Dr Rajkumar Singh
Initially, when the Coronavirus, the highly infectious disease, erupted in Wuhan, China, the two medicines, chloroquine and Hydroxychloroquine were recommended by several countries including India, China, South Korea and Italy for the treatment of Covid-19. In fact, Chloroquine is an anti-malarial medicine which is also used in some auto-immune diseases, but in the United States, hydroxychloroquine is more common in comparison to chloroquine. As these medicines were not approved through clinical trials, after initial use they were withdrawn from the possible treatment of Covid -19 infections. Further study in this regard also indicated negative results, but of the two, the hydroxychloroquine proved more effective and less harmful, although the WHO included both medicines as part of solitary clinical trial in its study scheme. In fact, the use of these medicines was discouraged due to its negative effects on human health.
Profile of Covid-19 medicines: In the fray of Covid-19 medicine was favipiravir and remdesivir. The first use and test of favipiravir was done in Wuhan, China, and it claimed the medicine to be more effective especially for patients who are in pre-ventilator stage. In an extensive study conducted in Wuhan on Covid-19 patients, it was found effective in cough and fever but in advanced stage of the disease it failed to give desired results. However, the Health Ministry of the Government of Italy has approved its generic version, named Avifavir, which proved effective in the initial stage of illness. Next to these was the medicine named Remdesivir, developed earlier during Ebola virus disease. It is mainly an anti-viral drug and helps control the premature breaking of chains, used presently as a possible treatment of post-infection stage. Till May 2020, it has passed phase three trials in several countries. This particular medicine has been used largely in US hospitals and provided the patients 31% faster in recovery time than other medicines as it makes patients recovered in 11 days in comparison to 15 days of earlier required periods.
Having fruitful results, the Food and Drug Administration (FDI) of the US Government has ordered its distribution through the licensed health care providers to treat adults and children who are being treated in hospitals. Under the provision of Emergency Use Authorisation, the government has given Gilead firm the responsibility of its distribution. The authorized agency has prohibited the use of remdesivir with chloroquine or hydroxychloroquine because it may reduce the anti-viral activity of remdesivir. Despite merits, the said medicine has two adverse effects or possible side effects (a). An infusion – related reaction has been detected during the infusion or around the time it was used and (b). In intensive test of liver blood, it was found that with its dose the level of liver enzymes increased which can cause inflammation or damage the liver cells. Its adverse health effects also include, respiratory failure, low albumin, low potassium, low count of red blood cells and elevated jaundice.
Further research on existing medicines: Traditionally, whenever a new type of infectious disease comes to the fore all available medicines used in the same type of disease are repositioned or repurposed keeping in view the need of the current disease. It’s a case of extensive/intensive research in which composition of each medicine is tested on the basis of symptoms inherent in the present illness for the therapeutic use of those medicines. To control and minimize the effects of Covid-19, several antiviral medicines developed and used previously during SARS, MERS, HIV/AIDS and Malaria are being researched and tested for the treatment of the pandemic in a big way. In the process mainly, safety and effectiveness of the medicines are evaluated in various phases of trial which may take months and years to final approval. In this emergency of Covid-19 the drug repurposing process was commenced in March 2020.The WHO took the lead role in repurposing a set of medicines for the treatment of Covid-19 patients. It was phase 2 and 3 trials aimed to benefit different diseases related to anti- inflammatory, anti- body, immune system, growth factor therapies to excess the prevailing supply chain and world-wide distribution. In a further development the United States Centre for Disease Control and Prevention also issued an advisory concerning remdesivir for those who are hospitalized due to pneumonia caused by Covid-19.
In general, the repurposing of medicines has to pass through three different rigorous stages In phase first, the safety and preliminary dose of the medicine is tested. In case of the present pandemic its therapeutic efficiency is evaluated with its ascending dose levels normally in hundreds of people. After the success in the first phase, second phase of testing begins in which randomized, placebo-controlled, blinded, are performed in different places with determining more short and effective doses and monitoring for its side effects. As per an estimate the success rate of phase two to three is commonly 31% while for infectious diseases is about 43%. The success of second stage does not give guarantee for the success in the third stage of research. Status as today: After the initial works began in March this year till mid-May 2020 several categories of preclinical or early-stage clinical research and development have been made in this direction. The major research areas relate to antibodies, anti-virus, cell-based compounds, scanning compounds with a large number of other therapy categories. However, till date no sound and full proof medicine has been found effective in treating Covid-19. In the context pre-clinical research is a beginning stage for the development of preventive vaccine, antiviral or other post-infection therapies. The experiments done so far has indicated the further safety and dose-related advancements for the treatment of Covid-19 infected people.
— The writer is Professor and Head, P G Department of Political Science, Bihar, India.