ArriVent BioPharma said a treatment it's developing for a type of lung cancer failed to meet the primary endpoint in a Phase 3 trial.

The stock slid 59% to $11.77 in premarket trading on Tuesday. At Monday's market close, shares were up 41% year to date.

The biopharmaceutical company on Tuesday said its firmonertinib monotherapy didn't show a meaningful improvement in progression-free survival over chemotherapy in certain patients with previously untreated, locally advanced or metastatic non-squamous non-small cell lung cancer.

"These disappointing results are not what we hoped for," Chief Executive Bing Yao said.

Yao said the company is evaluating the full dataset from the trial as it works to decide on the appropriate development path for firmonertinib.

ArriVent said the drug's safety profile in the study was consistent with previous clinical studies.