Health and Healthcare

Big Step Forward in HER2-Positive Breast Cancer Trial

Chris Lange

Published: October 21, 2019 10:50 am

Last Updated: January 30, 2020 2:21 pm

Seattle Genetics Inc. (NASDAQ: SGEN) shares jumped on Monday after the firm announced positive results from its midstage breast cancer trial. Specifically, Seattle Genetics announced positive topline results from the HER2CLIMB trial, an active comparator pivotal trial evaluating tucatinib.

The trial compared tucatinib in combination with trastuzumab and capecitabine to trastuzumab and capecitabine alone in patients with locally advanced unresectable or metastatic HER2-positive breast cancer. Patients had previously received trastuzumab, pertuzumab and ado-trastuzumab emtansine (T-DM1), and 47% of the patients enrolled in the trial had brain metastases at the time of enrollment.

The trial met the primary endpoint of progression-free survival, showing that the addition of tucatinib was superior to trastuzumab and capecitabine alone, with a 46% reduction in the risk of disease progression or death. The trial also met the two key secondary endpoints at interim analysis. The tucatinib arm demonstrated an improvement in overall survival, with a 34% reduction in the risk of death compared to trastuzumab and capecitabine alone.

For patients with brain metastases at baseline, the tucatinib arm also demonstrated superior progression-free survival, with a 52% reduction in the risk of disease progression or death compared to those who received trastuzumab and capecitabine alone.

Roger Dansey, M.D., chief medical officer at Seattle Genetics, commented:

There is significant unmet medical need following treatment with trastuzumab, pertuzumab and T-DM1 in patients with metastatic HER2-positive breast cancer. The addition of tucatinib to the commonly used doublet of trastuzumab and capecitabine represents a potential significant clinical advance for patients with metastatic HER2-positive breast cancer, importantly, including those with brain metastases. Based on these findings, we plan to unblind the trial and offer tucatinib to patients on the control arm. We also plan to submit a New Drug Application (NDA) to the FDA in the first quarter of 2020, with the goal of bringing a much-needed new medicine to patients.

Shares of Seattle Genetics traded up about 16% to $101.18 on Monday, in a 52-week range of $50.71 to $101.40. The consensus price target is $87.29.