The contract manufacturing firm said hopes to raise approximately $625m (€566m). It also revealed that it generated revenue of $1.8bn and net income of $9.7m in the past 12 months.
Originally, the firm said that listing would generate $100m.
The move follows a few years after CMO sector rival Catalent went public.
Patheon employs about 8,700 worldwide, including 5,100 employees in North America, 3,525 in Europe and 75 in the Asia-Pacific region.
The firm claims to work with 18 of the 20 largest pharmaceutical companies.
This includes Amgen with which it agreed a strategic partnership in March. At the time Patheon said most of the Amgen work will be conducted at its facility Monza, Italy site which offers pre-filled syringes, sterile liquid, lyophilization and solid dose manufacturing.
In the S1 filed last June, Patheon revealed that a significant portion of our revenues comes from a limited number of customers.
"For the year ended October 31, 2014, our top 10 customers and products accounted for 39% and 24%, respectively, of our revenues. No customer accounted for more than 7% of our revenue for the year ended October 31, 2014."
Patheon expanded its active pharmaceutical ingredients (API) business last year when it acquired hard-to-make API specialist Irix Pharmaceuticals.
The deal saw Patheon add Irix's small-scale manufacturing facility in Florence, South Carolina and large scale production site in neighbouring Greenville to its network.
Patheon’s debt is worth noting. According to the S1, the firm has debts of $1.95bn partly due to a number of recent acquisitions.
In addition to Irix, in the past four years Patheon has bought capsule maker Banner Pharmacaps for $255m; biologics contractor Gallus BioPharmaceuticals in 2014 and bioavailability enhancement specialist Agere Pharmaceuticals in 2015.
The firm said it will use some of the funds generated through the IPO to pay its debts.