Zymeworks halts development of cancer drug after trial setback

Zymeworks ZYME said on Tuesday it will stop developing its experimental cancer drug after results from an early-stage trial showed the treatment was unlikely to benefit as a standalone therapy.

The Vancouver-based company was testing the drug, ZW171, in patients with ovarian and non-small cell lung cancers, aiming to enroll about 160 participants.

"This is a disappointing outcome given the promising preclinical activity observed with ZW171," said chief executive Kenneth Galbraith.

The drug was designed to target mesothelin, a protein found on the surface of healthy cells as well as at abnormal levels on some cancer cells, including those affecting the lungs, ovaries, and digestive system.

While Zymeworks identified a maximum tolerated dose of ZW171 in the study, it affected healthy cells that naturally have this protein. The company said continuing the study would not support a strong enough benefit-risk profile for the drug as a monotherapy.

Patients who were enrolled in the study may continue receiving the drug if their doctors recommend it, Zymeworks said, adding that those who have stopped treatment would be monitored for safety.

There are currently no approved treatments that specifically target mesothelin, but companies including China-based RemeGen 688331 and Bayer BAYN are testing their experimental therapies.