Nicholas Fleming is optimistic his research will result in many more patients benefiting from the new drugs, including Keytruda.
"I’m feeling very positive," Dr Fleming, of the University of Otago pathology department, said.
He points out that a new class of drugs — called immune checkpoint inhibitors (ICIs) — is already "transforming" cancer treatment.
Such drugs were effective for about 20% of patients, who had "hypermutation" states in their cancers.
However, a series of research strategies which he is pursuing simultaneously, and which are backed by the Health Research Council, could make a big difference.
He has already pinpointed two key biomarkers to help identify who would benefit most from the new treatment, and has also found another drug "candidate" to be taken with ICIs to improve overall outcomes.
These moves could help extend the potential reach of the new drugs to 40% of patients within about four years, he said.
Bowel, or colorectal, cancer is New Zealand’s most commonly diagnosed cancer and, behind lung cancer, is the second most common cause of cancer death.
Otago, Southland and South Canterbury have particularly high incidence rates, being up to 20% above the national average.
Treatment was traditionally a mix of surgery and chemotherapy, and sometimes radiotherapy, but 40% of patients still died from the disease.
Such treatments had not significantly changed for more than 20 years, but the new ICI drugs were already "transforming" treatment.
These drugs could "dramatically reduce the size of tumours" and double the time before any disease recurrence.
Through research with the Southern District Health Board, 198 bowel cancer patients treated through Dunedin Hospital had undergone targeted genomic testing — also under way with another 100 patients.
This research had provided "an unprecedented view" of the cancer’s molecular nature, and highlighted groups of patients likely to benefit from treatment.
Cancer Society Otago and Southland Division acting chief executive Bob King praised Dr Fleming’s "great" efforts to better target and extend the range of new drug treatments.
Dr Fleming has also developed a new ICI combination treatment, including the use of another drug, that overall could "save more lives both here in the South and around the world".
