FDA Approves ENHERTU Plus Pertuzumab as First New First-Line Treatment for HER2-Positive Metastatic Breast Cancer in a Decade
核心洞察
The FDA has approved ENHERTU (fam-trastuzumab deruxtecan-nxki) plus pertuzumab as the first new first-line treatment for HER2-positive metastatic breast cancer (搜索) in over a decade.
The approval is based on results from the DESTINY-Breast09 Phase III trial, which demonstrated superior efficacy compared to the standard taxane, trastuzumab, and pertuzumab (THP) regimen.
This represents a significant advancement for approximately 10,000 patients treated annually in the first-line HER2 (搜索)-positive metastatic setting in the US.
The FDA has approved ENHERTU (fam-trastuzumab deruxtecan-nxki) at 5.4 mg/kg in combination with pertuzumab as a first-line treatment for adult patients with unresectable or metastatic HER2 (搜索)-positive breast cancer (搜索). This marks the first new treatment option in this setting in more than a decade, representing a significant milestone for patients facing this aggressive disease.
The approval is based on results from DESTINY-Breast09, a global, multicenter, randomized, open-label Phase III trial that evaluated ENHERTU either alone or in combination with pertuzumab versus the standard of care taxane, trastuzumab, and pertuzumab (THP) regimen. The study enrolled 1,157 patients across multiple sites in Africa, Asia, Europe, North America, and South America.
Addressing Critical Unmet Medical Need
HER2-positive metastatic breast cancer (搜索) affects approximately one in five breast cancer (搜索) cases and represents an aggressive disease driven by overexpression or amplification of HER2 (搜索). Despite advances in HER2-targeted therapies, prognosis remains poor, with most patients experiencing disease progression within two years of first-line treatment with THP, which has been the standard of care for more than a decade.
The clinical need for new treatment options is underscored by sobering statistics: approximately 25% to 30% of patients do not receive any treatment following first-line therapy due to discontinuation or death. With approximately 10,000 patients treated each year in the first-line HER2 (搜索)-positive metastatic setting in the US, this approval addresses a significant gap in care.
DESTINY-Breast09 Trial Design and Results
DESTINY-Breast09 was designed as a three-arm study where patients were randomized 1:1:1 to receive either ENHERTU monotherapy with a pertuzumab matching placebo, ENHERTU in combination with pertuzumab, or THP. Randomization was stratified by prior treatment, hormone receptor status, and PIK3CA mutation status.
The primary endpoint was progression-free survival (PFS) as assessed by blinded independent central review in both the ENHERTU monotherapy and ENHERTU combination arms. Secondary endpoints included investigator-assessed PFS, overall survival, objective response rate, duration of response, pharmacokinetics, and safety.
Safety Profile and Management
The safety profile of ENHERTU in combination with pertuzumab was evaluated in 431 patients from the pooled DESTINY-Breast07 and DESTINY-Breast09 studies. Among these patients, 86% were exposed for more than six months and 73% for more than one year.
The most common adverse reactions (≥20%) included decreased white blood cell count (86%), decreased hemoglobin (80%), decreased neutrophil count (79%), nausea (74%), increased alanine aminotransferase (65%), diarrhea (64%), and increased aspartate aminotransferase (63%).
Serious adverse reactions occurred in 27% of patients receiving the combination. The most frequent serious adverse reactions included diarrhea, pneumonia, febrile neutropenia (搜索), hypokalemia, vomiting, interstitial lung disease (搜索) (ILD), pulmonary embolism, and sepsis. Fatalities due to adverse reactions occurred in 3.4% of patients.
Key Safety Considerations
Healthcare providers must monitor for several important safety concerns. ILD occurred in 12% of patients treated with ENHERTU 5.4 mg/kg in combination with pertuzumab, with a median time to first onset of 8.0 months. Fatal outcomes due to ILD and/or pneumonitis (搜索) occurred in 0.5% of patients.
Neutropenia (搜索) represents another significant concern, with decreased neutrophil count occurring in 79% of patients receiving the combination therapy. Twenty-nine percent experienced Grade 3 or 4 decreased neutrophil count, and febrile neutropenia was reported in 2.6% of patients.
Left ventricular dysfunction was observed in 11% of patients treated with the combination, with 2.1% experiencing Grade 3 or 4 events. Regular monitoring of left ventricular ejection fraction is required throughout treatment.
Mechanism of Action and Development
ENHERTU is a HER2 (搜索)-directed antibody-drug conjugate (ADC) designed using Daiichi Sankyo's proprietary DXd ADC Technology. The drug consists of a HER2 monoclonal antibody attached to topoisomerase I (搜索) inhibitor payloads via tetrapeptide-based cleavable linkers.
This approval represents the culmination of a collaboration between AstraZeneca and Daiichi Sankyo, who entered into a global partnership to jointly develop and commercialize ENHERTU in March 2019. The comprehensive global clinical development program continues to evaluate ENHERTU as monotherapy, in combination, or sequentially with other cancer medicines across multiple HER2 (搜索)-targetable cancers.
Broader Impact on Breast Cancer Treatment
The approval of ENHERTU plus pertuzumab represents a paradigm shift in first-line treatment for HER2-positive metastatic breast cancer (搜索). With breast cancer (搜索) being the second most common cancer worldwide, affecting more than two million patients diagnosed in 2022, and with more than 300,000 cases diagnosed annually in the US, this advancement has significant implications for patient care.
While survival rates remain high for early-stage breast cancer (搜索), only about 30% of patients diagnosed with or who progress to metastatic disease are expected to live five years following diagnosis. This new treatment option offers hope for improved outcomes in this challenging patient population.
The investigational arm assessing ENHERTU monotherapy versus THP remains blinded and will continue to the final PFS analysis, potentially providing additional treatment options for patients in the future.