The Delhi High Court in Biotyx Medical (Shenzhen) Co. Ltd. vs Assistant Controller of Patents and Designs [C.A.(COMM.IPD-PAT) 47/2024], once again dug into a refusal order of the Patent Office and found that the impugned order was based on impermissible hindsight analysis while assessing inventive step. The Court further found that material submissions of the appellant had not been considered and that the reasoning in the impugned order did not support the conclusion of obviousness.
Appellant’s Case
The appellant’s patent application for “Absorbable Stent” was rejected by the Patent Office under Section 15 of the Patents Act, 1970, for lack of inventive step under Section 2(1)(ja) in light of prior arts D1 (US 9427344 B2) and D2 (US 2015/265438 A1). During prosecution of the application, the appellant introduced a limitation in the characterising portion of the claim, reciting the section length of the supporting strut in the range of 0.4–9 mm, to overcome objections relating to novelty and lack of inventive step.
The appellant submitted that in the field of implantable devices, particularly stents, there is a need to limit the prolonged corrosion and absorption cycle of the metal substrate while, at the same time, enhancing the radial strength of the stent to meet clinical applications. The corrosion and absorption cycle can be reduced by reducing the thickness of the metal substrate or by using a metal which has a high corrosion rate, but this would negatively affect the mechanical properties of the stent. The appellant submitted that a metal substrate of higher thickness or a material having a low corrosion rate would have desirable mechanical strength, but it would not corrode in a timely manner after clinical requirements are met.
The appellant asserted that, in the present invention, the absorbable matrix includes multiple turns of wave-shaped rings connected by connection units and arrayed axially. Each wave-shaped ring includes multiple circumferentially arrayed waves and includes a peak, a valley and a supporting strut connecting the peak with the valley. The appellant submitted that the present invention achieves a desirable balance between corrosion cycle and mechanical strength by providing a matrix with smaller matrix volume per unit vascular area and improved radial supporting strength, along with greater section length for the supporting strut and an open-loop design favourable for better side branch capacity.
On Comparison of D1 with the Claimed Invention
The appellant submitted that the objective of D1 is to provide a lockable and expandable bioabsorbable scaffold having low immunogenicity, manufactured from a crystallised polymer blend. Therefore, according to the appellant, the matrix of the stent of D1 would not be able to provide a balance between corrosion cycle and mechanical strength, let alone arrive at a matrix volume per unit vascular area in the range of 4–40 μm and section length of the supporting struts in the range of 0.4–9 mm.
The appellant argued that superior radial support strength, binding performance and side branch passing performance would not be realised based on the teachings of D1. The appellant further submitted that the subject invention achieves a desirable balance between corrosion cycle and mechanical strength by providing a matrix having a smaller matrix volume per unit vascular area in the range of 4–40 μm, improved radial supporting strength, greater section length for the supporting strut and an open-loop design favourable for better side branch capacity.
On Inventive Step
The appellant contended that the respondent Controller had erroneously refused the application on the ground of lack of inventive step by relying on prior arts D1 and D2. The appellant argued that there was no teaching or hint in D1 of any relationship between matrix volume per unit vascular area and section length of supporting struts, which could form a basis for balancing the requirements of a shorter corrosion cycle and enhanced mechanical properties to meet clinical requirements.
According to the appellant, a person skilled in the art, based on the teachings of D1, would not find any actionable teaching or motivation to arrive at the characteristic features claimed in the invention.
The appellant further submitted that D2 was identified as the closest prior art in view of the similarity of its matrix. However, mere similarity in appearance was not sufficient for a person skilled in the art to arrive at the present invention. The scaffold of D2 was made from polymer and not metal, and therefore, the corrosion and mechanical properties of such polymeric materials would be different and not comparable to those of the present invention. It was also submitted that D2 had no teaching on any relationship between matrix volume per unit vascular area and section length of supporting struts, which could balance the requirement of a shorter corrosion cycle with enhanced mechanical properties.
The appellant also argued that D2 disclosed a frustum-shaped scaffold with varying mechanical properties over its length, such as varying stiffness, porosity and elastic modulus. In contrast, the scaffold of the stent of the present invention was not shaped like a frustum and did not have varying mechanical properties over its length. The appellant submitted that the respondent’s reasoning was based on hindsight analysis, as it relied on information revealed by the present invention to hypothesise that if the frustum-shaped stent of D2 were cylindrical, it would necessarily have the same properties as the claimed invention.
Respondent’s Reply
The respondent Controller defended the impugned order and submitted that it was a well-reasoned and speaking order. It was submitted that the claimed invention lacked inventive step as the cited prior arts D1 and D2 disclosed similar stent devices. D1 disclosed a tube or cylindrical-shaped bioabsorbable stent made of polymer. D2 disclosed a stent device comprising a frustum scaffold made from polymer, with a network of rings interconnected by links.
The respondent submitted that D2 was correctly identified as the closest prior art based on the structural similarity of the matrix design. It was argued that both D1 and D2 were linked by a common field of absorbable vascular stents and addressed the same technical problem. According to the respondent, a person skilled in the art would naturally look to both D1 and D2 when designing an improved absorbable stent, and there was no hindsight analysis or mosaicking.
The respondent further submitted that matrix volume per unit vascular area and strut lengths are general design parameters in vascular stent technology and are well established in the art. It was contended that D2 disclosed the same matrix structure as the claimed invention, while D1 disclosed a cylindrical biodegradable vascular stent. Therefore, according to the respondent, there was enough motivation for a person skilled in the art to combine the teachings of D1 and D2 to arrive at the claimed invention.
Court’s Analysis and Findings
On the Subject Matter
The Court noted that to overcome the objections in the First Examination Report relating to novelty and lack of inventive step, the appellant had introduced a limitation in the characterising portion of the claim, reciting the section length of the supporting strut in the range of 0.4–9 mm. By the impugned order, the respondent refused the application on the ground of lack of an inventive step owing to the prior arts D1 and D2.
The Court observed that the present invention sought to achieve a desirable balance between corrosion cycle and mechanical strength by providing a matrix having a smaller matrix volume per unit vascular area in the range of 4-40 μm and improved radial supporting strength, along with greater section length for the supporting strut and an open-loop design favourable for better side branch capacity. When the section length of the supporting struts is in the range of 0.4–9 mm, superior radial support strength, binding performance and side branch passing performance are realised.
On D1
The Court noted that the appellant had specifically brought forth that the objective of D1 was to provide a lockable and expandable bioabsorbable scaffold having low immunogenicity, manufactured from a crystallised polymer blend. The appellant had also submitted that the matrix of the stent of D1 would not be able to provide a balance between corrosion cycle and mechanical strength, nor arrive at the claimed matrix volume per unit vascular area and section length of supporting struts.
The Court found that these submissions on D1 were taken note of by the Controller, but were not dealt with in the “Reasons for Decision”. Instead, the Controller proceeded to deal with submissions relating to D2. The Court held that this was a glaring error and a violation of the principles of natural justice.
On D2
The Court noted that the appellant had brought forth that D2, identified as the closest prior art in view of its matrix, was not sufficient for a person skilled in the art to arrive at the claimed invention merely because of similarity. Firstly, the scaffold of D2 was made of polymer and not metal, and, therefore, the corrosion and mechanical properties of polymeric material would be different. Secondly, D2 had no teaching on the relationship between matrix volume per unit vascular area and section length, which could balance the requirement of a shorter corrosion cycle and enhanced mechanical properties to meet clinical requirements.
The Court observed that the respondent had relied on paragraph [0204] of D2, which disclosed that medical devices may include bio-erodible metals or metal alloys. However, the respondent failed to appreciate that the filed Claim 1 and granted Claim 1 of D2 had an essential limitation that the frustum scaffold of D2 was made from a polymer. The Court noted that D2 clearly teaches using polymeric material for the scaffold and nowhere elucidates that the scaffold is made of metal alone or in combination with polymer.
The Court found that this point had not been dealt with in the impugned order, although it would have had a material bearing on the final decision.
On Lack of Proper Inventive Step Analysis
The Court relied on Agriboard International LLC vs Deputy Controller of Patents and Designs [2022 SCC OnLine Del 940], wherein the Delhi High Court had referred to the Supreme Court’s ruling in Manohar vs State of Maharashtra [(2012) 13 SCC 14] and held that the Controller has to analyse what the existing knowledge is and how the person skilled in the art would move from the existing knowledge to the subject invention. Without such analysis, rejection of a patent application on the ground of lack of inventive step would be contrary to Section 2(1)(ja) itself.
The Court observed that while rejecting an invention for lack of inventive step, the Controller has to consider three elements: the invention disclosed in the prior art, the invention disclosed in the application under consideration, and the manner in which the subject invention would be obvious to a person skilled in the art. Without a discussion on these three elements, arriving at a bare conclusion that the subject invention lacks inventive step would not be permissible, unless the same is absolutely clear.
The Court further observed that the Controller had failed to identify any teaching of D2 which would disclose the claimed relationship between matrix volume per unit vascular area and strut length. The respondent had also failed to bring forth any nexus between the two to render the claimed relationship obvious. The Court found that, while matrix volume per unit vascular area and strut length may be individually known concepts, there was no teaching in the prior art identified by the respondent to show that there existed a relationship between the two concepts so as to balance the requirement of a shorter corrosion cycle and enhanced mechanical properties.
On Hindsight Analysis
The Court found that the impugned order was based on hypothesis and hindsight analysis. The respondent had proceeded on the basis that if D2 disclosed a cylindrical shape instead of a frustum-shaped stent, its properties would be the same as those of the proposed device. The Court observed that there was no reasoning to arrive at this presumptive conclusion. It further held that it was not open to the respondent to refuse the application on a mere hypothesis.
According to the Court, the hypothesis was based on a hindsight approach, which is impermissible in law. The Court noted that a person skilled in the art cannot have divine foresight to identify the properties in the claimed invention from D2 merely on the basis of their shapes.
The Court observed that, on an overall analysis of the impugned order and the documents filed by the appellant, including the response to the First Examination Report and written submissions, the application deserved to be reconsidered. The impugned order was based on hindsight analysis and, more importantly, most of the crucial submissions of the appellant had not been considered. D1, which formed a large part of the impugned order, did not even figure in the reasoning part.
Decision of the Court
The Court quashed and set aside the impugned order dated April 4, 2024 and remanded the matter back to the respondent for considering Indian Patent Application No. 201917030431 afresh in respect of the objection of lack of inventive step. The Court directed the respondent to grant an opportunity of hearing to the appellant and to take into consideration the detailed response to the First Examination Report and the written submissions. The Court also directed that the decision be taken within an outer limit of four months and clarified that it had not expressed any opinion on the merits of the case.
Concluding Remarks
This ruling once again stresses the need for a comprehensive and reasoned analysis of inventive step by the Patent Office. The Court reiterated that inventive step assessment must not be based on hypothesis, hindsight analysis or a selective reading of prior art. The Controller must identify the person skilled in the art, consider the invention disclosed in the prior art, examine the invention disclosed in the subject application and explain the manner in which the subject invention would be obvious to such person.
The judgment also highlights the importance of scientific reasoning in evaluating patent applications. The Court found that the respondent Controller had not considered crucial submissions of the appellant and had not applied a proper methodical approach while assessing inventive step. The ruling, therefore, serves as a reminder that application of mind and recording of a reasoned decision are basic elements of natural justice and must be followed while rejecting patent applications.
Any laxity in adhering to the settled principles governing inventive step analysis may lead the Court to set aside such refusal orders and direct reconsideration of the matter. The Patent Office is therefore expected to ensure that refusal orders are supported by clear reasoning, proper comparison of prior art and a legally recognised assessment of obviousness.
Author: DPS Parmar