Daiichi Sankyo’s Breast Cancer Treatment, Enhertu, Approved in Japan

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Daiichi Sankyo’s trastuzumab deruxtecan, marketed as Enhertu, has been approved in Japan for the treatment of adults with hormone receptor (HR) positive, HER2 low (IHC 1+ or IHC 2+/ISH-) or HER2 ultralow (IHC 0 with membrane staining) unresectable or recurrent breast cancer, the company announced in a press release on Aug. 25, 2025 (1).

Prevalence of breast cancer in Japan

According to Daiichi Sankyo, breast cancer is the most common cancer in women in Japan, with approximately 92,000 cases diagnosed in 2022, and approximately 17,600 deaths (1). HR positive, HER2 negative breast cancer, the most common breast cancer subtype, accounts for approximately 70% of those cancers.

“Enhertu continues to transform the way breast cancer is treated, becoming the first HER2 directed medicine approved in Japan for patients with HR positive, HER2 low or HER2 ultralow metastatic breast cancer,” said Yuki Abe, PhD, head of R&D Division in Japan and head of Research, Daiichi Sankyo, in a press release (1). “This approval, which is the fifth indication for Enhertu in Japan in five years, brings this important medicine to an earlier treatment setting and a broader patient population with lower levels of HER2 expression.”

Daiichi Sankyo, AstraZeneca treatments advancing

The approval of trastuzumab deruxtecan in Japan comes just one week after Daiichi Sankyo announced, on Aug. 18, 2025, that it had received breakthrough therapy designation from FDA for another cancer therapy, ifinatamab deruxtecan, to be used to treat adults with extensive-stage small cell lung cancer whose disease has progressed following platinum-based chemotherapy (2).

FDA had previously approved Enhertu (fam-trastuzumab deruxtecan-nxki), jointly developed for the US market by Daiichi Sankyo and AstraZeneca, in January 2025 in the same indications for which the treatment was green-lighted in Japan (3). That approval was featured by Pharmaceutical Technology® Group among the latest advances in the industry on World Cancer Day, on Feb. 4, 2025.

Another breast cancer treatment from AstraZeneca, Lynparza (olaparib), was accepted within NHS Scotland, that country’s healthcare system, by the Scottish Medicines Consortium in February 2025 (4). It is intended for treatment of adults with HER2-negative, locally advanced or metastatic breast cancer with germline breast cancer genes 1 or 2 mutations after chemotherapy.

Latest in breast cancer breakthroughs

Elsewhere in development of treatments related to breast cancer, part of the disclosure of a business combination agreement between Vesicor Therapeutics and Black Hawk Acquisition in April 2025 was a detailed update on Vesicor’s genetically engineered cellular microvesicle non-viral nanoparticle RNA vesicle, ecm-RV/p53, which patients with advanced breast, pancreatic, prostate, lung, and colorectal cancers have used, Vesicor said, and which has the potential to treat a range of solid tumors (5). Preclinical testing is expected to begin in the United States, with an investigational new drug application planned for submission to FDA in 2026.

A biosimilar developed by Celltrion for denosumab, Stoboclo (denosumab-bmwo), referencing Amgen’s Prolia, has been made commercially available in the US as of July 2025 (6). Stoboclo 60 mg/mL injection has been approved for indications including increasing bone mass in men with osteoporosis or who are receiving androgen deprivation therapy for nonmetastatic prostate cancer, or in women receiving adjuvant aromatase inhibitor therapy for breast cancer.

In June 2025, BioNTech and Bristol Myers Squibb entered a global co-development and co-commercialization agreement valued at up to $11.1 billion for BNT327, BioNTech’s investigational bispecific antibody targeting programmed death-ligand 1 and vascular endothelial growth factor A (7). BNT327 is currently being studied in more than 20 clinical trials, with a Phase III trial in triple-negative breast cancer scheduled to begin by the end of 2025.

References

1. Daiichi Sankyo. Enhertu Approved in Japan as First HER2 Directed Medicine for Patients with HER2 Low or HER2 Ultralow Metastatic Breast Cancer Following at Least One Endocrine Therapy. Press Release. Aug. 25, 2025.
2. Daiichi Sankyo. Ifinatamab Deruxtecan Granted Breakthrough Therapy Designation by US FDA for Patients with Pretreated Extensive-Stage Small Cell Lung Cancer. Press Release. Aug. 18, 2025.
3. AstraZeneca. Enhertu Approved in the US as First HER2-directed Therapy for Patients with HER2-low or HER2-ultralow Metastatic Breast Cancer Following Disease Progression After One or More Endocrine Therapies. Press Release. Jan. 27, 2025.
4. AstraZeneca. Lynparza (olaparib) Accepted for Use in Scotland to Treat Germline BRCA-Mutated HER2-Negative Locally Advanced or Metastatic Breast Cancer After Chemotherapy. Press Release. Feb. 10, 2025.
5. Haigney, S. Vesicor Therapeutics Enters into Business Agreement with Black Hawk to Advance Oncology Treatments. BioPharmInternational.com, April 29, 2025.
6. Lavery, P. Two Celltrion Denosumab Biosimilars Now Available in US. BioPharmInternational.com, July 8, 2025.
7. Cole, C. BioNTech to Receive Up to $11.1 Billion in Deal with BMS to Develop Immuno-Oncology Agent. BioPharmInternational.com, June 2, 2025.