Amifampridine – USA

Amifampridine – USA

On July 31, 2021, New Jersey Court denied Defendants’ motion to dismiss pursuant to FRCP 12(b)(6).

 

Plaintiffs (Catalyst pharma / SERB SA) filed infringement suit against Defendants (Jacobus / Pantherx), for later’s product, Ruzurgi® approved by USFDA in May 2019. Asserted patent-in-suit is US 10,793,893, which is related to methods of administering 3,4-Diaminopyridine (“3 ,4-DAP” / amifampridine). Amifampridine is useful in treating
amifampridine-sensitive diseases, such as Lambert-Eaton Myasthenic Syndrome (“LEMS”), a rare and debilitating neuromuscular disorder. Independent claim 1 of the ‘893 patent recites:

 

“A method of treating a human patient diagnosed with a 3,4-diaminopyridine
(3,4-DAP) sensitive disease in need of treatment thereof comprising administering
a dose of about 2.5 mg to about 30 mg of3,4-DAP or a pharmaceutically acceptable
salt thereof to a human patient who is a slow acetylator having an N -acety 1
transferase 2 (NAT2) gene comprising: a C282T mutation on both alleles of the
NA T2 gene; a T341 C mutation on both alleles of the NA T2 gene; or a C282T
mutation on one allele ofthe NAT2 gene and a T341C mutation on the other allele
of the NA T2 gene”.

 

Defendants moved to dismiss Plaintiffs’ Complaints in their entirety for failure to state a claim, asserting two arguments. Defendants first argued that the Complaints should be dismissed because the ‘893 patent is invalid under 35 U.S.C. § 101 for lack of patent-eligible subject matter. Second, Defendants argued that the Complaints should be dismissed because the Complaints allege no plausible claim of induced infringement against them.

 

35 U.S.C. § 101:

Court said that the Supreme Court has set forth a two-step analysis to determine whether a claim is patent-eligible under § 101 in the Mayo and Alice decisions. First, it need to be determined whether the claims at issue are directed to one of those patent ineligible concepts” i.e. laws of nature, natural phenomena, or abstract ideas. Second, the additional elements of the claim are considered both “individually and ‘as an ordered combination’ to determine whether the additional elements ‘transform the nature of the claim’ into a patent-eligible application.” This second step is described as “a search for an inventive concept. Court said that Defendants’ argument with respect to “total daily dose” in claim 6 and dosages in claims 1 through 5 require interpretation.  This portion of the argument indicates the need for claim construction prior to a § 101 analysis. Moreover, Defendants’ argument also suffers from another deficiency. As noted by Plaintiffs, Defendants’ argument raises many underlying factual issues regarding the novelty of the claimed treatment elements and dosages compared to the prior art (an inquiry under 35 U.S.C. § 102). In addition to this, Defendants did not demonstrate that “the only plausible construction” of the claims renders them patent ineligible under § 101.

 

Induced Infringement:

Defendants argued that Plaintiffs failed to plausibly allege induced infringement based on Ruzurgi® label. Court said that Defendants’ arguments underlying each elements of induced infringement are not persuasive because they hinge upon the assertion that the Ruzurgi® labeling does not specifically identify the claimed NAT2 mutations of claim 1 of the ‘893 patent.  In the Complaints, however, Plaintiffs pointed to the “Pharmacogenomics” section of the Ruzurgi® Prescribing Information which, presumably, refers to the claimed mutations indirectly:

 

“Genetic variants in the N-acetyltransferase gene 2 (NAT2) affect the rate and extent of RUZURGI metabolism. In normal healthy volunteers, poor metabolizers, also referred to as ‘slow acetylators’ (i.e., carriers of two reduced function alleles) had higher average plasma amifampridine concentrations ….

 

Thus, the slow acetylator, or poor metabolizer, NAT2 phenotype of the Ruzurgi® labeling arises from two genetic mutations within NAT2 referred to as “reduced function alleles.” The labeling does not explicitly identify these alleles but Defendants failed to show, however, that “two reduced function alleles” refers to mutations different from those claimed within the ‘893 patent. Thus, it is plausible to infer that “two reduced function alleles” refers to the specific NAT2 mutations claimed in the ‘893 patent. On the other hand, Plaintiffs have shown a plausible inference of specific intent to induce infringement from the Ruzurgi® label.

 

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