Relapse and mortality risk reduced by 53% compared to standard of care; 3-year disease-free survival rate reaches 92.4%
Indication expands from metastatic cancer to post-surgical adjuvant therapy; SC formulation currently in Phase 1 trials
Daiichi Sankyo and AstraZeneca’s antibody-drug conjugate (ADC) anti-cancer drug Enhertu has been approved in the European Union as a treatment for early breast cancer. With its application expanding from metastatic cancer to post-surgical adjuvant therapy aimed at preventing recurrence, the long-term commercialization prospects for the subcutaneous (SC) formulation—licensed out by Alteogen (196170)—have also broadened.
Daiichi Sankyo announced on the 27th that the European Commission (EC) has approved Enhertu as a post-surgical adjuvant therapy for adult patients with HER2-positive early breast cancer. The approval targets patients who have residual invasive cancer after receiving pre-surgical (neoadjuvant) taxane-based chemotherapy and HER2-targeted therapy.
This approval marks Enhertu’s entry into the treatment of early breast cancer in the EU with a curative intent. While previously used primarily for unresectable or metastatic cancers, the therapy can now be prescribed to prevent recurrence in patients who have undergone surgery.
The approval was based on the global Phase 3 clinical trial 'DESTINY-Breast05,' which involved 1,635 patients. The Enhertu arm demonstrated a 53% reduction in the risk of invasive disease recurrence or death compared to the current standard of care, trastuzumab emtansine (T-DM1) (HR=0.47).
The 3-year invasive disease-free survival (IDFS) rate was 92.4% for Enhertu compared to 83.7% for T-DM1, marking an 8.7 percentage point difference. The safety profile was largely consistent with previously known data, with no new safety concerns identified.
Enhertu was approved in the EU in June as a treatment for HER2-positive metastatic solid tumors, followed by an approval in September as a first-line treatment for HER2-positive metastatic breast cancer. With this latest approval in early breast cancer, the drug has expanded its indications three times over the past four months.
In November 2024, Alteogen entered into an exclusive licensing agreement with Daiichi Sankyo for the development and commercialization of an SC formulation of Enhertu. The deal is valued at up to $300 million, excluding commercial sales royalties.
The SC formulation of Enhertu, utilizing Alteogen’s 'ALT-B4' technology, is currently in Phase 1 clinical development. The trial is evaluating the safety and pharmacokinetic properties of the treatment in patients with recurrent or metastatic solid tumors.
Early breast cancer treatment requires repeated administration of anti-cancer drugs over a set period to prevent post-surgical recurrence. If an SC formulation is successfully developed to reduce administration time compared to intravenous (IV) infusions, it could significantly enhance patient convenience and medical institution efficiency.
The ongoing SC clinical trials are not currently focused on early breast cancer patients. Furthermore, this EU approval applies to the existing intravenous formulation and does not directly translate to immediate additional revenue for Alteogen. However, depending on future clinical development and regulatory expansions of the SC formulation, early breast cancer could emerge as a new commercial target.
