Seattle Genetics Enters Breast Cancer Market with Tukysa

By Ruchi Jhonsa, Ph.D.

Seattle Genetics has finally launched itself in the breast cancer market. On 17th April, the company announced FDA approval for Tukysa, a tyrosine kinase inhibitor of HER2, in combination with Roche’s trastuzumab and capecitabine for adult patients with advanced unresectable or metastatic HER2-positive breast cancer, including patients whose cancer has spread to the brain or have received one or more prior anti-HER2 based regimens in the metastatic setting. Previously the drug had gained breakthrough designation and priority review from the agency.

According to Eric P Winer, Chief of the Division of Breast Oncology, Susan F. Smith Center for Women’s Cancers at Dana-Farber “Cancer spreads to the brain in up to half of the patients with HER2-positive metastatic breast cancer; and this approval is based on a unique clinical trial that included patients with active brain metastases, either untreated or progressing. Tukysa is well tolerated by patients and is a valuable addition to the agents we have for HER2-positive metastatic breast cancer.”

The FDA approval for the drug was based on the results showing the efficacy of the drug in combination with trastuzumab, another HER2 inhibitor and capecitabine, an antimetabolite in improving progression-free survival (PFS), overall survival (OS), objective response rate, and safety. The drug was reviewed using the Real-Time Oncology Review (TROR), a pilot program where the FDA gets access to key data prior to official submission. This allows the review team to begin their review earlier and communicate with the sponsor prior to the application’s actual submission. “Tukysa was approved four months prior to FDA goal date, providing an example of this commitment and showing how our regular work in reviewing treatments for patients with cancer is moving forward without delay,” said Richard Pazdur, MD, Director of the FDA’s Oncology Center of Excellence and acting Director of the Office of Hematology and Oncology Products.

The company has set the price for the drug “in line with other recently approved novel cancer meds” at $18,500 for a 30-day supply with an average cost for a course at 111,000$ per patient.

Tukysa, a Valuable Addition to Breast Cancer Therapy

Tukysa inhibits cell growth by perturbing the functioning of MAPK and AKT signaling. On its own, Tukysa was able to inhibit the growth of HER2-expressing tumors but when combined with trastuzumab, it became much more effective in suppressing HER2 positive tumor growth.

The trial HER2CLIMB comprised of 612 patients with HER2 positive breast cancer that was difficult to remove surgically or had spread to the brain. However, the primary endpoint of progression-free survival was assessed only in the first 480 patients by blinded independent central review (BICR). The combination of tukysa with trastuzumab and capecitabine reduced the risk of cancer progression or death (PFS) by 46% when compared to trastuzumab and capecitabine alone. Additionally, the combo reduced the risk of death (OS) by 34 % and effectively increased the objective response rate (41%) as well as progression-free survival (52%) in patients with brain metastasis, making it the most “stunning” result of the trial. However, the drug had severe adverse reactions in 26 percent of patients, which included diarrhea, vomiting, nausea, abdominal pain and seizure.

“We’re pleased to have collaborated with the FDA on our second expedited real-time oncology review, enabling us to rapidly bring this new targeted medicine to patients,” said Clay Siegall, Ph.D., CEO at Seattle Genetics. “Tukysa has shown impressive results in people with HER2-positive metastatic breast cancer, including in patients with active brain metastases, and offers patients an effective medicine following previous treatment with other anti-HER2 agents in the metastatic setting.”

Related Article: NERLYNX-XELODA Combo Bags FDA Approval for HER2 Positive Breast Cancer Treatment

References

1. 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

Author

Ruchi Jhonsa