Review of Therapeutic Candidates for the New Corona Virus Disease (COVID-19)

The World Health Organization has identified COVID-19 as a public health priority of international concern. Due to lack of effective antiviral drugs or vaccines, it is necessary to discover effective treatment methods (1). Recently, there have been reports of SARS-CoV-2 infection indicating that the virus is found not only in the respiratory tract but also in the gastrointestinal tract. Although ACE2 has been shown to play a key role in protecting individuals against lung damage and intestinal epithelial inflammation, it is interesting to note that ACE2 protein expression decreases after infection with the virus (2). SARS-CoV-2, like SARS and Mers, is a beta-coronavirus. The SARS-CoV-2 genome has been sequenced, and according to the genomic sequence, SARS-CoV-2 has a 96% identity similar to bat coronavirus and 79.6% similar to SARS-CoV. Although there is no approved drug or vaccine for COVID-19, a number of clinical trials are ongoing (3). The development of new drugs is a time-consuming process and generally requires several years of clinical validation. In recent studies, viral proteins have been used as the target of molecular docking-based virtual screening. The predictions of these studies help us to select appropriate laboratory and clinical candidate drugs (4). On the other hand, the use of drugs that have been approved for some diseases and are safe for human consumption should be evaluated for effectiveness against the new disease. In life-threatening cases, such a drug strategy is highly desirable if there is an alternative drug or vaccine. However, clinical trials are needed to ensure that such treatment is appropriate (5).

The aim of this study was to review therapeutic candidates for the emerging COVID-19 disease. This study is a review study as a narrative review which has been obtained by searching in valid scientific databases such as Scopus, Google scholar, PubMed using the keywords virus, Corona, COVID-19, SARS-CoV-2, treatment of the latest information. Also, to receive the latest information from reputable sites in the field of health, such as the World Health Organization and the Center for Disease Control and Prevention have been used.

Recommended medications to combat viral infections are including of remdesivir, chlorquine or hydroxychloroquine, Methylprednisolone, combination of ritonavir and lupinavir, Favipiravir, fingolimod and bevacizumab. Remdesivir is a drug that is an adenosine analog used to inhibit the action of RNA polymerase and is used for Marburg and Ebola viruses (43). Chloroquine or hydroxychloroquine is effective in inhibiting endosomal acid fusion (33,34). Methylprednisolone is a synthetic corticosteroid that binds to nuclear receptors to reduce proinflammatory cytokines (26). The combination of ritonavir and lupinavir acts as a viral protease inhibitor (40). Favipiravir is a guanine analog and is an RNA-dependent RNA polymerase inhibitor (46). Fingolimod is an immunological modulator and is mostly used in patients with multiple sclerosis and by binding to sphingosine 1 phosphate receptors, it reduces the outflow of lymphocytes from the lymph nodes (30). Bevacizumab acts against vascular endothelial growth factor (VEGF) to prevent hypoxia and inflammation caused by this factor in the respiratory epithelium (21). In addition to the above drugs, many drugs are currently being studied in different countries to confirm their effectiveness in treating COVID-19, which are listed in Table 3.

Due to the time-consuming nature of the development and registration of antiviral drugs, available treatments for other diseases may be the fastest emerging treatment option for infectious diseases. Broad-spectrum drugs such as bevacizumab, methylprednisolone, fingolimod, flupinavir, ritonavir, chloroquine phosphate, remedicivir, and favipiravir are currently being studied in various clinical trials as candidates for treatment. Therefore, it can be concluded that the use of all these drugs, in turn, can have a significant effectiveness in combating this disease. Of course, it should be noted that none of these drugs is the definitive and specific drug COVID19, and efforts to find a specific drug for this disease should continue until the definitive drug is available.