Ionis is up more than 8% after its shares rallied amid President Rodrigo Duterte’s crackdown on illegal drugs.
The Philippines has been plagued by an opioid epidemic, which has killed more than 1,200 people.
Duterte has called on drug users to go to rehab to help them quit the drug trade.
The stock rose more than 15% in after-hours trading on Tuesday.
The company had a price-to-earnings ratio of 13.4% in 2016, according to FactSet data.