In 2015, one billion people worldwide were treated for at least one tropical disease. Companies have donated seven billion treatments since 2012.
The World Health Organisation said improving water and sanitation was key to driving further progress.
Some 170,000 people die from one of the illnesses every year, but their biggest impact is disabling their sufferers.
In an interview with BBC News, Bill Gates praised pharmaceutical companies for "doing their part in a great relationship" by donating treatment at "a phenomenal scale".
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