Zai Lab Limited announced the phase 3 METIS clinical trial met its primary endpoint, demonstrating a statistically significant improvement in time to intracranial progression for adult patients treated with Tumor Treating Fields (TTFields) therapy and supportive care compared to supportive care alone in the treatment of patients with 1-10 brain metastases from non-small cell lung cancer (NSCLC) following stereotactic radiosurgery (SRS). Patients treated with TTFields therapy and supportive care exhibited a median time to intracranial progression of 21.9 months compared to 11.3 months in patients treated with supportive care alone for brain metastasis (n=298; hazard ratio=0.67; P=0.016). Median TTFields therapy treatment duration was 16 weeks and median usage was 67%.

Consistent with previous studies, TTFields therapy was well-tolerated with sustained quality of life and neurocognitive function. Baseline characteristics were well balanced between arms. Preliminary analyses of key secondary endpoints (time to neurocognitive failure, overall survival, and radiological response rate) did not demonstrate statistical significance. Certain secondary endpoints showed positive trends in favor of treatment with TTFields therapy, including time to distant progression and quality of life.

Full analysis of secondary endpoints is ongoing. Novocure intends to submit these data to regulatory authorities. Novocure also intends to publish these findings in a peer-reviewed scientific journal and share them at an upcoming scientific congress.

Zai Lab contributed to the METIS trial and achieved treatment of the first patient in Greater China in May 2021. METIS [NCT02831959] is a phase 3 trial of stereotactic radiosurgery with or without TTFields therapy for patients with 1-10 brain metastases from NSCLC. 298 adult patients were enrolled in the trial and randomized to receive either TTFields therapy with supportive care or supportive care alone following SRS.

Supportive care consisted of, but was not limited to, treatment with steroids, anti-epileptic drugs, anticoagulants, pain control or nausea control medications. Patients in both arms of the study were eligible to receive systemic therapy for their NSCLC at the discretion of their treating physician. Patients with known tumor mutations for which targeted agents are available were excluded from the trial.

The primary endpoint of the METIS trial is time to first intracranial progression, as measured from the date of first SRS treatment to intracranial progression or neurological death (per RANO-BM criteria), whichever occurs first. Time to intracranial progression was calculated according to the cumulative incident function. Patient scans were evaluated by a blinded, independent radiologic review committee.

Secondary endpoints include, but are not limited to, time to distant progression, time to neurocognitive failure, overall survival, time to second intracranial progression, quality of life and adverse events. Key secondary endpoints (time to neurocognitive failure, overall survival, and radiological response rate) were planned to be used in labeling claims, if successful. Patients were stratified by the number of brain metastases (1-4 or 5-10 metastases), prior systemic therapy, and tumor histology.

Patients were allowed to crossover to the experimental TTFields therapy arm following confirmation of second intracranial progression. Brain metastases are secondary tumors formed when cancer cells break away from the primary tumor and travel through the blood or lymph system to form new tumors (or metastases) in the brain. Brain metastases are a negative prognostic factor in NSCLC and adversely impact neurocognitive function and quality of life.

Each year in China, approximately 740,000 patients are newly diagnosed with NSCLC. Approximately 20%?65% of lung cancer patients develop brain metastases at some point during their illness.1 Among patients who received chemotherapy, the survival of patients with brain metastases at diagnosis was still poor, which is about six months. Treatment options for patients with brain metastases from NSCLC are limited to neurosurgery, SRS, whole brain radiation therapy, or combinations of these options.

However, given the neurotoxicity and significant decline in cognitive functioning, whole brain radiation therapy (WBRT) is an unfavorable treatment option. New therapeutic options are needed for greater intracranial control while minimizing the risk of neurocognitive adverse events.