The late-stage trial evaluated patients with unresectable locally advanced or metastatic HER2-positive breast cancer and had previously received therapy with a taxane and trastuzumab
Seagen’s Tukysa shows positive results in late-stage trial. (Credit: Towfiqu barbhuiya on Unsplash)
Seagen has announced that its Tukysa (tucatinib) in combination with the ado-trastuzumab emtansine (Kadcyla) met its primary endpoint of progression-free survival (PFS) in Phase 3 HER2CLIMB-02 clinical trial of breast cancer patients.
Tukysa is an oral medicine that is a tyrosine kinase inhibitor of the human epidermal growth factor receptor 2 (HER2) protein.
The late-stage trial evaluated patients with unresectable locally advanced or metastatic HER2-positive breast cancer who had previously received therapy with a taxane and trastuzumab.
According to the company, the data on overall survival (OS), a secondary endpoint, are not yet mature.
In the combination arm of the experiment, discontinuations owing to adverse events were more frequent, but no new safety signals for the combination emerged.
Seagen chief medical officer and research and development president Roger Dansey said: “We are encouraged by these results for Tukysa in combination with Kadcyla in metastatic HER2-positive breast cancer, including in patients with brain metastases.
“We plan to present the HER2CLIMB-02 data at an upcoming medical meeting and discuss the results with the FDA.”
HER2CLIMB-02 is a global, multicentre, randomised, double-blind, placebo-controlled, Phase 3 clinical trial of Tukysa in combination with Kadcyla. The study initiated the enrolment in 2019.
The primary endpoint of the trial was defined as the PFS per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 by investigator assessment.
The key secondary endpoints included OS, PFS by blinded independent committee review (BICR), objective response rate, duration of response, PFS and OS in patients with brain metastases at baseline.
Tukysa is currently approved in the US in combination with trastuzumab and capecitabine for the same patient indication. Additionally, it is authorised in more than 40 nations.
The sole rights to market Tukysa outside of the US, Canada, and Europe belong to Merck, also known as MSD outside of those countries.
In March this year, Seagen was acquired by American pharmaceutical major Pfizer in an all-cash deal worth $43bn.