The NSW oncologist leading the world-first medicinal cannabis trial to treat patients suffering chemotherapy-induced nausea says it's "making good progress".
In operation since December at Chris O'Brien Lifehouse cancer hospital in Sydney's Camperdown and the regional Orange Health Service, the trial has now been expanded to include seven more hospitals across NSW.
Previously there's been little in the way of high-quality research internationally on the role of cannabis to treat nausea and vomiting caused by chemotherapy, says lead oncologist and Associate Professor Peter Grimison.
"The patients who have gone through so far haven't had any serious or unexpected side effects," Prof Grimison, from Chris O'Brien Lifehouse, told AAP.
The trial is "making good progress".
While the trial remains in its start-up phase, patient numbers are expected to rise from the hospital expansion.
Eligible patients at Campbelltown, Concord, Royal North Shore, Calvary Mater Newcastle, Coffs Harbour, Port Macquarie Base and Wollongong hospitals will now be able to take part, NSW Health Minister Brad Hazzard announced on Thursday.
The government has invested $21 million in medicinal cannabis research, with $1 million targeted at cultivation.
"The first part of the trial is to recruit 80 patients and we're hoping to reach that in the next 12 months," Prof Grimison.
The aim is to get up to 250 trial patients for its second phase over the next couple of years.
In the trial, patients take one capsule - containing plant-derived delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) - on the day before each round of chemotherapy, and every day for the next five days.
While THC "is the type of cannabis that can make people feel dizzy or disorientated or stoned", Prof Grimison says the addition of CBD "lessens the side effects" and helps with a patient's relaxation and anxiety.
He said "street cannabis" is almost all THC whereas the trial's has a lot less.
"We think that combination will actually be more effective in reducing nausea in chemotherapy."
Prof Grimison is hopeful of positive trial outcomes leading to more doctors prescribing medicinal cannabis, more patients coming on board and further funding.
Interested patients are encouraged to contact their cancer specialist or medical oncologist to discuss eligibility.
