Expert blinding not determinative in ADDERALL XR prohibition application

On April 7, 2016., Justice Locke released his Judgment and Reasons in a prohibition application involving Shire, Apotex and the latter’s proposed mixed amphetamine capsules. The patent at issue, Canadian Patent No. 2,348,090, is generally directed to a dosage form with specific pharmacokinetic properties. Claim 22 of the 090 Patent provides:

22. An oral pharmaceutical composition for delivery of one or more amphetamine base salts comprising an immediate release dosage form containing a first dosage amount of said one or more salts effective to treat Attention Deficit Hyperactivity Disorder (ADHD) in a human patient, and a second dosage form containing a second dosage amount of said one or more salts effective to treat ADHD in a human patient which has a release onset lag time sufficient that the plasma concentration/time curve of said composition has substantially the same shape as that of Figure 7, adjusted proportionally for said first and second dosage amounts.

Expert Witness Blinding

Apotex citing the decisions in Apotex rasagiline, Apotex esomeprazole, Apotex ciclesonide, and Apotex gatifloxacin argued that their experts should be preferred over that of Shire because the former provided their evidence without having seen Apotex’s NOA, were never told of Apotex’ position and construed the 090 Patent without any information about the Apotex’s proposed product. Shire, on the other hand, citing Apotex tadalfil argued that the Court’s focus should be on the substance and of the expert’s evidence and not what information was available to them as they prepared their evidence.

Justice Locke agreed with both parties to some extent but held that the blinding of its experts in this case was not determinative. While the evidence of experts unaware of the features of the allegedly infringing product may be helpful in some circumstances, it has not risen to the level of a legal principle that must be applied in all cases.


Justice Locke’s decision largely turned on the proper construction of the asserted claims. Justice Locke preferred Apotex’s evidence for some claim terms and Shire’s evidence for others. One particularly challenging claim limitation was a plasma concentration/time curve which “is substantially the same as that of Figure 7”, since Figure 7 is in the from of a curve, not words.  The  issue between the parties was whether this similarity should be determined quantitatively by an objective, statistical method as suggested by Shire, or a by  subjective, qualitative graphical criteria as suggested by Apotex. While acknowledging that that objective criteria in construing a patent claim is generally preferable, Justice Locke held, in the context of the 090, that substantial similarity should be based on the following five key characteristics of Figure 7 (shown on the left):

Figure 7

[130]       Based on the hints from the 090 Patent (similarities to Figure 1 and differences from Figure 8), I see five key characteristics in Figure 7:

a)  A first ascent (of about 3 hours);

b)  A shoulder without descent (following the first ascent);

c)  A second ascent (after the shoulder);

d)  A sharp peak at about 7 hours (following the second ascent); and

e)  A steady descent (after the peak).


Justice Locke, based on his construction of various claim elements, concluded that Apotex’s proposed capsules did not contain one or more essential elements from each of the asserted claims, such that Shire had failed to demonstrate that Apotex’s allegations of non-infringement were not justified. Having so found, Justice Locke held this he did not have to consider Apotex’s allegation of invalidity or that the claims need not be addressed under the Regulations.

A copy of justice Locke’s Judgment and Reasons may be found here.