The first patent statute can be traced to Renaissance Italy, and since then the requirements for obtaining a patent have changed surprisingly little [1]. A patent is a government-granted right to be the exclusive maker, user, and seller of the new composition of matter or method. Today, the patent law system is a key engine for translating new inventions into broadly adopted advances in medicine.

This chapter provides an introduction to the patent system for medical practitioners. It begins with an example of a historically interesting medical device patent. It then describes the process of obtaining a patent, starting with actions to take while the invention is being made, progressing through filing a patent application and prosecuting it until it grants, and finishing with ways to monetize a granted patent. Each country has a slightly different set of requirements for patentability, and this chapter emphasizes US law while noting differing approaches in other countries.

In the 1930s, Frederic Foley was one of several inventors competing to make the first effective self-retaining balloon catheter. The balloon catheter had been envisioned as early as 1853, when J.F. Reybard introduced a device made of oil-dipped fabric attached to a balloon [2]. In 1927, Dr. Vincent Oddo tested a catheter design with a 5 cc rubber balloon attached to a two-way woven catheter [3]. However, Oddo’s approach proved unsuccessful because the rubber available at the time disintegrated upon contact with urine [3]. In the 1930s, Foley was a urologist in St. Paul Minnesota. His key innovation to the catheter was making the balloon and catheter from a single piece of rubber, resulting in a device that was stronger and cheaper to manufacture than earlier catheters. Foley presented his improved catheter at the 1935 meeting of the American Urological Association [2]. He did not patent it.

After settling on the catheter design, Foley struggled to find a commercially viable way to manufacture it, and ultimately filed for a patent on such a method in 1936 [4]. This method relied on a new manufacturing technology: dipping a form into latex rubber, pulling the latex-coated form out, and allowing the latex to dry on the form [2]. However, as often happens, a competitor had been developing the idea concurrently. Paul Raiche, working for the Davol Rubber Company, had independently developed the form-dipping method for manufacturing a wide range of rubber products, including balloon catheters. He applied for a patent on this method a few months before Foley did [4].

Despite a legal challenge by Foley, the patent office awarded a patent to Raiche and none to Foley. As a result, while the recognition for the Foley catheter went to Frederic Foley, the financial reward accrued to Raiche and his employer. Had Foley obtained a patent to the catheter or a method of using it, by filing the patent application before he publically disclosed the invention, he would have been in a position to obtain a royalty from the Davol Rubber Company, or even block them from manufacturing the catheter altogether. This example illustrates the importance of filing promptly on a new invention.

The first step towards obtaining a patent is recognizing that your invention can be patented. Almost any type of invention is eligible for patent protection. US law allows you to patent “any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof” but prohibits patents on laws of nature, natural phenomena, and abstract ideas [5]. More concretely, eligible inventions include new medical devices, diagnostic devices, new drugs, a new use of an old drug (e.g., to treat a different disease), or a use of an old drug at a new dosage or frequency. It is even possible to patent diagnostic methods, surgical procedures, and radiological procedures, although several countries make it difficult or impossible to patent these types of inventions. An unpatentable idea akin to a law of nature might be a discovery about the underlying mechanism of a disease, or a discovery about why a preexisting treatment actually works. However, when an inventor makes a “law of nature ” discovery, she often makes a patentable invention at the same time, for instance, by inventing a way to improve a preexisting treatment based on an understanding of how the treatment works.

A question that arises with every invention is: when is the invention ready to patent? The answer is that it’s ready to patent when you can describe the invention well enough so that a person skilled the relevant art (for example, in the case of a urological device, a urologist or a surgical equipment manufacturer) can make and use the invention [6]. This moment often comes earlier than an inventor might think. If the invention is a surgical device, it’s not necessary to have made the device. If the invention is a method of treatment, it’s not necessary to have used it on a patient. That said, if you have tested the invention, it is useful to describe the test results in your patent application. For instance, it’s useful to include results of a clinical study (even a small one), a test in an animal model, an in vitro model, or a computer simulation. A patent office generally requires much less experimental proof than a scientific journal does.

While developing a new invention, many inventors find it productive to share their ideas with colleagues. However, the patent laws of most countries impose severe confidentiality requirements on an inventor. In most countries, if the inventor publically discloses an enabling description of the invention (for instance, in an article or a seminar) before filing a patent application, the inventor is considered to have dedicated the invention to the public, and the invention is no longer patentable. For that reason, it’s important to keep the invention confidential until a patent application is filed. Confidential discussions between co-inventors are not considered public disclosures. If you need to discuss the idea with someone who is not an inventor, e.g., a collaborator at another institution, it is useful to have a confidentiality agreement in place before you discuss the substance of the idea.

Working with collaborators, such as university researchers or contract research organizations, raises additional questions. One is: who owns the idea? If you are in private practice, you generally own your invention. On the other hand, if you are an employee at a university or hospital, your employment agreement may give your employer ownership of any of your inventions that are related to your job. That’s not necessarily a drawback. If the institution owns the invention, they generally cover the cost of getting a patent and help find a licensee to commercialize it. Many institutions pay an inventor a flat fee per patent or a percentage of license royalties.

When there are co-inventors, each inventor (or their employer) is a joint owner of the patent application or patent. If you hire a contract research organization (CRO) to test or refine your invention, you probably don’t want them to become an owner of your patent. Many inventors negotiate a contract with the CRO that requires, if the CRO invents an improvement to the invention, the CRO assigns ownership of that improvement to the inventor. While questions of ownership can sometimes be sorted out after the patent application is filed, it is better to get a clear understanding of ownership early in the process.