Updated: Nov 10
Endo Pharmaceuticals Inc., et al.
Teva Pharmaceuticals USA, Inc., et al.
2017-1240, 2017-1455, 2017-1887
Decided: March 28, 2019
In addition to removing waste products from the blood, kidneys also filter
out drugs and their metabolites. When kidney function is impaired, the rate
at which both waste products and drugs are filtered is decreased; for patients
who take medications, this makes it difficult to determine proper dosage.
Endo pharmaceuticals, manufacturer of the opiate oxymorphone, recognized
that patients with impaired kidney function could be treated effectively—and
without a dangerous buildup of the drug in their bloodstreams—by adjusting
dosage based on the severity of the patient's kidney impairment: the greater
the impairment, the lower the dosage.
Endo’s US Patent No. 8,808,737 covers a method for treating pain in renally
impaired patients that includes the steps of providing a specified oral dose of
oxymorphone; measuring the patient's creatinine clearance rate (“CCR,”
which is correlated with a patient's level of kidney function); placing the
patient into one of four categories of kidney function; and—based on the
patient's measured CCR—choosing a lower dose of the drug so that the 12-
hour average level (the “area under the curve,” or “AUC”) of the drug in the
patient's blood is within a specified range.
Endo sued Teva, Barr, and Actavis in Delaware for infringing the ‘737
patent. The defendant responded with a motion to dismiss, arguing that the
claims are patent-ineligible under §101 because they are directed to the
natural law that the bioavailability of oxymorphone (that is, its level in the
blood) is increased in patients with renal impairment.
The District Court agreed with the defendants, finding under step one of the
Supreme Court’s Alice/Mayo patent eligibility test that the claim is directed
to a natural law; and finding under step two that the claim does not add
enough to the underlying natural law to become a patent-eligible application
of that law.
In reversing the lower court, the Federal Circuit said the District Judge was
wrong to have found the claim ineligible simply because it includes an underlying ineligible concept. The Supreme Court has cautioned that "all
inventions at some level embody, use, reflect, rest upon, or apply laws of
nature, natural phenomena or abstract ideas;" therefore, the proper question
under step one of the Alice/Mayo test is whether the claim is "directed to" a
natural law or abstract idea—not whether it is possible to identify one
underlying the claim.
Here, the panel said that the claim at issue recognizes a natural law—the
relationship between the bioavailability of oxymorphone and the degree of a
patient's renal impairment—but it does not claim that patent-ineligible
relationship. Rather, it claims “a method of treatment including specific
steps to adjust or lower the oxymorphone dose for patients with renal
impairment," which is a specific application of that relationship. The claim
is therefore not "directed to" a natural law, and is patent-eligible.