Priority Review of Seagen’s Colorectal Cancer Treatment Wins FDA Acceptance

On September 19, Seagen announced that the United States Food and Drug Administration (FDA) accepted the supplemental New Drug Application (sNDA) for Priority Review, seeking the approval of TUKYSA® (tucatinib). TUKYSA treats adult patients with HER2-positive colorectal cancer. The basis of Seagen’s application is the positive results of the phase 2 MOUNTAINEER trial. 

Related Article: AstraZeneca and Merck’s HER2-negative Breast Cancer Treatment Wins Yet Another Approval

How TUKYSA treats colorectal cancer?

Colorectal cancer is a group including colon and rectal cancers, depending on where the cancer begins. Both types of cancers share similarities, warranting their grouping. Most of these types of cancer form in the inner lining of the rectum or colon, eventually entering into the bloodstream and spreading to other parts of the body.

The American Cancer Society estimates around 151,000 new cases will be diagnosed in 2022 in the United States Alone. Of that total, 3.5% of patients’ cancer will overexpress Human epidermal growth factor receptor 2 (HER2). HER2 is an oncogenic driver used as a well-established therapeutic target in breast and gastric cancers. Treatments like Enhertu attach to the driver for the delivery of the treatment. 

TUKYSA inhibits the HER2 protein, resulting in a reduction of cell growth. In lab studies, TUKYSA showed significant inhibition of the growth of HER2-expressing tumors in combination with the anti-HER2 antibody trastuzumab. 

Originally approved by the FDA in 2020 for treating advanced, unresectable, or metastatic HER2-Positive Breast Cancer, Seagen now seeks approval for the treatment of HER2-Positive Metastatic Colorectal Cancer.

MOUNTAINEER Trial Wins FDA Acceptance

MOUNTAINEER is a Phase 2 trial of TUKYSA in combination with trastuzumab or as a single treatment. The study enrolled one-hundred-seventeen patients with HER2-positive unresectable or metastatic colorectal cancer following previous standard-of-care therapies. The trial’s primary endpoint is a confirmed objective response rate by RECIST (Response Evaluation Criteria in Solid Tumors). 

The trial’s results won over the FDA in granting Priority Review for TUKYSA’s sNBA. The FDA grants Priority Reviews to medicines that have the potential to provide significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of serious diseases.

On the acceptance, Marjorie Green, M.D., Senior Vice President and Head of Late-Stage Development at Seagen, said, “The FDA’s prioritization of our application for tucatinib in combination with trastuzumab supports our belief in its significant potential to benefit people with previously treated HER2-positive metastatic colorectal cancer.

The FDA set an action date of January 19, 2023, for their decision on the approval of TUKYSA as a colorectal cancer treatment.

Author

Max Heirich