Human rights activists had been hoping that leaders at the summit would raise the issue of the thousands of users and small-time pushers killed in the campaign that was launched by Duterte after he took office in mid-2016.
His government says the police act in self-defence during drug-busts, but critics say executions are taking place with no accountability.
There was no pressure from US President Donald Trump on the drugs war when he met Duterte on Monday and Trump later said the two had a "great relationship".
Duterte cursed Trump's predecessor, Barack Obama, last year for raising concerns about the war on drugs.
Trudeau also said that he raised the issue of the exodus of Rohingya during a meeting with Myanmar leader Aung San Suu Kyi, another sensitive topic bypassed by most other leaders, although he did not mention the Muslim minority by name.
"This is a tremendous concern to Canada and to many, many countries around the world," he said.
The government in mostly-Buddhist Myanmar regards the Rohingya as illegal immigrants from Bangladesh and does not recognise the term.
Over 600,000 Rohingya have fled to refugee camps in Bangladesh since military clearance operations were launched in response to attacks by Rohingya militants on August 25.
On other issues, Duterte reported that China had agreed at the summit to work on a code of conduct in the South China Sea, and the group also signed agreements on protecting migrant labour and fighting terrorism and cybercrime.
-AAP
