A biotech start-up backed by some of Australia's most prominent businessmen has won a US grant that will be used to run clinical trials for a drug candidate aiming to help curb the opioid crisis gripping the nation.

The family offices of ex-Macquarie big wigs Allan Moss and Michael Carapiet, former Toll Holdings CEO Paul Little and AustralianSuper director Jim Craig are among the 20-odd investors in Kinoxis Therapeutics – which is hopeful of developing pharmaceuticals to manage cravings for drugs through management of the brain’s oxytocin system.