The device, currently an aid mobility for wheelchair users, is being assessed for its potential to help treat people with spinal cord injuries.
Feedback from the RAPPER II investigation found that 19 of the 20 volunteers were able to complete the walk exercise protocol – a 95% success rates.
There were no adverse events, Rex also reported.
RAPPER stands for robot-assisted physiotherapy exercises with REX.
And the trial assessed the safety and feasibility of a set of customised exercises using the state-of-the-art exoskeleton.
The data was presented by Dr Andrew Nunn of the Austin Health: Royal Talbot Rehabilitation Centre, Melbourne, Australia.
Chief executive Crispin Simon said: "I am delighted by these positive results. They are a strong message to those philanthropists who are considering donating a REX to their local rehabilitation centre; and to insurance and tax-funded healthcare systems.
"With the additional questionnaires and the seven day follow-up, positive results from the next interim analysis would confirm that REX is not just about standing and walking - great though that is - but also that there is also a therapeutic effect for people who live with spinal cord injury."
The next new RAPPER II sites will be the Royal National Orthopaedic Hospital NHS Trust, in Stanmore, on the outskirts of London and Austin Health: Royal Talbot Rehabilitation Centre, Melbourne, Australia.