Common Grounds for Patent Invalidity : How to prove a patent in Invalid

Common Grounds for Patent Invalidity : How to prove a patent in Invalid

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Patents are granted to protect inventions, giving their owners exclusive rights to prevent others from making, using, or selling the patented technology. However, just because a patent is granted by a patent office does not mean it is permanently valid. Patents can be challenged and invalidated if they fail to meet the required legal standards.

Patent invalidity is a key aspect of patent litigation, licensing negotiations, and competitive business strategies. Understanding the common grounds for patent invalidity is crucial for companies defending against patent infringement claims, investors assessing the strength of a patent portfolio, and innovators ensuring their patents remain enforceable.

In this article, we will explore the most common legal grounds for invalidating a patent, along with real-world case studies demonstrating how these principles apply in practice.

Why Do Patents Become Invalid?

A patent may be declared invalid if it does not meet one or more of the fundamental legal requirements for patentability. In most jurisdictions, the key reasons for patent invalidity include:

  1. Lack of Novelty (Anticipation)
  2. Obviousness (Lack of Inventive Step)
  3. Non-Patentable Subject Matter
  4. Lack of Enablement or Insufficient Disclosure
  5. Lack of Utility
  6. Fraud or Misrepresentation (Inequitable Conduct)
  7. Prior Public Use or Sale Before Filing (On-Sale Bar)

Each of these criteria is legally defined and has been tested in numerous court cases worldwide. Let’s examine them in detail.

1. Lack of Novelty (Anticipation)

A patent is only valid if the invention is new at the time of filing. If an invention has already been disclosed publicly in any form before the patent’s filing date, it is not novel and can be invalidated.

Sources of Prior Art That Can Destroy Novelty:

  • Previously granted patents
  • Published research papers, books, or articles
  • Products available in the market
  • Public demonstrations or disclosures

Real-Life Case: Merck & Co. v. Teva Pharmaceuticals (2010)

Merck held a patent for a bone disease treatment drug (Fosamax). Teva Pharmaceuticals challenged the patent by proving that prior research papers had already described the drug composition before Merck’s filing date. As a result, Merck’s patent was invalidated for lack of novelty.

Lesson: If an invention was already publicly disclosed anywhere in the world before the patent’s filing date, the patent is invalid due to anticipation.

2. Obviousness (Lack of Inventive Step)

Even if an invention is new, it must also be non-obvious. A patent is invalid if an expert in the field could have easily arrived at the invention by combining existing knowledge.

Real-Life Case: KSR International Co. v. Teleflex Inc. (2007)

Teleflex sued KSR for patent infringement on a gas pedal system with an electronic sensor. However, the U.S. Supreme Court ruled the patent invalid, stating that it was an obvious combination of pre-existing technologies.

Lesson: If an invention is simply a predictable combination of existing ideas, the patent can be invalidated.

3. Non-Patentable Subject Matter

Certain types of ideas cannot be patented. Most patent offices do not grant patents for:

❌ Laws of nature (e.g., gravity, thermodynamics)

❌ Mathematical formulas (e.g., E=mc²)

❌ Abstract ideas (e.g., mental processes, software algorithms without technical implementation)

❌ Naturally occurring substances (e.g., human genes)

Real-Life Case: Association for Molecular Pathology v. Myriad Genetics (2013)

Myriad Genetics patented human gene sequences (BRCA1 & BRCA2) associated with breast cancer risk. The U.S. Supreme Court ruled that naturally occurring DNA sequences cannot be patented, invalidating Myriad’s patent.

Lesson: Natural discoveries and abstract ideas cannot be patented—only human-made inventions qualify.

4. Lack of Enablement or Insufficient Disclosure

A valid patent must contain a detailed description explaining how to replicate the invention. If the patent fails to teach a skilled person how to make and use the invention, it can be invalidated.

Real-Life Case: Ariad Pharmaceuticals v. Eli Lilly (2010)

Ariad sued Eli Lilly for infringing its gene-regulating drug patent. However, the court found that Ariad’s patent failed to provide enough detail on how the invention worked. The patent was invalidated for lack of enablement.

Lesson: A patent must clearly explain how the invention works—vague claims can lead to invalidation.

5. Lack of Utility (Patent Must Have a Useful Purpose)

A valid patent must cover an invention that has a practical use. If an invention does not work or has no real-world application, the patent can be declared invalid.

Real-Life Case: Perpetual Motion Machines

Numerous inventors have attempted to patent perpetual motion machines—devices that claim to produce infinite energy without external input. Since such machines violate the laws of physics, patent offices reject them for lack of utility.

Lesson: An invention must be functional—if it does not work as claimed, the patent is invalid.

6. Fraud or Misrepresentation (Inequitable Conduct)

If a patent applicant intentionally misleads the patent office by:

  • Withholding important prior art
  • Providing false data
  • Engaging in deceptive practices

The patent can be invalidated for fraud.

Real-Life Case: Therasense v. Becton Dickinson (2011)

Therasense (Abbott Laboratories) failed to disclose critical prior art when obtaining a patent for a diabetes testing strip. The court ruled this as intentional misconduct, and the patent was invalidated.

Lesson: Hiding relevant information from the patent office can lead to patent revocation.

7. Prior Public Use or Sale Before Filing (On-Sale Bar)

If an invention was publicly used or sold before the patent application was filed, the patent can be invalidated.

Real-Life Case: Pfaff v. Wells Electronics (1998)

Pfaff filed a patent for a computer chip socket but had already sold the invention six months before filing the patent application. The Supreme Court ruled that since the invention was on sale before filing, the patent was invalid.

Lesson: If you sell or publicly use an invention before filing, you risk losing patent rights.

Conclusion: Why Understanding Patent Invalidity Matters

For businesses, inventors, and legal professionals, understanding the common grounds for patent invalidity is crucial to:

  • Protect against weak patents that could be challenged in court
  • Conduct due diligence before acquiring patents
  • Defend against infringement claims by proving a patent is invalid

Key Takeaways

  • ✅ A patent must be novel – Prior art can destroy validity
  • ✅ It must be non-obvious – Simple combinations of existing technology are not patentable
  • ✅ It must be clearly described – A vague or incomplete patent can be invalidated
  • ✅ It must have a practical use – A non-functional invention is invalid
  • ✅ No fraud should be involved – Misrepresentation can revoke a patent
  • ✅ The invention must not be sold or used publicly before filing

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Patent Invalidity Search Report
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Prasad Karhad
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