Under patent law, new uses of known substances can be protected by second medical use patents. It is known that the research in the field of medicine often leads to the discovery of new properties in known substances, thereby expanding areas of their application. For example, zidovudine, also known as azidothymidine (AZT), is a failed cancer treatment drug first synthesized in 1964 but approved two decades later as a treatment for HIV/AIDS. In its new implementation, it has formed the basis of global HIV treatment programs, extending the lives of millions of patients. Another instance is sildenafil citrate, originally designed to increase blood flow to the heart muscle and lower blood pressure. When tested again, the substance was found to significantly improve erectile function. This accidental discovery led to the creation of the world-famous drug Viagra, which was later patented in many countries.
The question on the validity of the Viagra patent was raised in many countries as:
UK (EP 0702555) by Lilly ICOS LLC;
EPO by Eli Lilly, Merck, Sanofi-Aventis, Bristol-Myers Squibb;
Australian patent number 676571 by Eli Lilly
Canada patent number 2163446 by Teva
In many jurisdictions, it is possible to obtain patent protection for a new medical use of the previously known substance. Meanwhile, the form that patent claims must take to comply with local practice, since it may vary considerably from country to country. On the other hand, in some jurisdictions, it may not be possible to obtain patent protection for a new medical use of a known substance. India, for example, appears to be fully opposed to attempts to obtain a patent for “evergreening” medicines. Accordingly, claims for a second medical use are not allowed. However, since chemicals and pharmaceuticals are subject to patenting in India, new formulation(s) of compounds can also be protected, but only if an “enhanced efficacy” of the drug is proven.
See Sect 3(d) of Indian Patent Act introducing the concept of ‘enhanced efficacy’ as a test for the patentability of incremental innovation, preventing evergreening; see also the case Novartis vs Union of India https://en.wikipedia.org/wiki/Novartis_v._Union_of_India_%26_Others
The known medical compounds may play a role in treating the coronavirus. For instance, the antiviral drug Remdesivir, which was originally developed against Ebola virus infection, was recently recognized as a promising treatment against a wide array of RNA viruses (including SARS/MERS-CoV5). Gilead sciences, holds patents on remedesivir and related compounds in several countries. However, Remdesivir is not yet approved as a drug in any country in the world. It is even still under clinical development for the treatment of Ebola virus infection.
How does Remdesivir work against corona virus?
The effectiveness of the Remdesivir against the coronavirus is in the property of its nucleosidic analogues to resemble natural molecules of nucleosides and to embed in the DNA and RNA of the virus. Small differences in the chemical structure of the virus’s nucleosides hinder its ability to replicate. Thus, it can be said that the drug punctures holes in the virus’s DNA and RNA, so it can no longer spread in the body.
Remdesivir is currently undergoing clinical trials against COVID-19 in hospitals in the USA, Germany, Canada and Japan. There, the medicine is available for patients with coronavirus infection as part of the drug treatment program. First, according to the American medical portal “Stat”, corona patients from Chicago hospitals, who were treated with Remdesivir, quickly recovered from fever and respiratory symptoms and were discharged from the hospital in less than a week. After success in the US, Remdesivir was allowed to be used on the recommendation of the European Medicines Agency (EMA) to treat some coronavirus patients who do not require artificial lung ventilation. In Germany, it has been observed that Remdesivir reduces and shortens the severe course of Covid-19 disease.
According to an analysis by the New England Journal of Medicine, clinical improvement was observed in 68% of COVID-19 patients treated by a Remdesivir.
Gilead Science is currently working with the regulatory authorities around the world to make Remdesivir more accessible through accelerated regulatory processes if it continues to demonstrate the potential for safe and effective COVID-19 treatment.