Recently developed pharmaceutical drug for life

Recently developed pharmaceutical drug for life
The Ebola virus disease (EVD) resurfaced in March 2014 as an epidemic in West Africa. Since then, it has spread to a multiple number of countries over a short period of time and qualifies as the largest Ebola epidemic in the history. This virus causes haemorrhagic fever in the victim and could be fatal. The virus easily transmits through direct contact with blood, body fluids and organs of the infected patient. The symptoms are difficult to detect as they are consistent with other viral infections, such as viral fever. According to World Health Organization, the fatality rate due to EVD is around 50%. In the previous outbreaks, the fatality rate has been known to be as high as 90%.[1]

Unfortunately, no licensed treatment or vaccination is available for EVD. In order to treat the patients infected with this deadly virus, the US Food and Drug Administration (FDA) has decided to accelerate the process for the approval of a drug called TKM-Ebola which until recently was in the experimental stage. This drug was developed by a Canadian company, Tekmira Pharmaceuticals Corp. and is in the pipeline for FDA approval by December 2014. Limited manufacturing of the drug has already begun.[2]

A previously used experimental drug named ZMapp, developed by Mapp Biopharmaceutical was used to treat seven EVD patients, of whom only five survived. ZMapp used a combination of monoclonal antibodies in order to boost the immune system and allow the diseased person to fight more efficiently against the virus. The success of ZMapp in humans has not yet been confirmed. Unlike this approach, TKM-Ebola uses RNA interference (RNAi) therapeutics.[3,4]

The basis of RNAi therapeutics is to inhibit gene expression, also known as gene silencing. This technique was discovered by Andrew Z Fire and Craig C Mello and was awarded the Nobel prize for physiology or medicine in 2006. The genomic sequence of the Ebola virus has been studied from various viral isolates. For the efficient working of RNA inhibiting molecules, drug delivery systems are required.[5] The need for this arises because siRNA is unstable and readily degrades in the presence of nucleases present in the body fluids. Also, they do not easily cross the cell membrane due to their negative surface charge.[6]

Tkm-Ebola uses the lipid nanoparticle (LNP) based delivery system. The drug molecules are encapsulated in lipid nanoparticles and administered through the intravenous route. The benefit of using LNP as a drug delivery system is to ensure efficient cellular targeting of the drug, to increase circulation time, and to reduce undesirable toxic effects and side effects; to name a few, siRNA remains stable for longer within the LNP and cellular uptake increases, thus increasing the bio-availability and efficacy of the drug.[7]

The RNA inhibitor molecules prevent the production of disease-causing proteins in the virus. These inhibitors are prepared using small interference RNA or siRNA. siRNAs are synthetic molecules designed for binding to specific target proteins. They form a complex called RNA induced silencing complex (RISC) which binds to the target protein. RISC destroys and suppresses the production of protein. The complex exists in a stable state within the cell for a number of weeks and results in the suppression of specific protein for an extended duration of time. This technique has been applied for the treatment of cancer and viral diseases like Hepatitis B, Ebola, etc.[8]

With the launch of this pharmaceutical drug, the Ebola epidemic may be successfully controlled. The reduction of the fatality rate would ensure life to many of the EVD victims. TKM-Ebola is an example of how new technologies like siRNA delivery and nanotechnology can be far more effective in the treatment of diseases than conventional technologies. With the advent of these potent mechanisms, fatal diseases like EVD can finally be controlled and cured.
How to cite this article:
Jahnavi Jha. Recently developed pharmaceutical drug for life. BioLim O-Media. 25 May, 2017. 5(5).
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