FDA OKs New Treatment for Advanced or Metastatic HER2-Positive Breast Cancer

Officials with the FDA today approved tucatinib (Tukysa, Seattle Genetics) in combination with chemotherapy trastuzumab and capecitabine for the treatment of adults with advanced forms of HER2-positive breast cancer, according to a press release.^1,2

This is the first new drug approved as part of the agency’s Project Orbis, which is a partnership between the FDA, Health Sciences Authority (HSA), and Swissmedic. This approval was based on a collaborative review effort between the agency and the Australian Therapeutic Goods Administration, Health Canada, HSA, and Swissmedic.¹

Tucatinib, an oral, small molecule tyrosine kinase kinase inhibitor, is approved for treatment after patients have taken 1 or more anti-HER2-based regimens in the metastatic setting.¹

This approval was based on data from the HER2CLIMB clinical trial involving 612 patients who had HER2-positive advanced unresectable or metastatic breast cancer and had prior treatment with trastuzumab, pertuzumab, and ado-trastuzumab emtansine (T-DM1). The primary endpoint of the study was progression-free survival (PFS), with overall survival (OS) and PFS in patients with brain metastases at baseline as key secondary endpoints.²

Overall, the median PFS in patients who received tucatinib, trastuzumab, and capecitabine was 7.8 months compared with 5.6 months in those patients who received placebo, trastuzumab, and capecitabine.²

The median OS in patients who received tucatinib, trastuzumab, and capecitabine was 21.9 months compared with 17.4 months in patients who received placebo, trastuzumab, and capecitabine, according to the data. Median PFS in patients with brain metastases at baseline who received tucatinib, trastuzumab, and capecitabine was 7.6 months compared with 5.4 months in patients who received placebo, trastuzumab, and capecitabine.²

Common adverse effects (AEs) for patients taking tucatinib were diarrhea, palmar-plantar, erythrodysesthesia, nausea, fatigue, hepatotoxicity, vomiting, stomatitis, decreased appetite, abdominal pain, headache, anemia, and rash.¹

Serious AEs occurred in 26% of patients who received tucatinib. Serious adverse reactions occurring in 2% or more of patients who received tucatinib were diarrhea, vomiting, nausea, abdominal pain, and seizure.

“We recognize that patients with cancer constitute a vulnerable population at risk of contracting the coronavirus disease,” Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the FDA’s Center for Drug Evaluation and Research, said in a statement.¹ “This approval represents an additional targeted treatment option for patients with HER-2 positive breast cancer. The clinical trial supporting this approval enrolled and specifically studied patients with active brain metastases in addition the overall population enrolled, which also demonstrated benefit in this subgroup.”

References:

1. FDA Approves First New Drug Under International Collaboration, A Treatment Option for Patients with HER2-Positive Metastatic Breast Cancer. News Release. FDA; April 17, 2020. Accessed April 17, 2020. https://www.fda.gov/news-events/press-announcements/fda-approves-first-new-drug-under-international-collaboration-treatment-option-patients-her2.

2.  Seattle Genetics Announces US FDA Approval of Tukysa (tucatinib) for People with Advanced Unresectable or Metastatic HER2-Positive Breast Cancer. News Release. Seattle Genetics; April 17, 2020. Accessed April 17, 2020. https://investor.seattlegenetics.com/press-releases/news-details/2020/Seattle-Genetics-Announces-US-FDA-Approval-of-TUKYSA-tucatinib-for-People-with-Advanced-Unresectable-or-Metastatic-HER2-Positive-Breast-Cancer/default.aspx.