Treating diseases caused by viruses is complicated. In the case of covid-19, after many trials, it has been seen that remdesivir can reduce the length of hospitalization by a few days if given to hospitalized patients who require oxygen. On the other hand, dexamethasone, a drug with anti-inflammatory effects, prevents about 30% of deaths in severe patients. Although there have also been many studies with antibody-based treatments, there are currently no solid enough results for any of them to be approved. A new trial done in Argentina and published by the New England Journal of Medicine provides a higher degree of evidence than the rest of the studies completed so far regarding these treatments.
The trial, coordinated by the INFANT foundation, involved 160 patients with covid-19 over 65 years of age and with an average age of 77. All had at least one chronic disease such as diabetes, obesity or hypertension, among others. Half of the participants were treated with blood plasma belonging to people who had already had the disease and the other half were given a placebo, i.e. a substance that contains no active ingredient from a pharmacological point of view (in this case, water with mineral salts). The plasma used, in addition to having a high amount of antibodies, was injected in the first 72 hours after the onset of symptoms. Of all the patients who received plasma, nine required oxygen. Of the rest, 23 required it. This indicates that, administered under these conditions, plasma from recovered patients can reduce the progression of the disease to severe cases by 60%.
As the authors explained in a statement, "this study describes the world's first strategy to stop the progression of SARS-CoV-2 with a non-proprietary, cost-effective intervention that has been proven safe and can be administered on an outpatient basis without the need for hospitalization. According to Anna Millan, care director of the Blood and Tissue Bank, "although this has not been done with a very high number of patients, it can be concluded from this study that treatment with plasma belonging to people who have had the disease can work if it is applied early and if the plasma has high levels of antibodies".
A difficult treatment to try
The principle of how this treatment works is simple: since recovered people have antibodies in their blood that protect them from new infections, if these antibodies can be removed and introduced into patients, the prognosis of the disease could be improved. The problem during the pandemic is that not enough studies have been done with large numbers of people to demonstrate the effectiveness of this principle conclusively. "Getting these studies up and running takes time", Millan explains. And to do them also requires a considerable and sustained number of infections over time, which of course we are trying to avoid. One of the largest patient studies ever done in the United States found that the treatment was safe in 35,000 patients. However, since no placebo was given to any of the participants, it could not be concluded whether the patients who improved did so as a result of having received plasma or because of other factors.
The use of plasma from survivors is the cheapest option for administering antibodies to patients. One alternative, on which the Catalan pharmaceutical company Grifols is working, is to obtain a substance with a high concentration of antibodies extracted from the blood of surviving donors with the aim of preparing a drug known as hyperimmune globulin. It is also possible to use so-called monoclonal antibodies, which are antibodies created in the laboratory from antibodies generated by people who have had the disease, and which is the most expensive antibody-based treatment of all.
Presently, the plasma received from the Blood and Tissue Bank is classified according to antibody concentration for use in a clinical trial at the Germans Trias y Pujol Hospital. "We are carrying out a campaign to receive donations, with the idea of building donor loyalty", Millan explains.