Clinical drug trials of an experimental treatment for Ebola have stopped after it was found unlikely to be effective. Health officials have been looking to abate the effects of the virus strain that has ravaged West Africa for more than a year.
Last week, Vancouver-based Tekmira Pharmaceuticals Corp. announced it was no longer enrolling patients into its Phase II clinical trial of its experimental drug TKM-Ebola-Guinea, stating that “continuing enrollment was not likely to demonstrate an overall therapeutic benefit.”
The company said that it would provide results of its data analysis of the trial “as soon as possible,” and that any decisions regarding the future of the drug would be based on the findings.
The drug was developed to treat the particular Ebola virus strain responsible for the largest outbreak of the disease. Researchers determined the virus was a new form of the disease last spring, when blood tests from patients in Guinea showed the strain had a high similarity to the “Zaire” strain found in central Africa, but was found not to have been imported from that region.
Trials for TKM-Ebola-Guinea began in March in Sierra Leone. The area has cumulatively experienced the largest number of cases since the start of the outbreak at more than 12,900 as of June 17. According to the World Health Organization. Sierra Leone has the highest total of newly infected cases among any of the affected countries in West Africa, where 41 were reported over the past 21 days, the WHO found.
“It is a great tribute to the team in Sierra Leone that the trial has been run so efficiently and that we now have substantial experience on the use of TKM-Ebola-Guinea in patients with Ebola,” study chief investigator Dr. Peter Horby, associate professor of Infectious Diseases and Global Health at University of Oxford, said in a written statement. “While the trial has reached a statistical endpoint, final conclusions on the efficacy and tolerability of the drug must await full analysis of the data.”
The results highlight the difficulty in developing an antiviral treatment or a vaccine for Ebola. There currently are no approved treatments, and without immediate and sustained supportive medical care, a patient's chances of survival is slim, as been highlighted by the current outbreak, where the death rate has been about 71%.
In an e-mailed response to questions, Tekmira representatives stated that halting the TKM-Ebola-Guinea trial has not affected the progress of its other Ebola-related trial. That's for an earlier version of the drug that the company has been developing under a $140 million contract with the U.S. Defense Department.
Last August, the Food and Drug Administration eased a clinical hold it had placed on Tekmira's TKM-Ebola, allowing for testing in infected human patients. The product is being evaluated in healthy subjects as part of a multidosing trial, the company stated.