The trial is set to start on November 30.
He is accused of multiple counts of murder and attempted murder in connection with his country's "war on drugs".
The campaign began in the city of Davao, where Duterte served as mayor, before he expanded it across the country during his presidency from 2016 to 2022.
Death squads were deployed, killing not only dealers and drug producers but also addicts.
Human rights organisations estimate that 30,000 people were killed.
Suspects are said to have often been summarily executed without trial.
The former president was arrested in Manila in March 2025 based on an ICC arrest warrant and flown to the Netherlands.
He has denied all charges.
Duterte had failed to appear at several hearings, with his defence lawyers citing health reasons.
He appeared before the judges for the first time at a hearing in September.
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