When cancer cells learn to survive a drug designed to stop them, where do you turn next? A new study points to an unexpected possibility: a medicine used to treat parasitic worms.

Researchers combined the deworming medicine with a targeted lung cancer drug. In laboratory experiments, the pairing reduced resistant cancer-cell viability. In mice, tumors took longer to double in size with the combination than with either drug alone.

The idea was to find a weakness in cells that had learned to withstand treatment, then put that weakness under pressure.