Is Remdesivir a cure?
Different treatments are considered in the fight against COVID-19.Remdesivir is one of them.It is the first antiviral that effects against COVID-19.Remdesivir treats COVID-19 as an antiviral and antiflammatories.It is used for critically ill patients of below 94% oxygen level.Remdesivir which is also known as GS-5734 is a broad spectrum antiviral used against single strand RNA viruses.It was developed in 2009 to treat Hepatitis C.It was used against Ebola virus few years back during Ebola virus epidemic,but found less affective later.SARS-CoV-2 is the virus that is responsible for COVID-19.Remdesivir has shown some effect on SARS-CoV-2.It also effects on virus like SARS-CoV and MERS-CoV.
Remdesivir is a produg of GS-441524.This GS-441524 is an adenine analogue which is used to create or produce nucleic acid like DNA and RNA.Basically Remdesivir is an inactive medicine but when it is put in body it becomes metabolized into active form that is GS-441524.It targets RNA dependent RNA polymerase(Polymerase is an enzyme that brings about the formation of particular polymer especially DNA and RNA) which is basically one of the mechanism that the virus uses to make copies of itself.That is how Remdesivir act to shut down viral replication.It is found that there is 30% improvement in people who had Remdesivir.It is sold under the brand name veklury and is developed by biopharmaceutical company named Gilead.Gilead is conducting two randomized,open-label,multicenter, Phase 3 clinical studies to evaluate the safety of two dosing durations of remdesivir in adults diagnosed with COVID-19.
Let’s find out how a virus replicate itself in a host cell first.
When a host cell comes in a contract with the SARS-CoV-2,it infects that cell by certain mechanism.SARS-CoV-2 has protein on its surface which are known as spike or S protein.This S protein binds with ACE2 receptor on the cell membrane of a host cell.
SARS-CoV-2 then invaginates into host cells which means it has an inward movement of a portion of the wall of a blastula in the formation of gastrula.It brings the virus in endosome but often time fuses with a lysosome.This whole process is known as endocytosis process (the taking in of matter by a living cell by investigation of its membrane to form a vacuole).Than the virus exists out of the endosome or lysosome and unreveals its viral RNA.This viral RNA is the genetic code of SARS-CoV-2.It is a single strand RNA as mentioned before.
Once it is inside the cell it heists the host cell machinery like ribosome (Ribosomes are the protein maker of a cell).Ribosomes translate that viral RNA into RNA-Dependent-RNA-Polymerase (RDRP).It is RNA dependent because it needs RNA to function and RNA polymerase because it makes more viral RNA.Through RDRP SARS-CoV-2 viral RNA produce the viral proteins like capsid,spike protein,membrane protein,envelope protein.This protein flows to golgi apparatus through endoplasmic reticulum and makes a new SARS-CoV-2.It then came outside of the cell membrane of host cell and effects more cell.Thats how this SARS-CoV-2 spreads in other cells.
Now,lets find out how Remdesivir stops this viral replication.
After taking Remdesivir via I.V.(Intravenous administration),it enters into cell,then metabolized to its active form GS-441524.Viral RNA has four nucleotide bases such as A(Adenine),G(Guanine),C(Cytosine),U(Uracil).As mentioned before GS-441524 is a adenine analogue,it means it mimics like adenine of that viral RNA adenine but it is not.Because of that GS-441524 the RDRP becomes confuse.It makes new replication taking the GS-441524 instead of viral RNA adenine.Then the new replication becomes defective and essentially inactive.Thats how Remdesivir inacts its antiviral effects by inhabiting viral RNA production.
Wait…
There is something more.The SARS-COV-2 viral RNA has a proof reading ribonuclease.It is a part of the original viral RNA,known as 3`-5`exoribonuclease (ExoN).This ExoN actually detects the defective part and fixes that in the replicated viral RNA strand.It removes the defective piece and allows RDRP to continue to make viral RNA.So,we can say that ExoN is effecting against Remdesivir.
So,we can see that though Remdesivir shows effect against SARS-CoV-2 but it is not a vaccine.Remdesivir has been shown to have antiviral effects against SARS-CoV and MERS-CoV in in-vitro studies in human epithelial cells.It can only stop the virus spreading inside the body.
