Document ID: ./input/supremecourt_opinions/opinions/11pdf/10-1150.pdf
Page Number: 9

Cite as:  566 U. S. ____ (2012) 

5 

Opinion of the Court 

ous studies suggested that measurement of 6–MP metabo­
lite  levels  can  be  used  to  predict  clinical  efficacy  and  tol- 
erance  to  azathioprine  or  6–MP”  (citing  Cuffari,  Théorêt, 
Latour,  &  Seidman,  6-Mercaptopurine  Metabolism  in 
Crohn’s  Disease:  Correlation  with  Efficacy  and  Toxicity,
39  Gut  401  (1996))).  But  those  in  the  field  did  not  know 
the  precise  correlations  between  metabolite  levels  and
likely harm or ineffectiveness.  The patent claims at issue 
here  set  forth  processes  embodying  researchers’  findings 
that identified these correlations with some precision.

More  specifically, 

the  patents—U. S.  Patent  No. 
6,355,623  (’623  patent)  and  U. S.  Patent  No.  6,680,302
(’302  patent)—embody  findings  that  concentrations  in  a 
patient’s blood of 6–TG or of 6–MMP metabolite beyond a 
certain level (400 and 7000 picomoles per 8x108 red blood 
cells,  respectively)  indicate  that  the  dosage  is  likely  too 
high  for  the  patient,  while  concentrations  in  the  blood  of 
6–TG  metabolite  lower  than  a  certain  level  (about  230 
picomoles  per  8x108  red  blood  cells)  indicate  that  the
dosage is likely too low to be effective. 

The patent claims seek to embody this research in a set 
of  processes.    Like  the  Federal  Circuit  we  take  as  typical
claim  1  of  the  ’623  Patent,  which  describes  one  of  the 
claimed processes as follows: 

“A  method  of  optimizing  therapeutic  efficacy  for
treatment  of  an  immune-mediated  gastrointestinal 
disorder, comprising:
“(a)  administering  a  drug  providing  6-thioguanine  to 
a subject having said immune-mediated gastrointesti­
nal disorder; and 
“(b)  determining  the  level  of  6-thioguanine  in  said 
subject  having  said  immune-mediated  gastrointesti­
nal disorder, 
“wherein  the  level  of  6-thioguanine  less  than  about 
230 pmol per 8x108 red blood cells indicates a need to