Patents are a key form of intellectual property (IP). The term “intellectual property” contains the word “intellectual” for the reason that one exerts mental effort in order to create an invention. Patent law then steps in to protect an inventor’s mental creation and places restrictions on similar inventions or ideas to allow the inventor to reap the fruits of his or her labors.

The patent system preserves and rewards creativity and thereby encourages inventors to innovate. In the context of the pharmaceutical industry, it serves as the driving force behind the development of new drugs.

Generally speaking, innovator pharmaceutical companies develop novel drugs, whereas generic pharmaceutical companies copy existing drugs and sell them at lower prices. Generic drug companies can, however, only copy drugs that are not protected by a patent—for example, in an instance where a patented drug product’s term has expired. By patenting a drug, a patent owner has the exclusive right to distribute it for a specified period of time—commonly 20 years in Thailand, which cannot be extended.

As is the case with other inventions, drugs that are only slightly different from existing ones have been successfully patented. This process is known as “evergreening,” which is done effectively to extend a patent term by a patent owner filing an application for a new product that has only minor differences compared with the previously patented drug.

For instance, a pharmaceutical company could file a patent for a drug with slightly altered chemical properties claimed to improve on certain aspects such as chemical stability or efficacy. It has been argued that such variants on existing products block the development and production of legitimate generic drugs, and many see this as a trick by pharmaceutical companies to stretch out the patent term, with the altered properties doing little actually to improve the drug.

However, the mere filing of a patent that is similar to one already issued is not necessarily a trick to extend the patent term. Often, the new patented drug provides an important and genuine, albeit minor, innovation such as reduced side effects, greater safety, or heightened efficacy.

Also, an originally patented version of a drug will still expire and be open to generic reproduction, and generic companies can make a product similar to one that has an expired patent. Thus, an improved version of a drug can be considered an incremental development that leads to a better quality of life for patients rather than as a trick to extend the lifetime of a patent term.

New drugs generally are not discovered overnight but rather through a series of small improvements on a previous drug. There are also numerous benefits to incremental innovation—slight modifications to a drug formula can provide benefits such as preventing allergic reactions or other side effects or an easier manufacturing process.

Nonetheless, several countries consider evergreening detrimental and have developed anti-evergreening laws in response to the practice. In countries with heightened novelty requirements for pharmaceuticals, it is very difficult to patent drugs with incremental improvements.

India, with its large generic drug industry and a huge population requiring access to low-cost medications, is one example of a country that has anti-evergreening laws. Section 3(d) of India’s Patent Act is the first and most extreme anti-evergreening provision. Under Section 3(d), variants on a patented pharmaceutical product are not patentable unless there is a “significant” improvement of efficacy. Innovation that merely results in better drug stability or easier drug administration is not considered a significant improvement and is therefore non-patentable in India.

Thailand’s Patent Act has no provision limiting the scope of patentability for incremental innovations. The IP Department has, however, devised chemical and pharmaceutical patent examination guidelines to discourage patent filings for drugs that do not possess the requirements of novelty or an inventive step taken by a pharmaceutical innovator.

These examination guidelines have existed since September 2013 and heightened the department’s standards when it comes to determining whether a product provides a patentable innovation over previous patents. The department anticipates the guidelines will hasten the patent examination process.

So far, however, the guidelines have led to numerous applicants encountering challenging examination results or “office actions” from the IP Department as to whether their inventions are considered to be evergreening. Thus, applicants are advised to review their patents carefully and consult with patent lawyers to overcome any rejections, questions or requests for additional documents.

While anti-evergreening provisions may discourage innovation, incremental innovations resulting in a similar drug may not be beneficial to a country and could block the development and production of legitimate generic drugs. A thorough and well-balanced examination of patent applications should be the middle road for granting exclusive rights to an inventor.