While commercial success can sometimes be good evidence of inventive ingenuity, patent applicants should be wary of relying solely on such evidence to avoid rejection on the grounds of obviousness, as factors such as marketing may be found to be the actual reason for the success. In this case, the Patent Appeal Board (“PAB”) rejected the film dispensing cassette disclosed in Canadian Patent Application No. 2,726, 926, (“the ‘926 Application”), entitled “Film-Dispensing Cassette and Rimmed Bag for Waste-Disposal Unit” for obviousness and lack of novelty. 
Canadian Patent No. 2,726,926: Film-Dispensing Cassette and Rimmed Bag for Waste-Disposal Unit
The ‘926 Application describes a film dispensing cassette used in waste-disposal units, which are typically used in the disposal of waste such as diapers and animal litter.  The cassette is placed around the top edge of a waste-disposal unit and has a tubular film packed within it. Film is dispensed from the outer edge of the cassette and is fed from the cassette in a continuous tube. A knot can be tied at the free end of the film to create the enclosed base of the bag. As waste is fed into the center of the film cassette, it causes more film to be drawn from the cassette’s outer edge. 
As can be seen in the above figure, the shape of the cassette is a rounded square, or “squircle”. This shape is the focus of the application. The ‘926 Application claims this shape increases the amount of film that can be stored in the cassette without requiring a drastic increase in the lateral dimensions, making it compatible with existing waste-disposal units. 
The issues to be decided by the PAB include whether the claims lacked novelty and whether the claims would have been obvious.
Novelty: Five Claims Anticipated By Prior Art
In order to approach the test of novelty, the PAB first defined the person skilled in the art as “a person skilled in the art of waste disposal units, in particular those that use film dispensing cassettes.”  They then proceeded to interpret the claims of the application. The only point of dispute was from a passage in claim 1 stating:
“an outline of the central opening in a transverse plane of the device having variable diametrical dimensions with a first diameter being of greater dimension than a second diameter, the outline having in the transverse plane of the device two of the first diameter of generally equal dimension and two of the second diameter of generally equal dimension, with the first diameter being the maximum diameter of the outline in the transverse plane, and with the second diameter being the minimum diameter of the outline in the transverse plane.” 
The PAB felt that a skilled person would consider a requirement of two maximum and two minimum diameters to be inconsistent with certain embodiments disclosed in the application. For example, a rectangle and oval only have one minimum diameter and a hexagon has three minimum and three maximum diameters.  The applicant argued that claim 1 should be construed to mean ”at least two” maximum diameters and ”at least two” minimum diameters.  The PAB rejected this argument as it did not solve the issue of the rectangle and oval shapes and there was no support in the description for an ”at least two” criterion.  Further, the PAB took issue with the fact that this limitation did not impose any upper limit on the number of maximum and minimum diameters. As the number of diameters becomes sufficiently large, the shape essentially becomes a circle, which is the conventional shape the applicant intended to improve upon.  The PAB concluded that a skilled person would understand claim 1 to be limited to exactly two maximum and two minimum diameters.
The PAB then applied the two-part test that was articulated in Apotex Inc. v. Sanofi Synthelabo Canada Inc. (“Sanofi”) to determine if the claimed invention was anticipated.  The first step is to determine if a single piece of prior art discloses the claimed subject matter and the second step is to determine if such prior disclosure would enable the claimed subject matter to be practiced by a person skilled in the art. 
In their analysis of the first step of the test, the PAB found that claims 1-4 and 12 were disclosed by a piece of prior art.  The applicant contended that this prior art only disclosed a circular opening. However, in the PAB’s view, the skilled person would understand the passage “other shapes such as squares, rectangles, ovals and the like” to mean these shapes are explicitly disclosed as an alternate shape. [48, 51] On proceeding to the second step of the test, it was found that in light of the drawings and description within the prior art, a skilled person would have been able to make a film cassette having the essential features of claims 1-4 and 12 without undue burden.  As both steps of the novelty test were answered in the affirmative, it was concluded that these five claims were anticipated.
Obviousness: No Inventive Ingenuity Found Despite Commercial Success
Upon applying the test for obviousness, also articulated in Sanofi, the discussion once again revolved around the shape of the claimed invention. The applicant contended that in order to arrive at a square-shaped film cassette based on the prior art, a skilled person must perform ‘mental gymnastics’.  The PAB, however, felt that a skilled person would understand from the prior art that a variety of shapes, including a square, were equally viable and that the disclosure was not limited only to a circular embodiment.  Additionally, while the applicant argued that the prior art was limited to a tubular central portion, the PAB believed the skilled person would not take the word tubular to mean only circular or oval cross-sections and that a square cross-section could be considered tubular.
A final argument that was made by the applicant was that the commercial success of the product was indicative of the “uniqueness of the claimed invention, and of the unexpected advantages provided by the recited shape of its central opening.” This argument was rejected. The PAB noted that commercial success may in some cases support inventive ingenuity, but in the case at hand, the sales figures alone did not demonstrate that the commercial success wasn’t due to other factors such as marketing. [23, 70] It was concluded that all claims of the invention were found to lack inventive ingenuity and as such, were obvious.