Patent Ever-greening has been largely used by the pharmaceutical industry for extending their patent protection. Industries generally use various legal and technological strategies to extend the term. Establishing or partnering with the generic establishment are some external strategies being used by the industries. But the majorly used strategy is the intentional minor modification of the old drugs thereby, obtaining multiple patents on the same drugs. The generic manufacturer provides the drugs at a much cheaper price. This forms a challenge to the originator who by way attempts to prolong the patent exclusivity and gaining credible market share. It leaves the generic with the only option to wait for the expiration of the term and then produce the generic drugs.

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Some of the common measures that are generally being used:

Enantiomers

The Enantiomers are heavily used by the pharmaceutical industry for ever-greening. Enantiomers are chiral molecules that are mirror images of one other. These two stereoisomers being the mirror images are non-superposable. Because introducing a new drug are costly, the industry tends to introduce enantiomers to extend the patent term. The best example can be Rilosec (omeprazole) and Nexium (esomeprazole) being two drugs used to control gastric hyperacidity, belonging to a similar class of medication. When Prilosec’s patent has been expired, Astra Zeneca Company introduced a drug named Nexium in 2001. The difference between the two drugs is that Prilosec is an equal (racemic) mixture of R- and Senantiomers but Nexium only consists of S-enantiomer. In other words, they are two isomers of one drug and they are only mirror images of each other, the one without R-enantiomer. (http://plg-group.com/ wp-content/uploads/2014/03/Pharma-Overview-Chemical-Engineering-News-Dec-2002.pdf).

New medical use of old drugs

A new medical use or drug repositioning is also a way for ever-greening of patents. This is doing a therapeutic switching of the old drugs for new medical indication especially for treating another disease. This is an efficient approach for saving excessive investment and gaining maximum profit from the same. Thalidomide, which was initially developed as a sedative and then used as a treatment for nausea and vomiting of pregnancy, caused over 10,000 severe birth defects (phocomelia) in children between 1957 and 1962. It was withdrawn due to phocomelia, but it was approved by the US Food and Drug Administration (FDA) for treatment of leprosy complications and multiple myeloma (bone marrow cancer). (Vargesson N, Thalidomide-induced teratogenesis: History and mechanisms, Birth Defects Research Part C, Embryo Today, 105 (2015) 140-156).

New Route for Administration

Even to the extent, various companies also resorted to changing the route of administering the drug and were successful in claiming the patent over it. A migraine drug known as Imitrex was given in the tablet form for oral administration. The company reformulated the administering route and change it to intranasal delivery (nasal administration). Even if the patent expired in 2006, the company extended the patent protection term till 2009 by presenting the nasal spray for the drug giving a total sales of US$1 Billion for the company.

Analysis

According to Section 3(d) of the Patents Act, new forms of salts, esters, polymorphs, metabolites, change in particles size of drugs, the difference in isomerism, isomers mixture, complex formation, a combination of drugs and drug derivatives, do not consider as new drugs and cannot be patented, unless a significant change on the therapeutic properties of drugs has occurred or these changes directly affect a great deal on the “efficacy” of the drugs. Hon’ble Supreme Court in the famous case of Novartis a.g. vs. Union of India, has reiterated that the main intention of the section was to restrain the process of ever-greening of patents by pharmaceutical companies. According to the Supreme Court, restraining the practice of ever-greening will lead to the emergence of generic forms of costly medicines that will help the general customers. Novartis was unable to prove that the therapeutic efficacy of the drug has increased.