On May 15, 2020, Manson J. of the Federal Court dismissed two actions brought by Biogen under the Patented Medicines (Notice of Compliance) Regulations (PMNOC Regulations) alleging infringement of Patent No. 2,562,277 (277 Patent): Biogen Canada Inc v Taro Pharmaceuticals Inc, 2020 FC 621. Defendants Taro and Pharmascience denied infringement and alleged invalidity on the grounds of anticipation, obviousness and lack of patentable subject matter. This decision and reasons related to the validity of the 277 Patent, and Taro’s alleged infringement. The infringement portion of the Pharmascience action was to take place at a later date.
The 277 Patent pertains to uses of fampridine sustained release (SR) formulations. It is listed on the Patent Register with respect to FAMPYRA, a potassium channel blocker indicated for the symptomatic improvement of walking in adult patients with multiple sclerosis (MS). The asserted claims, as construed, relate to the use of a fampridine SR composition for improving walking in a statistically significant way in a subject with MS in need thereof (i.e. who experiences some form of walking disability) for a period of at least two weeks at a unit dose of 10 mg twice a day. The 277 Patent includes both German-style (use of drug X for treatment of Y) and Swiss-style (use of drug X in the manufacture of a medicament for treatment of Y) use claims.
At issue was whether a registration statement (Acorda S-1) submitted to the U.S. Securities and Exchange Commission anticipated certain claims of the 277 Patent. Acorda S-1 disclosed results from a phase 2 clinical trial (MS-F201) focused on safety and tolerability of fampridine SR administered twice daily over eight weeks of treatment. Acorda S-1 disclosed that doses up to 25 mg twice a day were well tolerated, were associated with statistically significant improvements in walking speed and that most of the improvement was apparent at doses from 10 to 25 mg twice a day. Acorda S-1 also indicated that based on these results, a further phase 2 study (MS-F202) was planned (described as a clinical trial to compare doses of 10, 15 and 20 mg twice daily, and to assess their relative safety and efficacy over a 12-week treatment period, with a primary endpoint of improvement in average walking speed), but no results from that study were disclosed.
Acorda S-1 was found to anticipate claims relating to the use of 10 mg twice daily of fampridine SR for improving walking or increasing walking speed in a subject with MS in need thereof for a period of at least two weeks. The disclosure of the MS-F201 results taught that any of the 10 to 25 mg twice daily doses may be statistically significant. Despite the lack of results from the MS-F202 study, Manson J. held that performing the study protocol would necessarily result in infringement, satisfying the disclosure requirement. He acknowledged the study would fail if the skilled person followed the MS-F202 protocol precisely, however, Manson J. found the enablement requirement was still met. The skilled person, using their common general knowledge, would be able to routinely identify a subgroup of subjects who experienced a statistically significant increase in walking speed when taking 10 mg fampridine SR twice daily.
All of the asserted claims were held to include the inventive concept that 10 mg twice daily of fampridine SR improves walking or increases walking speed in MS patients in need thereof in a statistically significant way. Certain dependent claims include the added feature of pharmacokinetic parameters, namely average plasma concentration at steady state (CavSS) or time to maximum plasma concentration (Tmax) ranges.
Justice Manson found all of the asserted claims invalid for obviousness. He acknowledged that the prior art did not disclose that fixed doses of 10 mg twice daily of fampridine SR taken “for a time period of at least two weeks” would improve walking or increase walking speed in MS subjects with walking disability in a statistically significant way. However, Manson J. held that the skilled person would have understood that 10 mg twice daily dosing of fampridine SR was therapeutically effective to improve walking and increase walking speed for at least some patients with MS, and would have routinely verified this understanding by studying fixed doses of 10 mg twice daily fampridine SR. Dependent claims including the features that were pharmacokinetic parameters were also held not to be inventive on the basis that these were inherent properties of the formulation when administered at the claimed doses.
Methods of Medical Treatment
The Defendants argued that the asserted claims are invalid because they prevent or restrict physicians from applying their skill and judgment. Justice Manson agreed that the 277 Patent claims the use of a known compound for an established purpose using a known treatment methodology. However, he disagreed that these facts grounded a finding of invalidity on the basis of unpatentable subject matter. He also did not accept that there is a general proposition that any patent claim to “how and when” a drug is administered covers unpatentable subject matter. Justice Manson held that all asserted claims are limited to fixed dosages and intervals of administration therefore they are not invalid as methods of medical treatment. Additionally, Manson J. held the Swiss-type claims cover the actions of pharmaceutical manufacturers and therefore do not constrain medical professionals’ exercise of skill and judgment.
In sum, none of the asserted claims were found to cover unpatentable methods of medical treatment, however, the Acorda S-1 reference was found to anticipate certain claims and all of the claims of the 277 Patent were found to be invalid for obviousness. Consideration of infringement was therefore unnecessary. However, based on Taro’s product monograph and expert evidence, Manson J. held Biogen established on a balance of probabilities that if the 277 Patent claims were valid, Taro would have infringed if it made, constructed, used, or sold Taro-Fampridine in accordance with its ANDS. Biogen may appeal as of right.
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