United States: Federal Circuit's Primer On Equivalence Infringement Of Chemical Process Patents

In an appeal characterized as "unusual," the Federal Circuit affirmed the grant of a preliminary injunction, holding it likely that plaintiff patent holder would succeed on the merits its claim of infringement of a patent claiming a purified chemical compound, but reversed a finding of infringement under the doctrine of equivalents of related chemical process patents. Mylan Institutional LLC v Aurobindo Pharma Ltd., 2017-1645 (May 19, 2017 Fed. Cir.). The decision is an interesting read because, as the court admitted, "of the sparse and confusing case law concerning equivalents, particularly the paucity of chemical equivalents case law, and the difficulty of applying the legal concepts to the facts." Slip Op at 12.

Processes for Preparing Isosulfan Blue (ISB) and the ISB Product

Apicore is the owner of three patents: U.S. Patent Nos. 7,622,992 ('992 Patent) and 8,969,616 ('616 Patent) that relate to processes for preparing isosulfan blue ("ISB"), and U.S. Patent No. 9,353,050 ('050 Patent) that claims a purified compound having greater than 99% purity as measured by high performance liquid chromatography (HPLC). All three patents share the same patent specification. Mylan Institutional LLC (Mylan) is the exclusive licensee of the three patents.

ISB is a dye for mapping lymph nodes. The '992 and '616 Patents relate to a process for preparing ISB by reacting isoleuco acid with silver oxide in a polar solvent. The product is subsequently reacted with a sodium solution. The claims of the '616 and '992 Patents are identical, except the '992 Patent also requires 2.0-3.0 equivalents of silver oxide.

Apicore's patented process produces ISB having a purity greater than prior art ISB products. Apicore received FDA approval to market the product and ultimately, competitors abandoned the market.

Defendant Aurobindo also sought FDA approval for an ISB product and told the FDA that it had studied the '992 Patent and that it had optimized the claimed process by substituting manganese dioxide for silver oxide used in the '992 Patent process. Aurobindo also used HPLC to achieve a purity of greater than 99.5%.

Mylan sued Aurobindo for infringement and sought a preliminary injunction, which the Eastern District of Texas granted.

Infringement Under the Doctrine of Equivalents and Injunctive Relief

Aurobindo sought on appeal reversal of the district court's finding that Aurobindo more likely than not infringed the '616 and '992 Patents under the doctrine of equivalents.

A court will grant a preliminary injunction only when the plaintiff can establish "that [the plaintiff] is likely to succeed on the merits, that he is likely to suffer irreparable harm in the absence of preliminary relief, that the balance of equities tips in his favor, and that an injunction is in the public interest." Slip Op. at 10, citing, Winter v. Natl. Res. Def. Council, Inc., 555 U.S. 7, 20 (2008). With that in mind, on appeal the Federal Circuit evaluated the district court's finding of infringement under the doctrine of equivalents.

Aurobindo argued that it had raised a substantial question of infringement of the '616 and '992 process Patents, because the use of manganese dioxide is different from the use of silver oxide claimed in the patents. Manganese dioxide is a stronger oxidizing agent and requires the use of an acid, which the patents specifically report is not necessary with the use of silver oxide. Aurobindo also disputed Mylan's argument (supported in large part by an expert testimony), that if "manganese dioxide was a substantially stronger oxidizing agent than silver oxide, a skilled artisan 'would expect different results.'" Slip Op. at 11.

The Federal Circuit agreed with Aurobindo that the district court's analysis was erroneous. The court first noted that in chemical cases, the function-way-result (FWR) test ("viz., whether the accused product performs 'substantially the same function in substantially the same way to obtain the same result'" Slip Op. at 12) is not well suited for the chemical arts. The court noted that for chemical cases, the insubstantial differences test ("whether the accused product or process is substantially different from what is patented") may be more suitable.

The Federal Circuit determined that the "function" prong of the FWR test was not met because of the difference in oxidation strength between silver oxide and manganese dioxide was not considered by the district court. In addition, the Federal Cirsuit held that the district court erred in failing to address the "way" prong of the FWR analysis – "having considered the relative oxidation strengths to be an issue for claim construction, and rejecting Aurobindo's arguments about oxidation strength because it had not argued for a narrow claim construction – or it performed a 'way' analysis without considering critical factors under the prong, namely, the relative oxidation strengths of silver oxide and manganese dioxide, as well as the use of an acid in the accused process." Slip Op. at 15-16.

The Federal Circuit determined that manganese dioxide and silver oxide do not function in the same way, noting the relative oxidation strengths of the two oxidizing agents and the fact that manganese dioxide requires the use of an acid for oxidation, while silver oxide does not. The court concluded that "[t]hus, there is room for sufficient doubt as to whether silver oxide and manganese dioxide oxidize isoleuco acid in the same way so as to satisfy the 'way' prong of the FWR test." Slip Op at 16.

As a tutorial, the court went on to illustrate how the FWR test is ill suited for chemical patents. Taking aspirin and ibuprofen, two structural different compounds, as an example, the court noted that the compounds could be considered equivalents under the FWR test because they each provide analgesia and anti-inflammatory activity ("function") by inhibiting prostaglandin synthesis ("way") in order to alleviate pain, and reduce fevers and inflammation ("result"). In contrast, under the substantial differences test, the distinct chemical structures of the two compounds would establish that they are not equivalents.

Applying the substantial differences test to the facts at hand, the Federal Circuit noted that manganese dioxide and silver oxide are substantially different in many respects. They are in different groups of the Periodic Table and they have different oxidation states. Slip Op at 18. Thus, under this test, they are not equivalents.

The Product Patent

Aurobindo had challenged the validity of the '050 Patent on three grounds: 1) that the claims were anticipated by the prior sale of a similar product by Sigma; 2) that the claims were over obvious over the prior art; and 3) that the claims were indefinite in reciting the term "having a purity of at least 99% by HPLC."

On anticipation, Aurobindo's challenge failed because the court found that the evidence supporting the anticipation argument was not credible. Aurobindo relied on Sigma's manufacturing literature that was determined to be unclear and contradicted by other Sigma literature.

The Federal Circuit also found the obviousness argument without merit because the process to obtain the compound of the '050 Patent was itself of patentable weight, and thus the claims would not have been prima facie obvious over the prior art.

The Federal Circuit rejected the indefiniteness argument noting that HPLC is a well-known and common means to determine purity.

Finally, the court gave weight to Mylan's evidence of secondary considerations supporting non-obviousness of the patent of long-felt but unmet need, commercial success, copying/praise of others, and unexpected results.

Preliminary Injunctive Relief

While Aurobindo prevailed in reversing the finding of infringement under the doctrine of equivalents of the '616 and '992 Patents, its failure to reverse the finding of validity of the '050 Patent led them to the same place – their manufacture and sale of ISB was enjoined.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

Authors
 
In association with
Related Video
Up-coming Events Search
Tools
Print
Font Size:
Translation
Channels
Mondaq on Twitter
 
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
 
Email Address
Company Name
Password
Confirm Password
Position
Mondaq Topics -- Select your Interests
 Accounting
 Anti-trust
 Commercial
 Compliance
 Consumer
 Criminal
 Employment
 Energy
 Environment
 Family
 Finance
 Government
 Healthcare
 Immigration
 Insolvency
 Insurance
 International
 IP
 Law Performance
 Law Practice
 Litigation
 Media & IT
 Privacy
 Real Estate
 Strategy
 Tax
 Technology
 Transport
 Wealth Mgt
Regions
Africa
Asia
Asia Pacific
Australasia
Canada
Caribbean
Europe
European Union
Latin America
Middle East
U.K.
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.

Disclaimer

Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.

Registration

Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.

Cookies

A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.

Links

This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.

Mail-A-Friend

If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.

Security

This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.