Acadia defends Parkinson’s drug patent against obviousness-type double patenting attack
Court rules that patent must be later-filed to be available as OTDP reference | MSN had submitted ANDA for generic version of Parkinson’s treatment Nuplazid.
A US district court has clarified two issues of obviousness-type double patenting (OTDP) as it granted summary judgment to biotech Acadia Pharmaceuticals in its bid to block a generic version of its Parkinson’s drug from MSN Laboratories.
The US District Court for the District of Delaware had heard arguments from Acadia and its rival MSN in a dispute over the compound patent protecting Acadia’s flagship Parkinson’s treatment Nuplazid.
Ruling in Acadia’s favour, the court held that a first-filed, first-issued patent is not subject to a double patenting attack from a later-filed, later-issuing patent. It also found that an amendment constituted filing for the purposes of the 35 U.S.C. § 121 safe harbour statute and that this protected Acadia’s patent.
Interpretation of § 121
Acadia initiated a patent infringement suit after MSN filed an Abbreviated New Drug Application (ANDA) for a generic version of Nuplazid. The dispute was eventually limited to one of five patents originally asserted; US patent number 7,601,740, which can be traced back to US patent application number 10/759,561.
MSN challenged the validity of the ‘740 patent for OTDP based on US patent number 9,566,271, which traces back to US patent application number 11/416,527.
The ‘527 application was initially filed as a continuation of the ‘561 application, but Acadia amended it to be a divisional in 2010. The ’561 application issued as the ‘740 patent in October 2009, with periods of patent term adjustment and patent term extension added. The ‘271 patent issued in February 2017.
The ‘271 patent contains a claim directed to a method of treating hallucinations associated with Parkinson’s disease psychosis with the tartrate salt of pimavanserin, and the ‘740 patent includes a claim directed to tartrate salt of pimavanserin.
Acadia and MSN put forward differing readings of 35 U.S.C. § 121 as to whether the ‘740 patent was anticipated by the ‘271 patent.
This included whether the language in § 121, which requires the divisional patent to be filed “before the issuance of the patent on the other application” and “as a result” of a restriction requirement, applied when the challenged patent is the original patent, not the divisional patent.
MSN argued that “the Federal Circuit has held that a later-filed child patent can, and did, invalidate an earlier-filed parent patent under OTDP”.
However, the court was persuaded by Acadia’s interpretation of the statue which said it should be read as granting “paramount” protection to original applications. The “filed before the issuance of the patent” requirement applied exclusively to a challenged divisional patent, not a challenged original application, Acadia said.
The court determined that MSN’s interpretation imported “additional limitations not present in the statutory language”.
Furthermore, the ‘740 patent was found to be protected by the safe harbour provision, after the court held that an amendment constituted filing for the purposes of 35 U.S.C § 121.
“Because a patent must be later-filed to be available as an OTDP reference, the Court finds that the ‘271 patent does not qualify as a proper reference against the ‘740 patent,” the judge said.
MSN’s motion for summary judgment of invalidity of the ‘740 patent was denied, and Acadia’s cross motion for summary judgment and no invalidity was granted.
Acadia was represented by Paul Hastings.
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