Tuesday, December 30, 2014

EBOLA treatment: Convalescent plasma therapy (CPT) Gaining Momentum

Convalescent plasma therapy (CPT)

This is not new but old techniques, but seriously discussing and researching now a day. A couple of days back NPG reported about the ongoing clinical research in CPT. The CPT, earlier really helped to reduce the fatality of N1H1 victims. Now the same approach is trying with EBOLA victims. 

Clinical trials of convalescent plasma therapy (CPT) have started in the past few weeks in Liberia, and are due to begin soon in Guinea and Sierra Leone. If the therapy saves lives, the approach could quickly be scaled up. 

Success would also raise awareness of CPT’s potential to treat other new and emerging infectious diseases for which there are no readily available effective drugs or vaccines, such as SARS, avian influenza and Middle East respiratory syndrome (MERS). “Clinical trials of convalescent plasma should be considered in other emerging infections,” says David Heymann, an infectious-disease researcher at the London School of Hygiene and Tropical Medicine, and chair of Public Health England. 

What is Convalescent plasma therapy (CPT) ?

Basically this is a plasma transfusion treatment. The plasma will be collected from patients who recovered from the infection. Only plasma with a high neutralizing antibody will e used. The treatment involved an infusion of 500 mL of plasma over a four-hour period on day two of the stay in the intensive care unit. To the extent possible, the treatment and control groups were matched by age, sex, comorbidities, and disease severity at ICU admission. 

Nonetheless, patients in the treatment group had more risk factors for severe disease, including a lower lymphocyte count, greater prevalence of obesity, and presentation with more severe symptoms. 

Convalescent plasma therapy, which is safer now than in the early half of the 20th century because of donor screening, virological and microbiological testing, and apheresis, may have some advantages over antivirals.

Collecting convalescent plasma presents some feasibility issues during the course of an epidemic because the plasma will not be available at the beginning of the outbreak.

Convalescent plasma therapy (CPT) Gaining Momentum

Many scientists have long argued that CPT has been wrongly neglected, both as a therapy for emerging diseases and in preparation for future unknown threats. Today, the approach is gaining ground. Trials of convalescent plasma are beginning for the treatment of patients with MERS, which has infected 938 people and killed 343 of them since it was discovered in 2012. And an international protocol aimed at removing hurdles to quickly rolling out trials of convalescent plasma has recently been drafted.

CPT Where and When ?

Convalescent plasma was found to effectively treat diphtheria and tetanus at the end of the nineteenth century, and was widely used in the first half of the twentieth century to treat diseases such as measles, mumps and pneumonia. But it fell off the radar after the development of antibiotics, antiviral drugs and vaccines. (An exception was the adoption of CPT in Argentina for Argentine hemorrhagic fever after a successful controlled trial in the 1970s.)

When available , vaccines and drugs are the best option. CPT is a lengthy and risky procedure, and may be not able to cover a large population with ease. In other case , drugs and vaccine can be mass produced and easily applied during and out break.

CPT is more complicated — it requires collecting survivors’ blood, screening it for pathogens and then organizing patient transfusion. And standardizing batches of plasma is difficult, because antibody levels in donated blood can vary widely.

But an epidemic or pandemic of a new pathogen turns that logic on its head. As in the case of the Ebola epidemic, there are typically no drugs or vaccines available, and developing these usually takes years. By contrast, “convalescent plasma is one of the few things you can get up and running quickly”, says Calum Semple, a paediatrician and clinical virologist at the University of Liverpool, UK, who is involved in the Guinea Ebola trial. Trials for Ebola and other emerging diseases “should have happened years ago”, he adds. He points out that the therapy is often considered old-fashioned and that there are neither big profits to be made nor cutting-edge-science interests at stake. “Convalescent plasma is not attractive to pharma, or the modern model of academia,” he says.

Adequate screening for pathogens in donated blood can be an issue in poorer countries. In the CPT Ebola trials, a chemical is being added to the donated blood. When the mixture is exposed to ultra­violet light, the compound irreversibly crosslinks the DNA and RNA of pathogens, preventing their replication.

Hope advancement in CPT may bring control over new epidemic outbreaks. Hope the human race may gain the ability to stand with their own mistakes.

About the Author

Prejeesh Sreedharan

Author & Editor

I am a Biotechnologist very much interested in #SciTech (Science And Technology). I closely follow the developments in medical science and life science. I am also very enthusiast in the world of electronics, information technology and robotics. I always looks for ways to make complicated things simpler. And I always believes simplest thing is the most complicated ones.

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