Johnson & Johnson is third to bring Ebola vaccine to trials, but is it too late?

J&J R&D chief Paul Stoffels

Johnson & Johnson ($JNJ) started Phase I trials Tuesday for its Ebola vaccine, which its Janssen subsidiary developed in collaboration with Denmark's Bavarian Nordic. The jab is the third such vaccine to enter human trials, coming after GlaxoSmithKline's ($GSK) prospect and a candidate from Merck ($MRK) and NewLink ($NLNK), which are both in clinical development. So, does J&J's candidate come too late to catch up with its rivals and help combat the current epidemic?

J&J's chief scientific officer, Paul Stoffels, isn't worried about that.

"As long as there are still Ebola patients, there is the risk that it will continue to go around the region," he told reporters. "Does it come too late? … I don't think so."

Experts have projected demand for a preventive Ebola vaccine at anywhere between 100,000 doses--if only frontline workers are vaccinated--to 12 million doses, if large-scale adult vaccination in the affected countries is needed.

J&J announced that more than 400,000 vaccine regimens have been produced, to be used in large-scale clinical trials by April. It will make a total of 2 million regimens over the course of 2015, and it's able to ramp up production to 5 million over a period of 12 to 18 months if required, J&J's release said. The Oxford Vaccine Group, part of the University of Oxford Department of Pediatrics, is leading the current trial, which will involve 72 healthy adult volunteers.

Dr. Matthew Snape is leading the study.

"We've been working at an unprecedented pace together with our partners to significantly accelerate our efforts," said Dr. Matthew Snape of the Oxford Vaccine Group and the study leader. "Initiating this study in the space of 8 weeks represents a critical leap forward in being able to rapidly develop an Ebola prime-boost vaccine regimen, and these results will be vital to the design of future studies in broader populations."

And J&J's vaccine is unique among others in development: It's a two-dose, "prime-boost" vaccination regimen, meaning that a first dose is given to prime the immune system, and a booster is given later to enhance the immune response over time, Bavarian Nordic said in a statement. It can also be stored in a fridge for several months, instead of requiring special freezing, Reuters reports.

"What we are doing with prime-boost is going for maximal protection, as well as long-term protection," Stoffels told Reuters. Requiring two doses instead of one, however, may make mass immunization more complicated.

More trials are planned for the U.S. later this month and later on, in Africa.

- here's J&J's release
- and here's Bavarian Nordic's release
- get more from Reuters

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