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NEW YORK, Nov 26 (Reuters) - An experimental Ebola vaccinemade by GlaxoSmithKline caused no serious side effectsand produced an immune response in all 20 healthy volunteers whoreceived it in an early-stage clinical trial, scientistsreported on Wednesday in the New England Journal of Medicine.
The trial, which began on Sept. 2 and will monitor thevolunteers for 48 weeks, is primarily aimed at assessing howsafe the vaccine is. But the immune response offered hope thatit would also be effective.
"The safety profile is encouraging, as is the finding thatthe higher dose of vaccine induced an immune response quitecomparable to that which has completely protected (lab) animalsfrom Ebola," said Dr. Anthony Fauci, director of the NationalInstitute of Allergy and Infectious Diseases (NIAID), which isconducting the trial in Bethesda, Maryland.
The intramuscular vaccine was developed at NIAID andOkairos, a biotechnology company acquired by GlaxoSmithKline. Itcontains genetic material from two Ebola strains - Zaire,responsible for the current outbreak in West Africa, and Sudan -but no virus, so it cannot cause the disease.
Because it is unethical to expose volunteers to Ebola,researchers assess the effectiveness of candidate vaccines bywhether they trigger production of anti-Ebola antibodies andimmune-system T cells.
The trial enrolled volunteers ages 18 to 50. Half received alower dose and half a higher dose. All 20 developed anti-Ebolaantibodies within four weeks, with those on the higher doseproducing more.
Dose also affected production of T cells; seven of 10 peopleon the high dose produced one crucial kind of T cell, but onlytwo on the low dose did. The higher the dose required to triggerimmunity, the more challenging and expensive it will be toproduce large quantities of vaccine, manufacturers say.
Dr. Daniel Bausch of Tulane University, who wrote anaccompanying commentary, called the results promising butcautioned that there are many more challenges ahead before thevaccine's safety and efficacy are established.
Another GlaxoSmithKline vaccine, against the Zaire strain,is undergoing safety trials in England, Mali and Switzerland,while one from Iowa-based NewLink Genetics is beingtested in Maryland. This week, Merck announced that itwould buy the rights to NewLink's vaccine for $50 million. A trial of an Ebola vaccine from Johnson &Johnson is scheduled to start in January. (Reporting by Sharon Begley; Editing by Jonathan Oatis)
