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FDA Approves Tukysa for HER2-Positive Breast Cancer Maintenance
Confirmed
In Short: The FDA has approved Pfizer's Tukysa in combination with trastuzumab and pertuzumab as maintenance treatment for HER2-positive metastatic breast cancer.
The FDA has approved Pfizer's Tukysa (tucatinib) in combination with trastuzumab and pertuzumab as maintenance treatment for adults with unresectable locally advanced or metastatic HER2-positive breast cancer who have completed induction therapy, the company announced on October 7.
Tukysa, an oral therapy, is now being used in the first-line setting, where it is added to an established antibody pair. This approval moves the drug from later-line use into the front-line setting.
Aamir Malik, executive vice president and chief U.S. commercial officer of Pfizer, said, “Today's FDA approval marks the next chapter for Tukysa, bringing it into the front-line maintenance setting and offering patients a chemotherapy-free option that can help delay disease progression after initial treatment.”
The approval was based on the HER2CLIMB-05 trial, which included 654 patients with HER2-positive metastatic breast cancer with or without brain metastases. Eligibility criteria included having no evidence of progression after induction treatment with four to eight cycles of trastuzumab, pertuzumab, and a taxane.
The HER2CLIMB-05 trial showed that median investigator-assessed progression-free survival (PFS) was significantly improved with the addition of tucatinib to trastuzumab and pertuzumab, corresponding to a 35.9% reduction in the risk of progression or death.
Jennifer Taylor, founder and creative director of A Taylored Affair, a New York-based event planning and design company, has undergone treatment that includes 12 weeks of initial chemotherapy, a double mastectomy, 20 rounds of radiation, chemically induced menopause, and an additional chemotherapy treatment called ENHERTU.
Taylor said, “I had spent the first days after my diagnosis desperately searching the internet for someone who looked like me and whose life still looked vaguely recognizable. I wanted to know what chemo actually looked like. I wanted to know if I would ever laugh or go to dinner or wear something I liked or feel like myself again.”
The standard approach for advanced or metastatic HER2-positive disease has been upfront chemotherapy along with trastuzumab and pertuzumab, both HER2-targeted monoclonal antibodies, followed by maintenance with both antibodies until progression.
HER2 is overexpressed in up to 15% to 20% of breast cancers and is associated with poor prognosis. Pfizer cites an estimated five-year survival of 41% to 47%, depending on hormone receptor status.
Serious hepatotoxicity occurred in 3.9% of patients, including one fatal case of drug-induced liver injury, and hepatotoxicity led to discontinuation in 8%. The label carries a boxed warning for severe hepatotoxicity and calls for liver function testing before and during treatment.
Overall, 42% of tucatinib patients had grade ≥ 3 adverse events compared with 24% of patients in the placebo arm; 13% of tucatinib subjects stopped treatment due to adverse events, most commonly hepatic side effects.
Cardiac metastases are found in up to 18% of autopsies, but these metastatic tumors are often small, incidental, and asymptomatic.
What this adds
HER2 is overexpressed in up to 15% to 20% of breast cancers, and the five-year survival rate is estimated to be 41% to 47%, depending on hormone receptor status.
The standard approach for advanced or metastatic HER2-positive disease includes upfront chemotherapy with trastuzumab and pertuzumab, followed by maintenance with both antibodies until progression.
Background
The FDA has approved Pfizer's Tukysa in combination with trastuzumab and pertuzumab as maintenance treatment for HER2-positive metastatic breast cancer.
The FDA has approved pirtobrutinib (Jaypirca) for adults with previously untreated chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) without 17p deletion.
What's confirmed
- The FDA has approved Pfizer’s Tukysa (tucatinib) in combination with trastuzumab and pertuzumab as maintenance treatment for adults with unresectable locally advanced or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer who have completed induction therapy, the company announced Oct. 7. 1 The decision moves the oral therapy from later-line use into the first-line setting, where it is added to an established antibody pair.
What's still developing
- A recent Science study offers a possible explanation.
- Lung cancer cells grew rapidly in a mechanically unloaded transplanted heart but far less in the same mouse's native heart.
- In mice with cancer-driving mutations, tumors formed in the liver and skeletal muscle but not the heart.
- The heart is among the organs least likely to develop cancer, a long-standing biological puzzle.
- That approval was based on the 612-patient HER2CLIMB trial. 4 Pfizer describes the drug as a National Comprehensive Cancer Network Category 1 option for second-line and later use and reports five approved breast cancer medicines and one biosimilar. 1 Pfizer said safety was generally consistent with the known profile of Tukysa, except for increased severity of hepatotoxicity.
- 1 The results were published in the Journal of Clinical Oncology and presented at the 2025 San Antonio Breast Cancer Symposium.
- Jennifer Taylor and Adrien Finkel have been close since they were 2 years old A woman’s best friend since childhood is helping her navigate her breast cancer diagnosis.
- In May, the Food and Drug Administration (FDA) approved Datroway (datopotamab deruxtecan) as a new option for previously untreated patients with inoperable or metastatic triple-negative breast cancer (TNBC) who are not candidates for checkpoint inhibitor immunotherapy.
- “For patients with metastatic TNBC, a new first-line treatment option offers optimism to a community with historically few choices,” says Ricki Fairley, cofounder and CEO of TOUCH, the Black Breast Cancer Alliance.
- In June, the federal agency gave the nod to another TROP-2 ADC, Trodelvy (sacituzumab govitecan), as an initial treatment option for people with advanced TNBC.
- It is now approved for use before surgery (neoadjuvant therapy) and after surgery (adjuvant therapy) for patients with potentially curable cancer.
- A roundup of new options recently approved by the Food and Drug Administration.