The coronavirus disease 2019 (COVID-19) is a highly infectious disease caused by a new strain of coronavirus the source of which has yet to be elucidated. The first case of COVID-19 was recorded in Wuhan, China in December 2019. As of April 24, 2020, the World Health Organization confirmed 2,591,015 cases of COVID-19 worldwide, including 178,686 deaths.[1] Of these, the Philippines reported 7,192 confirmed cases, including 477 deaths, 762 recoveries, and 5,953 hospital admissions.[2]

Governments throughout the globe have been trying to come up with their own solutions to curb the alarming rise of COVID-19 cases worldwide. These measures, which range from total lockdown to various levels of quarantine and social distancing, were designed keeping in mind the fact that, to date, there has yet been no scientific breakthrough on the COVID-19 treatment front. Understandably, there is no known specific medicine or vaccine to cure or prevent COVID-19 infection given that it is a newly-discovered disease.

Nevertheless, the international medical community is working double-time to find a COVID-19 cure. The world has taken to searching its medicine cabinets for potential cures. Some previously known substances and drugs for other ailments are now under investigation as possible treatments. Those that reveal promising results would be placed in the pipeline for testing through clinical trials in the hope of coming up with a cure for COVID-19.

A brief compilation of the more popular substances currently being considered and tested as possible COVID-19 treatments are the following:

Chloroquine and Hyroxychloroquine. Chloroquine has been around since 1934 and was initially used as an antimalarial agent and later for treatment of autoimmune diseases such as rheumatoid arthritis.[3]  Chloroquine has been found to possess antiviral activity against a multitude of viruses such as rabiew virus, poliovirus, HIV, hepatitis A and C, influenza, Chikungunya, Dengue, Zika and Ebola virus, among others.  Chloroquine interferes with viral binding to the cell surface receptor, as well as with the pH dependent entry of the virus into the cells and viral replication.[4]  Its analogue, Hydroxychloroquine is an oral medication that is used to prevent and treat malaria.[5] Hydroxychloroquine appears to work against malaria by increasing pH of vesicles within the cell, thereby curtailing the growth and reproduction of Plasmodium, the parasite which causes malaria.[6] In relation to COVID-19, hydroxychloroquine may act by blocking entry of viruses into cells, similar to what has been hypothesized for SARS virus, thereby reducing the viral loads of COVID-19 patients.

Azithromycin. Azithromycin is an antibiotic used to treat several kinds of bacterial infection. Instead of directly killing bacteria, azithromycin operates to intervene in bacterial reproduction.[7] It inhibits bacterial growth and reproduction by interfering with their protein synthesis. Azithromycin is used for the treatment of respiratory, enteric, and genitourinary infections, and may also serve as a first-line medication for certain sexually transmitted diseases and enteric infections.[8] Notably, the effect of hydroxychloroquine appears to be enhanced when it is used in conjunction with azithromycin.[9]

Favipiravir. Favipiravir is used for its antiviral properties, particularly against influenza viruses including strains that are resistant to existing anti-influenza drugs; as well as against a host of other  viruses such as flaviviruses (such as Dengue and Zika), and filoviruses (such as Ebola virus)[10], which are known to cause fatal hemorrhagic fever.  Favipiravir appears to work against RNA viruses (or viruses whose genetic material is composed of ribonucleic acid or RNA) by directly preventing its replication.[11] Thus, it is expected to be effective against coronavirus. The Japanese government has been testing favipiravir as treatment of COVID-19[12] while China has performed some clinical trials on the drug.[13]

Ivermectin. Ivermectin is a known drug used to treat several parasitic infections. It paralyzes and kills many parasites, such as Wuchereria bancrofti, Brugia malayi, and Mansonella ozzardi, all of which cause filariasisA study in Australia has demonstrated that ivermectin can stop SARS-CoV-2 growth in cell cultures.[14] Nonetheless, the process by which ivermectin targets and inhibits SARS-CoV-2 is still unknown.[15]

Remdesivir.  Remdesivir is a medication against several RNA viruses. It is used to treat filoviruses (such as Ebola), and coronaviruses (such as SARS-CoV and MERSCoV).[16] Remdesivir works by stopping the reproduction or replication of viruses.[17] In one study, treatment with remdesivir has shown clinical improvement in patients with severe COVID_19 symptoms.[18]  However, the actual efficacy rate of Remdesivir is yet to be confirmed.

Lopinavir-Ritonavir. Lopinavir-Ritonavir is an anti-viral medication for the treatment of HIV infection.[19] Since the combination of lopinavir-ritonavir is primarily formulated for treatment of HIV/AIDS, it has been shown to inhibit the formation of infectious viruses through their action as protease inhibitors, thus preventing subsequent waves of cellular infection.[20]

Are old drugs still patentable in the Philippines, albeit used for a different purpose?

Given that the drugs described above are being considered and tested as possible COVID-19 treatments, the question arises regarding their patentability under Philippine laws. It thus becomes necessary to examine relevant Philippine patent laws and rules to determine whether these drugs may be patented as COVID-19 medications.

Under Section 21 of the Intellectual Property Code of the Philippines (“IP Code”), “any technical solution of a problem in any field of human activity which is new, involves an inventive step, and is industrially applicable, shall be patentable.” Thus, a patent may be granted only if the following are present: (a) novelty; (b) inventive step; and (c) industrial applicability.

Sections 22.1 and 26.2 of the IP Code provide that the mere discovery of new use for a drug may not be granted a patent as it lacks the second requisite, i.e., inventive step. However, in its 2018 Revised Guidelines on the Examination of Pharmaceutical Applications Involving Known Substances (“QUAMA Guide”), the Intellectual Property Office of the Philippines recognized exceptions to Sections 22.1 and 26.2 of the IP Code, depending on whether the new use is inherently related to the originally disclosed use of the drug. Inherent new use of a known compound wherein the new result naturally and inevitably flows from the explicit disclosure in prior art, will be considered merely as a discovery, which is not patentable under the IP Code. Thus, the new use may be patentable if it is not inherently covered by or does not inherently result from a disclosure in a prior art relating to the drug.

Illustrations of the use of the doctrine of inherency in determining whether the new use of a known drug is patentable or not are as follows:

  1. If a compound (Compound X) is patented as an anti-cancer agent, its use as a treatment for lung cancer is not patentable because lung cancer is a more specific concept of the known medical use of Compound X;[21]
  2. If a compound (Compound Y) is patented as an anti-inflammatory medication, its use as treatment for pain is not patentable because the alleviation of pain is usually related to the prevention of swelling caused by infection;[22] and
  3. If product Z is patented as a herbicide and there is no prior art that discloses any therapeutic activity, its use as a treatment for asthma is patentable because even though product Z is a known substance, its use in medicine is not known.[23]

To further determine whether the new use of a known substance may be patented, the QUAMA Guide states that the “novelty” and “inventive step” elements should be carefully scrutinized. Thus, it appears from the QUAMA Guide that the discovery of a new use for a known substance may or may not be patentable depending on whether the new use is inherently related to the disclosed original use. Hence, any patent application relating to the new use should be carefully analyzed to determine the existence of the novelty and inventive step requirements.

In order to patent the new use of a known drug, the discoverer of such drug’s COVID-19 curative qualities must not only establish the three requirements for patentability. The discoverer must also convince the IPOPHL that said new use was not a mere discovery, or that the new use is not inherently covered by or does not inherently result from disclosed information related to the known substance. These requisites must be fulfilled, in order for a new patent to be granted, regardless of whether the patent of the known substance has expired or remains in force.