + 2 is somewhere between 3 and 5, right?). So how did this come to be?

Teva Pharmaceuticals makes the drug Copaxone, used to treat multiple sclerosis. The patent claims from Teva all refer to a copolymer made from amino acids having a molecular weight between X and Y. Sandoz thought the patent claims for this drug were too vague (did they refer to peak molecular weight, number average molecular weight or weight-average molecular weight?) and therefore invalid. Sandoz started making their own version of the drug and of course were sued. Teva won in the district court after expert witnesses convinced the jury that the claims were not too vague. Sandoz appealed to the Court of Appeals for the Federal Circuit (CAFC) and won. But that was in part because the CAFC made a de novo review of the patent claims - they ignored what the jury found and reviewed the matter as if the jury had never decided the issue at all. Appeals courts generally do NOT function like that, but the CAFC does it very frequently. And so Teva appealed to the Supreme Court, arguing that the de novo review should not have happened.

The Supreme Court agreed. No more de novo reviews for the CAFC. The case has now been returned to them to be retried, but without the option of a de novo review. While Sandoz may still prevail, the odds have suddenly gotten a lot tougher. This was a big win for Teva, even though the fight is still not over. It's just that the rules have been changed mid-game in their favor.

This was all argued back in October, and since it appeared that it would be mostly about a legal issue (de novo reviews), I never bothered to follow it. Who knew that it would over its course get into a discussion about molecular weight measurements? Maybe I can get to see them argue of glass transition temperatures someday. Now that would be worth making the trip to DC just to watch.

Previous Years

January 30, 2014 - Does "Literally" Really Mean What You Think It Does?

January 30, 2013 - Clamshell Packaging Takes a Knock

January 30, 2012 - 3-D Printing, Medical Organs and Piracy

January 30, 2009 - Boron Boride

January 30, 2009 - Buckytubes for All!!

1 comment:

agiantamongmolecules said...

What the heck is an "average peak molecular weight"? There is only one Mp, and it is not an average. Also, who the heck uses a GPC to characterize something and then reports the Mp? That is just weird. Everyone reports the Mn and Ð, and then you tell us how you calculated the Mn, e.g. against linear PS standards, with MALS. I guess sometime people report the Mw and Ð if they are trying to irritate me, but never the Mp.