Challenging the Validity of Patents: Stepping in Line with EPO and US Jurisprudence

As a matter of law, patents are granted with a presumption of validity. However, with the public interest considered as an essential basis for the granting of exclusive rights, subject only to procedural fairness, a competent national or regional authority may revoke or invalidate any patent that fails to comply with formal patentability requirements as grounded in law. Remarkably, at the heart of the most successful patent regimes lies a sensible framework that allows any interested third-party to challenge the validity of questionable patents. However, these instruments are not found within the least developed patent regimes. Importantly, given the conceptual reasoning that invalidly granted patents stand to prejudice the overriding public interest, a principle centrally established in the patent system, this article examines the extent to which states can implement legislative instruments on patent opposition to mitigate the potential consequences of granting questionable patents. Therefore, drawing on the jurisprudence containing the substantive law and procedural requirements of patent opposition proceedings within the EPO and USPTO, the author argues that citizens in whose interests patents are granted have the right to participate in the patent system and to check that only inventions that deserve exclusive rights are granted patents. The conclusion is that, if WTO members without patent opposition mechanisms were to explore and strengthen their regimes, citizens, competitors and other interest groups would be able to detect and invoke key provisions to challenge the granting of invalid patents, while maintaining that the patent system is untainted and free from questionable patent claims.


Introduction
The patent system was designed with the intention of promoting innovation, and the exclusive rights granted to patentees are subject to limitations. 1 Monopoly rights confer on their owners the right to prevent others from carrying out certain acts, such as using, selling or importing patented products or processes without the patent owner's consent. 2 The patent landscape is mainly governed by the World Trade Organisation's (WTO) 3 Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS Agreement), 4 which provides adequate standards concerning the availability, scope and use and appropriate means for the enforcement of patent rights. 5 As a matter of empirical logic, just as the patent system has its positives, there also exist social cost implications. 6 The social cost aspect of the patent system is related to the notion of static efficiency losses resulting from monopoly and other market distortions, which can undermine the public interest. 7 Importantly, Art. 8 establishes principles that underpin the entire TRIPS Agreement, and this provision captures well the need to protect the public interest. 8 However, this is not automatic, and it does not exist in a vacuum. 9 The central thrust is that while patent law provides the legal framework for the patent system, it does not define the scope of public interest in terms of a specific outcome. Keeping in perspective this understanding, several other features should support the patent system so that it works in the way that it is intended to work to promote this. 10 To meet this objective, patent law should lay down some rigorous requirements, both procedural and substantive, for obtaining patents, 11 in satisfaction of the public interest. Those requirements are fundamental to a well-functioning patent system, as they were created to ensure that only those inventions that are worth protecting for the purposes of facilitating innovation and meeting the broad public interest obtain patent protection. 12 Article 29 of TRIPS essentially sets out certain conditions one of which is that the applicant must disclose the invention in a manner that is sufficiently clear and complete. 13 Nevertheless, it may be that a substantive examiner overlooks a piece of prior art and advertently reaches a positive decision regarding the patentability of the claimed invention. 14 In other words, regardless of patent law normally having a general set of legal rules to govern the validity of a patent, 15 even with the most rigorous examination system, the state cannot guarantee that the rights that it grants are valid, as there is always the possibility that a prior art may be unobserved or a specification misunderstood. 16 That is, the increase in demand for patent rights places additional pressures on Patent Offices to examine and grant patent applications, 17 and examiners may make mistakes in judging novelty or inventive step in the light of the state of the art that the patent search revealed. 18 Added to this fact is the argument that some applicants, with a view to obtaining exclusive rights, may submit questionable patent applications. 19 The general meaning of a ''questionable patent'' relates to ''poor quality'' or any patent that has been granted improperly. 20 Where this is the case, it will provide a workable basis for invalidating such patents given its presumed inconsistency with the general statutory requirements. These include novelty, non-obviousness, usefulness, 21 and the requirement of disclosure as grounded in the law against which patent applications are evaluated. 22 Moreover, several grounds are often covered, which commonly include: suppression of information about foreign filing, and anticipation having regard to traditional knowledge. 23 Traditionally, opposition proceedings have been limited to competitors and governments. 24 The government can challenge issued patents and even revoke them. 25 However, such government-led actions are currently rare. 26 Notably, several countries have broadened this to include interested persons, such as civil society organisations. 27 Consequently, where the patent system allows too many questionable patents to prevail, without offering an inexpensive and timely mechanism for invalidation, such a regime will not be fit for purpose, as it ignores the social benefit gained by granting patents, and overlooks the fundamental fact that patents are for the benefit of the public. 28 It is on this foundation that several countries continue to take policy decisions that allow opposition proceedings to restrain the granting of questionable patents and claim a right over the same. 29 The problems associated with the existence of questionable patents, and the need for an effective, inexpensive legislative vehicle to challenge them are not entirely new to the patent system. 30 Importantly, the patent validity challenge is not an accident or a mistake; rather, it is an inherent part of our patent system. 31 No international treaty sets standards on the general framework of patent opposition mechanisms as such.
Importantly, some general procedural requirements prescribed in the TRIPS Agreement, and the Patent Law Treaty (PLT) 32 may also be applicable to opposition procedures. The attitude of these two treaties is, via the international accepted standards, to remind states of the guiding principles of fundamental fairness that must be the hallmark of opposition proceedings rather than to strictly prescribe a constitutive approach to the same. To take an illustration of this, Arts. 32 and 62 of TRIPS and Art. 10(2) of the PLT leave open cases in which signatory states can exercise wider discretion on this subject-matter. 33 Under the framework of TRIPS, the Agreement does not state specifically the grounds upon which members should provide opposition mechanisms. 34 Therefore, members are free to provide, or not to provide, an opposition mechanism in their national laws, 35 except that the most successful patent regimes, such as the European Union (EU), 36 the United States (US), 37 Japan 38 and India, 39 which uphold the notion of public interest protection, allow for some form of opposition mechanism. 28 Graham v. John Deere Co. of Kansas City, 383 U.S. 1, 5-6 (1966). 29 Puasiri (2013) Nevertheless, these instruments of contestation are not common in some countries, 40 or may be highly ineffective in countries where they exist, 41 whereas a conceivable reality is that a high number of questionable patents may be being issued by Patent Offices and, at the same time, many of them are not being invalidated. 42 Importantly, given the conceptual reasoning that invalidly granted patents stand to prejudice the overriding public interest, a principle centrally established in the patent system, this article examines the extent to which states can implement legislative instruments on patent opposition to mitigate the potential consequences of granting questionable patents. Therefore, drawing on the jurisprudence containing the substantive law and procedural requirements of patent opposition proceedings within the EPO and USPTO, the author argues that citizens in whose interests patents are granted have the right to participate in the patent system and to check that only inventions that deserve exclusive rights are granted patents. The conclusion is that, if WTO members without patent opposition mechanisms were to explore and strengthen their regimes, citizens, competitors and other interest groups would be able to detect and invoke key provisions to challenge the granting of invalid patents, while maintaining that the patent system is untainted and free from questionable patent claims.

Deficient Prosecution and the Grant of Questionable Patents
A common normative belief in the patent system is that patents are normally granted to protect genuinely new and inventive products and processes. 43 Notwithstanding this, patents are not awarded automatically but rather, they must be applied for and will only be granted if the examiner in the Patent Office, via the prosecution process, considers that the application meets all of the necessary legal requirements; the key requirements, as already mentioned, are that the invention is novel and not obvious. 44 While some countries, either due to capacity constraints or as a deliberate instrument of government policy, have lax patentability criteria, 45 some have also adopted strict patentability criteria regarding what does and does not deserve a patent, via the prosecution process. 46 The common theme of this stringent system is 40  , parts II.C, II.E. 41 For example, the national legislation of Uganda and Tanzania-Zanzibar provides for pre-and postgrant administrative opposition procedures. See, Secs. 28(7)-(12), 32(5) and (6) of the Uganda Industrial Property Act, (2013); and Secs. 10(7)(a) and 16 of the Zanzibar Industrial Property Act of (2008 based on the notion that the lower the quality of patents, the greater the fraction of rights that have been improperly issued, and the less efficient the patent system is at stimulating innovation and promoting the public interest. 47 However, it is important to keep in mind that even when a Patent Office has strict standards for patentability during patent prosecution, there is no guarantee that they will be adequately applied; put differently, such mechanisms are far from perfect. 48 In a general legal sense, prosecution has a different context in IP law; it is the process of writing and filing a patent application and pursuing protection for the patent application with the Patent Office. 49 Put differently, it is the stage between the filing of a patent application and its final disposition. This involves the entire administrative procedure through which a patent application becomes a patent. However, patent examination is an ex parte proceeding between the Patent Office examiner and the applicant. 50 It does not therefore seem sensible, following this one-sided procedure, to treat every granted patent as though it has always met some higher standards of patentability. 51 Central to this debate is the pervasive and growing concern that the Patent Office grants far too many questionable patents, which, were they to be subjected to a thorough review, would be likely to be found invalid. 52 Patent validity is not just about the correct application of the standard of patentability. More fundamentally, it requires those who administer the patent system to operate with an evidence-based understanding of creativity that drives the patent system's test of non-obviousness. 53 However, this is not always the case. The resulting inadequacies in the Patent Office arguably lead to the application of low threshold of patentability standards. The causes of poor quality examination at the Patent Office are manifold and well documented in the literature. 54 Frequently cited reasons include: inadequate Patent Office resources to thoroughly review each application, biased procedures that favour the patent applicant or skewed incentives that make it easier for an examiner to allow an application rather than reject it. 55 These general insights shift the conventional view in a subtle but, importantly, understandable way, and it becomes clear that the quality of a patent depends on the underlying examination at the Patent Office. 56 The patent rules of practice and administrative regulations are the genesis of the problem, and driving this are evidentiary mechanisms that include presumptions and shifting burdens of proof. 57 Put differently, this problem often flows directly from 47 Lemley and Shapiro (2005)

818
T. Manu key administrative practices and operating procedures, whereby there is a strong presumption that an adequate written description of the claimed invention is present when the application is filed. 58 This presumption obliges the Patent Office examiner to treat as true the patent applicant's assertions, or documentary evidence that is filed regarding certain facts in relation to the asserted usefulness of the invention; unless countervailing evidence can be provided to dismiss the accuracy or reliability of such information then there is no legitimate basis to doubt the credibility of such an application. 59 Under these constricted substantive and procedural environments, a patent applicant enjoys a presumption of patentability. 60 That is, at the time of filing, the application is rebuttably presumed to comply with the utility, novelty, non-obviousness, and disclosure requirements of the patent law. 61 This presumption allocates the burden of proof to the contrary, and it commonly tends to favour the issuance of a patent unless the Patent Office can establish a prima facie case for rejection of the patent application. 62 Thus, the burden of proving unpatentability rests with the Patent Office. 63 Under this conceptual logic, the Patent Office must issue a patent unless it can affirmatively prove that the invention is unpatentable. 64 This presumption is seen by many as preserving the strength of patent applications given that this presumption is not to be overthrown, except by clear and cogent evidence that tilts the presumption. 65 The scales are therefore tipped even further towards issuance if the examiner lacks the time, materials or incentives to conduct a high-quality examination. 66 The bottom line is that anyone who files a patent application for anything starts off in a very good position. 67 Added to the foregoing assumption is the norm that an issued patent is presumed valid, and the courts require a party that challenges a patent to prove its invalidity with clear and convincing evidence to overturn that presumption. 68 Perhaps the most important threshold requirement to invalidate a questionable patent is to establish that the claimed invention does not meet one or more of the 58 63 In re Rijckaert, 9 F.3d 1531, 1532 (Fed. Cir. 1993), finding that an examiner must affirmatively prove unpatentability. 64 In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992), if examination at the initial stage does not produce a prima facie case of unpatentability, then without more the applicant is entitled to the granting of the patent. 65 Miller (2004), p. 689, stating that the Patent Office appears to grant many patents that, when carefully scrutinised, fail to meet basic patentability standards. 66 Long (2002), pp. 667-668, observing that the constraints of time, information, and evidentiary standards create a situation where the Patent Office's evaluation of a patent application may be so poor or hurried as to be near meaningless. Leslie (2006), p. 109. Shapiro (2004), p. 1019. 67 FTC Report (2003), Ch. 5, p. 9, finding that Patent applicants are in a great position because by filing an application they are presumptively entitled to receive the grant. 68 Ibid. p. 8. patentability criteria. 69 Still, the risk that a patent will surely be declared invalid is unpredictable. Even though the patent applicant owes a duty of candor to the Patent Office, 70 no one believes that everything that the applicant knows about the invention ends up before the examiner despite a legal obligation on the patent applicant to disclose information material on patentability. 71 Moreover, that duty does not require an applicant to search for prior art beyond that about which he already knows. We learn immediately that if the examiner does not produce a prima facie case (of obviousness), then the applicant is under no obligation to submit evidence of non-obviousness. 72 Of course, the information deficit inevitably allows questionable patents to be granted. This difficult position is compounded by the fact that while the examiner may be aware of potential abuse, they often cannot lawfully reject an application on the grounds of poor disclosure, except in extreme cases. 73 Several cases in which ''patent trolls'' and clear abuses of the system have occurred over the years, especially in the US, have shown that applicants in bad faith can take advantage of the mild enforcement of the duty of disclosure, and scholars have extensively discussed this problem. 74 Likewise, the US Manual of Patent Examining Procedure states that the USTPO ''does not investigate'' duty of disclosure issues and ''does not … reject'' applications on that basis. 75 Within this notion, even if sound patent policy calls for targeted legislative intervention to sanitise the patent system, then this may not be a fruitful exercise at times. 76 Moreover, the patent examiner's task is particularly challenging if the technological or scientific frontier is moving fast, and if relevant information has not yet been included fully in the written material that he is using to understand the state of the art. 77 Another challenging aspect is the mounting number of patent applications that the Patent Office must examine, which could lead to the granting of questionable patents. 78 Professor Wagner flags this quite clearly as ''the amount of patenting activity has grown rapidly worldwide, the administrative apparatus of the patent system has been strained to its limits'', 79 thereby emphasising the claim that the reason why we have questionable patents is because ''the incentives to file low-quality patents are too high, and the incentives to file high-quality patents are too low''. 80 This is relevant, as hundreds of thousands of applications filed each year end up having no commercial significance. 81 Where the Patent Office's resources to evaluate patent applications seem inadequate, such as an underfunded Patent Office, then there may not be sufficient time to evaluate patent applications fully or to allow efficient and accurate screening of all patent applications. 82 This has contributed to an extensive debate in which experts have mapped out policy reforms to nurture the quality of patents. 83 Scholarly debates have categorised reforms into five broadly defined themes: administrative changes, patent law changes, better patent information to patent applicants and examiners, better incentives to improve patent quality, and more technical advancement for patent examiners. 84 However, as Professor Miller has argued; ''even if the Patent Office were to invest far more in reviewing applications, its review would still suffer from a basic knowledge deficit compared to that which well-informed inventors and their competitors possess''. 85 Importantly, Professor Lemley balances accuracy and operational overheads, and argues persuasively in support of the viewpoint that strengthening the examination process is not cost effective, and society is better off spending its resources on a more searching judicial inquiry into validity in those few cases in which it matters, rather than paying for a more protracted examination of all patents ex ante. 86 This argument rests on the assumption that litigation is likely to lead to the correct decision. However, there can be a serious problem with this assumption. Professor Drahos assumes that while patent litigation is a quality filter, it cannot be relied on in developing countries where there is no tradition of litigation and there are low levels of local patent litigation expertise. Furthermore, in some countries, there are problems relating to the integrity of the judicial system. 87 In the narrative, Professor Lemley states that while maintaining a check on the quality of patents is the most vital consideration for any Patent Office, 88 an opposition system seems to be an efficient way of providing an additional layer for checking any errors and abuse in the patent system to ensure the quality of patents. 89 80 Ibid. p. 2172. 81 Farrell and Shapiro (2008), p. 1361. 82 Id. 3 Challenging the Validity of Patents: Jurisprudence of the EPO and US Patent quality, according to Professor Drahos, is different from the quality of an invention. A Patent Office does not judge the quality of an invention independently of the criteria of patentability. The Patent Office assesses an invention in order to ensure that it meets the prevailing legal standard of inventiveness or non-obviousness. Once a patent examiner decides that the invention satisfies the standard, there is no further inquiry into the quality of the invention. 90 Judgements about the quality of an invention are left to markets or to the inventor's relevant peer group. 91 When it comes to analysing patent quality the starting point is the fact that a patent is a legal product -a personal property right that may be assigned or licensed. This legal product is the outcome of an examination process in which, if the standards of patentability are applied correctly, the applicant will be granted a valid patent. 92 Patent quality then can be defined in terms of the correct application of the standards of patentability by a Patent Office. 93 High quality patents (correctly issued patents) do not necessarily mean high invention quality. 94 For example, the patent law of some countries stipulates that the granting of a patent is no guarantee of its validity. 95 Still, Patent Offices take the view that a quality patent is one that has been correctly granted. 96 This raises the question of how one knows whether a Patent Office is correctly applying the criteria of patentability. One possibility is to use court decisions concerning the validity of granted patents in order to gain some sort of insight into the quality of work of a Patent Office. However, there are some problems with using court decisions to assess the quality of a Patent Office's work. Even in the US, where the patent ligation market is very large, only a small percentage of patents are litigated and a clear majority are settled by the parties prior to judgement. 97 Therefore, several countries provide other kinds of proceedings that test the work of a Patent Office. In this context, most of the successful patent regimes have statutory mechanisms whereby an interested third party can express its opposition against the granting of a patent or against a granted patent. 98 In general, opposition proceedings are conducted before the Patent Office, and not a court per se. 99 An opponent must allege at least one of the grounds for 90 Drahos (2010)  opposition out of those prescribed in the applicable law. 100 Opposition procedures are closely related to the patent granting procedure. An opposition may be requested soon before the granting of a patent (pre-grant opposition) or after the granting of a patent (post-grant opposition). 101 In some countries, an opposition may be filed within a certain time immediately after the publication of the application for a patent and before the examination phase, in which case the procedure resembles, to a certain extent, the so-called third-party observation system. 102 It is possible to combine pre-grant and post-grant opposition systems. 103 The advantage of a pre-grant opposition system is that it precludes questionable patents from being granted at an early stage and may also be beneficial for a patentee, since the patentee and the public can have more trust in the validity of the patent. 104 However, a common drawback of a pre-grant opposition system is that it may cause a substantial delay in the whole process of finalising the granting of a patent, 105 and result in stifling technological progress and causing economic harm. 106 Similarly, the major shortcoming of post-grant opposition systems is that they lead to the wrongful monopoly of a patent holder until the time at which an opposition is filed for the patent. While such laws differ in terms of their substantive construction and the general procedural requirements, their legal logic is similar. The common objective is to provide a simple, quick and inexpensive means to increase patent quality by providing additional input to the process to ensure that undeserving patents are not granted exclusive rights. 107 These mechanisms also provide an alternative to potentially lengthy and costly judicial proceedings, since the current patent system has a de facto reliance on litigation as the primary vehicle for invalidating patents -a reliance that has adverse public consequences. 108 It is worth noting that no international treaty regulates post- 100 In the EPO, where the subject-matter of the European patent is not patentable under Arts. 52-57 because it is not new (Arts. 52(1), 54, 55); does not involve an inventive step (Art. 52(1), 56); is not susceptible to industrial application (Arts. 52(1), 57); is not regarded as an invention under (Art. 52(1)-(3) or is not patentable under Art. 53. Additional grounds are that the European patent does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art (Art. 83) or the subject-matter of the European patent extends beyond the content of the application as filed (Art. 123(2)) or, if the patent was granted on a divisional application or on a new application filed under Art. 61 (new application in respect of the invention by the person adjudged in a final decision to be entitled to the grant of a European patent), beyond the content of the earlier application as filed (see, Art. 76(1)). 101  grant patent opposition mechanisms as such, 109 and there are operative provisions in the current patent regime, specifically dealing with the regulation of opposition procedures, which consider what was set forth on procedural matters in general under TRIPS 110 and within the PLT. 111 This paucity thereby leaves WTO members free to decide on the matter. Under this logic, and consistent with WTO Dispute Settlement Understanding findings, each state creates its own regime, and these laws emphasise the overriding character of national patent policies, which are essentially the result of the legal vacuum created by the international treaty, 112 leaving members free to determine the appropriate method of implementing opposition mechanisms within their own legal system and practice. 113 Both the European and US patent regimes support patent opposition instruments.
Under US patent law, an opposition proceeding is called a re-examination. 114 Originally, there were two types of re-examination procedure in the US and these requests fall into one of two categories: inter partes re-examinations, which allow the requesting party to participate in the proceedings; and ex parte re-examinations, which are conducted substantially exclusively between the patent owner and the United States Patents and Trademarks Office (USPTO). 115 However, the Leahy-Smith America Invents Act introduced post-grant review proceedings into US patent law, by adding a new Chapter 32 to Title 35 of the United States Code. 116 Although prior to this the US patent law permitted a form of post-grant review of issued patents through re-examination proceedings, 117 the re-examination proceedings were limited to issues of patentability relating to prior art patents or printed publications that establish ''a substantial new question of patentability''. 118 The America Invents Act significantly expands these options, by providing a new post-grant review proceeding, which is, in many respects, similar to foreign 109 WIPO, SCP/17/9 (2011), p. 13, para. 37. 110 Article 32 of TRIPS reads: ''An opportunity for judicial review of any decision to revoke or forfeit a patent shall be available''. 111 Article 10 of the Patent Law Treaty, 1 June (2000), 39 I.L.M. 1047. Note that the aim of the Patent Law Treaty (PLT) is to harmonise and streamline formal procedures in respect of national and regional patent applications and patents and, thus, to make such procedures more user friendly. With the significant exception of filing date requirements (Art. 5), the PLT provides the maximum sets of requirements that the office of a contracting party may apply (Art. 2). This means that a contracting party is free to provide for requirements that are more generous from the viewpoint of applicants and owners, but the requirements under the PLT are mandatory in regard to the maximum an office can require from applicants or owners. opposition mechanisms. 119 In other words, the America Invents Act reformed inter partes re-examination proceedings with two different types of administrative postgrant proceedings: post-grant review and inter partes review. 120 Under the new America Invents Act, any third party ''who is not the owner of a patent'' can challenge the validity of an issued patent using either post-grant review, 121 or inter partes review by filing a petition with the USPTO. 122 The primary objective of the inter partes re-examination procedure is to reduce costly patent litigation in US District Courts by providing an expanded means for third parties to challenge the validity of a patent. 123 Nevertheless, post-grant review must be initiated within 9 months of the issuance of a patent, and permits any patentability issue to be raised, which can be based on any evidence, and at least one claim of the patent. 124 That is, the petition for post-grant review must provide evidence that supports the grounds for the challenge to each claim, 125 except that an inter partes review cannot be initiated until the later of 9 months after a patent issue or after post-grant review is complete. Furthermore, inter partes review is limited to the grounds of novelty or non-obviousness, and non-patentable subject-matter. 126 The person challenging the validity of the granted patent does not need to show an interest in it, 127 and requests may be filed any time during the enforceability of a patent after the foregoing period has expired. 128 In this case the burden of proof is on the challenger due to the jurisdictive notion of the ''presumption of validity''. 129 However, while this legal logic follows the US patent law principle, which states that ''patents shall be presumed valid'', 130 what deviates from the US legal scope is the trial procedure created under the American Invents Act. 131 In litigation, under 35 U.S.C. § 282, an issued patent is ''presumed valid''. Accordingly, an invalidity defence in court must be proved by clear and convincing evidence. 132 In contrast, in each of the new post-issuance validity proceedings, there will be no presumption of validity for patents that are reviewed; thus, invalidity need only be established by a preponderance of the evidence. 133 Likewise, the new Trial Practice and Procedure Rules confirm that 'the default evidentiary standard is a preponderance of the evidence', 134 which is a lower threshold than the clear and convincing evidence standard applied to invalidity determinations in litigation.
Under the EU jurisprudence, a notice of opposition may be filed at the European Patent Office. 135 The post-grant opposition in the EU is more of a postcontentious, 136 inter partes, administrative 137 procedure intended to allow any European patent to be centrally opposed. 138 Opposition proceedings are available to the public. 139 More importantly, as per the European Patent Convention (EPC), 140 any person, natural person or legal entity who is not the patent owner can file an opposition to a European patent within 9 months of the publication of details in the European Patent Bulletin. 141 The opposition applies to any European patent in all contracting states in which the said patent has effect. 142 Significantly, an opposition may be filed by a straw man to hide the identity of the party actually interested in having the patent revoked. 143 A straw man is ''a party acting on behalf of another person''. 144 In 1999, the Enlarged Board of Appeal held that the use of a straw man did not render the opposition inadmissible unless ''the involvement of the opponent is to be regarded as circumventing the law by abuse of process''. 145 As provided by Art. 100 of the EPC, the opposition must be based on at least one ground for opposition, 146 accompanied by evidence that supports the grounds for opposition. 147 The following grounds are available for interested parties to trigger: the subject-matter of the patent is not patentable; 148 the invention is not sufficiently disclosed to allow a person skilled in the art to carry it out; and the content of the patent extends beyond the content of the application as filed or, the patent was granted on a divisional application or on a new application filed under Art. 61, beyond the content of the earlier application as filed. 149 According to Art. 101 of the EPC, if the opposition is admissible, 150 the Opposition Division shall examine whether at least one ground for opposition under Art. 100 prejudices the maintenance of the European patent. 151 Decisions of the Opposition Divisions are subject to appeal to the EPO Board of Appeal. 152 Moreover, decisions to reject an opposition as inadmissible are also subject to appeal to the EPO Board of Appeal. 153 The opposition rate before the EPO is consistently higher in the closest available proxy for the pharmaceutical sector than it is in organic chemistry and all other sectors (overall EPO average). In 2015, overall, 2417 new opposition cases were filed in the EPO, with 1202 (inter partes) representing 52.6% of patents opposed. 154

Justifying the Patent Opposition Mechanisms
The theory that justifies the granting of a patent is based on the ''incentive to create''. 155 The principal basis of this incentive is to provide adequate compensation for the patentee. 156 This occurs by rewarding inventors with the right to try and exclude others from commercially exploiting their patented invention for a specific period 157 by taking two steps that they probably would not otherwise take: to invent in the first instance, and to reveal information to the public about their inventions. 158 This ensures that socially important products that, but for a patent, never would have been developed or would have been developed at a markedly slower pace, actually materialise or emerge at an accelerated speed. 159 While patents have been found to be significant in themselves as a component of the market value for economic growth, it is also true that the same can sometimes undermine the public interest if there are not adequate safeguards. Therefore, even the firmest advocates of the patent system must sometimes acknowledge that the legitimacy of the same relies upon two principal conditions.  First, it requires that valid patents be granted. Second, it necessitates that questionable patents be revoked or reduced to their proper scope. This is because the value that patent law provides society lies in stimulating original invention and rewarding the same with exclusive rights. As a matter of public policy, a patent must contain a non-obvious technical contribution to the state of the art, whereby a technical problem is solved by technical means, 160 and innovation and technological advancement are best served when an inventor is issued a patent with the scope of protection that is deserved. Therefore, resolving the issue of what is questionable should be a desirable feature of every serious patent system. 161 The opposition mechanism offers the opportunity to reduce the risk of patents being granted without sufficient scrutiny or to ensure that only innovations with valuable technology are worthy of receiving exclusive protection under patent law. 162 That is, the general patent policy in this direction seeks to ensure that the Patent Office does not grant, and the courts do not uphold, invalid patents.
As stated above, opposition proceedings are conducted before the Patent Office, 163 and the purpose of this is to give opponents, such as competitors, the opportunity to challenge the validity of patents. 164 This mechanism provides an additional, administrative layer of review, which is simpler than a court procedure or a quasi-judicial procedure. 165 To add to that, opposition proceedings have a shorter timeline and the involvement of technical experts who are well suited to navigate the complex scientific concepts embodied in patents. 166 It is also noted for being cost effective, as the procedure is a departure from the strictly formal set up of a court of law. 167 Uncertainty about the validity of a patent has several potential socio-economic costs. First, low quality patents can create considerable uncertainty among inventors or would-be commercialisers of inventions, which in turn can slow either the pace of innovation or investment in the commercialisation of new technologies. 168 Aside from being technically invalid, 169 commentators have argued that such patents are worthless 170 and burdensome on the patent system, 171 particularly in regard to the issue of unnecessary litigation. 172 It has been suggested that litigation can burden businesses. 173 One consistent study finds that pursuing litigation in highly dynamic markets risks producing an outdated final decision, as the market conditions that existed may have changed by the end of a full investigation and court proceeding. 174 A further core insight along this premise is that very few patents are litigated, and roughly half of all litigated patents are found to be invalid, including some of great commercial significance. 175 This contention is relevant given the empirical evidence suggesting that litigation by individuals and the government on patent validity is rare. 176 On this basis, it has been proposed in one sense that litigation as a socially optimal instrument for nullifying questionable patents is insufficient. 177 Although this assumption is not entirely novel in the literature, it structures our thinking that the use of litigation as an option for invalidating questionable patents may not always serve the public good given the possibility of settlement.
While perhaps never stated quite so bluntly, one strand of the literature that has tended to create a pessimistic view about the use of litigation as a medium of invalidating questionable patents suggests that a large percentage of litigation is settling for lawsuits for, basically, the avoided costs of discovery. 178 From a socially optimal standpoint, ''if they aren't transferring any technology in return'', as would often appear to be the case, as is commonly believed to be the norm rather than the exception, it is a bit hard to see how this behaviour serves the public interest. 179 Reasoning in ideal terms, the risk that a patent will be declared invalid is substantial because the amount a party is willing to spend on litigation closely correlates with that party's probability of winning an invalidity contest. 180 A reason for believing this is that asymmetric litigation costs may be used strategically to protect a questionable monopoly. 181 Therefore, for opponents in financially weaker positions, the effects of such a system are even more acute because of the ever-increasing costs of litigation. 182 Hence, the party with the deepest pockets is the one most likely to receive a favourable validity ruling. 183 Relatedly, two eminent observers of the patent system, Wright and Douglas, assert that litigated cases that end without a settlement generally result in either the defendant winning or the plaintiff withdrawing. 184 In this line, they further argue that the phenomenon of issuance of questionable patents not only raises the degree of actual uncertainty about the patent's claims but also increases the defendant's expected litigation cost. 185 One empirical study has suggested that even when litigation is initiated, most cases settle without a hearing. 186 While this notion depends entirely on the context, some scholars argue that if defendants choose to fight cases instead of settling, they are likely to prevail, or, instead, that defendants fight only cases they are likely to win. 187 The presumption that underlies this conclusion is based on the logic that settlement is less costly than litigation. 188 Here, the legal system is presumed to be a very expensive social institution. Therefore, the socially optimal result will normally favour a settlement rather than litigation. Contrary to this, Wright and Douglas advance two theses that work in harmony. First, an argument that settlements may lack the deterrent effect of litigation. 189 The second one manifests a contention that over-reliance on settlements rather than on litigation entails some social costs. 190 Professor Shavell puts this in the right perspective, as he argues that settlement allows injurers to pay less than they would were they to go to trial; therefore, settlement might undesirably dilute deterrence. 191 Added to the foregoing is the practical viewpoint that fear of litigation may cause smaller entrant firms to avoid areas where incumbents hold a large numbers of patents. 192 Such entry avoidance may be rational and even welfare enhancing if the incumbents' patents are known for certain to be valid. However, low quality patents held by incumbents may also deter entry into a technological area if the cost of invalidating the patents is too high. In these circumstances, technological alternatives may not be commercialised and consumer welfare may suffer. 193 This may also slow the pace of innovation in fields characterised by cumulative invention, in which an inventor's efforts rely on previous technical advances or advances in complementary technologies. 194 The key problem is ''evergreening''. 195 If these previous technical advances are covered by patents of questionable validity, the costs to inventors of pursuing inventions that rely on them may be so high as to discourage such cumulative invention. 196 This will eventually increase uncertainty among inventors concerning the level of protection enjoyed by these related inventions, which in turn will make it more costly and difficult for inventors to build on these related inventions in their own technical advances. 197 Following the foregoing logic, it is safe to argue for a self-checking mechanism in the market, where patents that have actual market power are legally challenged by competitors, who are often aware of the most relevant prior art and can probe beneath the surface of an applicant's affidavits and declarations. 198 More specifically, making firms more vigilant about their competitors' inventions would also encourage the dissemination of information contained in patent applications. 199 In this vein, parties with superior knowledge could challenge the validity of patents. 200 Thus, through the participation of third parties who may be well informed about the technology concerned, the opposition procedure would complement the examination procedure and increase the credibility of granted patents. 201 This is particularly important when individuals may not have the technical ability to supply evidence in challenging the validity of a pending or granted patent. 202 In this case, the burden of searching prior art would shift from the Patent Office to the inventor's competitors, who are likely to have better information. 203 Relatedly, the system could help educate examiners on issues presented by emerging technologies. 204 Because third parties are likely to have more knowledge of prior art in new fields, opposition proceedings could uncover areas unknown to examiners. 205 This mechanism could be used to target the most valuable patents; that is, patented inventions that are most likely to have an effect in the market are most likely to be opposed. 206 Moreover, the granting of questionable patents is also likely to spur significant increases in patent applications, further straining the already overburdened examination processes of the Patent Office. 207 A vicious circle may result, in which cursory examinations of patent applications result in the issue of questionable patents, which triggers a rapid swelling in applications, further exhausting the limited resources of the Patent Office, and eventually limiting the examination of individual applications, and further degrading the quality of patents. 208 Thus, the benefits of avoiding highly uncertain patents are sufficiently great that every patent regime must consider them. 209 In other words, since invalidating a patent provides a public good, typically to the benefit of competitors and consumers, one can naturally consider policies to enhance this regime. 210 This point reflects the theoretical view that at the heart of every successful IP system lies an elementary legal foundation and that the patent system operates to promote the fundamental interest of the public. 211 Importantly, while the current patent regime marked a new era of obligations regarding the protection and enforcement of patent rights, WTO members retained important policy options, including the right to protect their public interests. Therefore, the public interest norm, a principle on which the granting of patents rests, is captured by several provisions under TRIPS. 212 For example, the TRIPS Agreement unreservedly expresses the intent that the scope and form of a patent should be defined in a way that promotes the public interest. 213 Thus, the overriding objective of the public interest norm under TRIPS suggests that the meaning of the rule of law therein should conform to the underlying socio-economic welfare of the people, and that the Agreement was designed to serve, particularly, what is best for the national interest. 214 Within this spirit, Art. 8 of TRIPS allows member states to use their discretion when formulating or amending their laws and regulations, and to adopt measures necessary to protect the public interest. 215 This primarily follows Art. 8(2) of TRIPS, which envisages that such private rights stand to be abused by the right holders, and this will be detrimental to the legitimate public interest. 216 In fact, the wider discretion afforded to members to protect the public interest is established on the territorial foundation of patent law; that is, an internationally recognised norm that is qualified by several clauses under TRIPS. 217 Despite the common standards agreed upon by WTO members to protect patents, the territorial foundation of patent law remains intact, and TRIPS did not destroy this norm. This principle is grounded in the notion that every government has sovereignty within its borders or territories on patent law matters. 218 Thus, in relation to the principle of territoriality, and also subject to national treatment and the most favoured nation clause, 219 the scope of protection of a patent right is limited to the territory of the state where the right is granted, and justifies, for example, the exclusive jurisdiction of the authorities of the granting state with respect to questions related to the validity of rights conferred and their limitations. 220 Without any recourse to effective mechanisms to challenge the validity of patents, the public interest, a principle centrally established in the patent system, may be undermined. The opposition mechanism supports the conceptual viewpoint that granting patents without an effective quality control mechanism could potentially lead to negative spill-over effects on competition and innovation, not to mention adverse effects on economic growth. 221 That is, to say, a reasonable principle along this line would certainly have several merits including preventing a patent holder from enjoying a wrongful monopoly over a questionable patent to the detriment of the public. 222 The conclusions drawn from the failure of WTO members to explicitly include any operative provisions in relation to the patent opposition mechanism are firstly, an indication that individual members can exercise a certain amount of appropriate discretion on the subject, and secondly, that such a national action will be consistent and legitimate under WTO jurisprudence, and nothing in the light of TRIPS will, in fact, preclude the possibility of any country cleaning the patent system.

Conclusion
This paper has examined the need for states without any legal instruments to challenge the validity of patents to implement patent opposition mechanisms to mitigate the potential consequences of granting questionable patents. This is because while a great deal of importance is placed on the act of obtaining a patent itself, sometimes the necessity of checking the validity of patents remains less appreciated in certain countries, where the patent practice has focused extensively on the granting of patents rather than anything else. The need for an opposition mechanism seeks to reverse this, and is more supportive of the viewpoint that good patents are those with social value that promote the public interest. Put differently, the patent opposition mechanism is one central instrument whose normative foundation extolls the legislative wisdom requiring that the overriding public interest in the patent system is protected, since invalidly granted patents may potentially prejudice the same. That is, as an essential hallmark of the patent system, a potentially vital principle on which the granting of patent rights sits underlines the virtues that the patent system has always existed to promote rather than impede protection of the public interest. This view then destroys the accounts of patent advocates who have often concluded, without the benefit of evidence, that more patents are better for society even if they are weak. 224 Therefore, under the conceptual purview that the principal basis for granting patents embodies a utilitarian character, 225 a strong theme in this article has been premised on the argument that citizens in whose interests patents are granted have the right to participate in the patent system and to check that only inventions that fall within the fundamental interests of the public deserve exclusive rights. Consequently, drawing on the jurisprudence containing the substantive law and procedural requirements within the EPO and USPTO pursuant to patent opposition proceedings, it has been shown that if WTO members without patent opposition mechanisms were to explore and strengthen their regimes, citizens, competitors and other interest groups would be able to detect and invoke key provisions to challenge invalid patents while ensuring that the patent system is untainted and free of questionable claims for patents.