Authors: Martha Powell, Future Science Group
A trial assessing four Ebola treatments has highlighted two drugs that significantly improved survival rates: REGN-EB3 from Regeneron Pharmaceuticals (NY, USA) or mAb114 from Ridgeback Biotherapeutics (FL, USA). This has led to a recommendation that the trial be stopped early.
Four drugs were investigated in the Democratic Republic of Congo as part of the PALM trial, the two other drugs investigated were Mapp Biopharmaceuticals’ ZMapp and Gilead Sciences’ remdesivir (both companies CA, USA).
The trial, which had enrolled 681 patients as of 9 August 2019 out of a targeted 725, initially aimed to assess mAb114 and remdesivir against ZMapp as a control; the previous PREVAIL II study meant ZMapp was considered the standard-of-care. However, the trial was later amended to include REGN-EB3 based on a WHO recommendation.
This week, an independent data and safety monitoring board from the National Institutes of Health (MD, USA), recommended that the trial should be stopped early, and that future patients be randomized to receive wither mAb114 or REGN-EB3 as Ebola treatments. This was based on a preliminary analysis of 499 participants demonstrating that patients receiving these two drugs had a greater chance of survival compared with the other two treatments, at approximately 90%.
Moving forwards, mAb114 and REGN-EB3 will continue to be assessed as part of the PALM study’s extension phase, which will further evaluate safety. After this and expanded-access phase will be initiated using the lead therapeutics from the trial. REGN-EB3, is a cocktail of three monoclonal antibodies against Ebola whereas mAB114 is derived from a single antibody recovered from the blood of a person who survived Ebola in the Democratic Republic of Congo in 1995.
Sumathi Sivapalasingam, Senior Director, Early Clinical Development and Experimental Sciences at Regeneron, concluded: “This trial was conducted in difficult circumstances during a public health emergency, and we appreciate the efforts of the WHO and other experts to add REGN-EB3 to the trial. This trial is a remarkable advance in the decades-long struggle to respond to Ebola and we appreciate the tremendous efforts of the many governmental and non-governmental organizations who made it possible.”
Mike Ryan, Executive Director of the WHO Emergencies Programme, commented in a statement on August 12: “We are seeing outstanding results for those individuals who reach care early. The results for those who don’t reach care, or who reach care very late are still very poor. And they are reflected in the large number of deaths we’ve seen in this outbreak.”
“The success is clear, but there’s also a tragedy linked to this success. The tragedy is that not enough people are being treated. We are still seeing too many people staying away from Ebola treatment units, too many people not coming to hospital or not being found in time to benefit from these therapies.”
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