[Edaily Reporter KIM SAE-MI ] Alteogen Inc.(196170)The antibody-drug conjugate (ADC) anticancer drug “Enhertu,” for which Alteogen Inc. provided subcutaneous (SC) formulation conversion technology, has been approved in Europe as a treatment for early-stage breast cancer. As Enhertu expands beyond the treatment of metastatic cancer to the field of early-stage breast cancer—where a cure is the goal—the market potential for Alteogen Inc.’s SC conversion technology is expected to grow.

According to the biotech industry on the 28th, Daiichi Sankyo announced on the 27th that the European Commission (EC) had approved Enhertu as adjuvant therapy following surgery for adult patients with HER2-positive early-stage breast cancer. The approval applies to patients who still have residual invasive disease despite having received preoperative taxane-based chemotherapy and HER2-targeted therapy.

This approval is significant because it marks the first time Enhertu has been authorized in Europe as a curative treatment for early-stage breast cancer. Whereas it was previously used primarily to treat inoperable or metastatic cancer, it can now also be used to reduce the risk of recurrence following surgery.

In the global Phase 3 clinical trial (DESTINY-Breast05) that formed the basis for this approval, Enhertu reduced the risk of invasive disease recurrence or death by 53% compared to the current standard of care, trastuzumab emtansine (T-DM1). The 3-year invasive disease-free survival (IDFS) rate was 92.4% in the Enhertu group and 83.7% in the T-DM1 group, a difference of 8.7 percentage points.

The expansion of Enhertu’s indications is also accelerating. Following its approval in Europe last June as a treatment for HER2-positive metastatic solid tumors, Enhertu received approval in September as a first-line treatment for HER2-positive metastatic breast cancer in combination with pertuzumab. Including this latest approval for early-stage breast cancer, the drug has secured three approvals in Europe over the past four months.

This expansion of Enhertu’s therapeutic indications is also a positive factor for Alteogen Inc. In November 2024, Alteogen Inc. signed an exclusive technology transfer agreement with Daiichi Sankyo to develop a subcutaneous (SC) formulation of Enhertu. The agreement is valued at up to $300 million (approximately 397.5 billion won), of which $20 million (approximately 26.5 billion won) is a non-refundable upfront payment. The remaining amount, up to $280 million (approximately 371 billion won), consists of milestones tied to development, approval, and sales. Following commercialization, Altheogen will also receive separate royalties based on net sales.

The technology provided by Alteogen Inc. is the recombinant human hyaluronidase “ALT-B4.” This technology aids in the absorption and diffusion of the drug when converting a biopharmaceutical administered via intravenous (IV) injection to a subcutaneous (SC) injection. Daiichi Sankyo began Phase 1 clinical trials for Enhertu SC last year and is currently evaluating its safety and pharmacokinetic properties in patients with recurrent or metastatic solid tumors.

In particular, as Enhertu is being expanded for use as a treatment for early-stage breast cancer, the commercial value of the SC formulation could also increase. This is because, for patients receiving repeated doses of anticancer drugs to prevent recurrence after surgery, shorter administration times can enhance the convenience of treatment. From the perspective of medical institutions, there is also the benefit of reducing the time and facility burdens associated with administering anticancer drugs. If Enhertu SC succeeds in clinical trials and regulatory approval in the future, the opportunity for Alteogen Inc. to receive milestone payments and secure sales royalties could also expand.

The results of the ADC subcutaneous injection conversion study released by Alteogen Inc. on the 26th are also drawing attention. At the European Society for Medical Oncology (ESMO 2026) conference held in Madrid, Spain, Alteogen Inc. presented the results of preclinical studies applying ALT-B4 to its proprietary HER2-targeted ADC, “ALT-P7.”

The preclinical study confirmed the potential to lower the maximum plasma concentration (Cmax) while maintaining bioavailability similar to that of intravenous administration, as well as to mitigate skin damage at the injection site, neutropenia, and hepatotoxicity. These results demonstrate that converting ADCs to a subcutaneous (SC) formulation could offer benefits not only in terms of improved convenience but also in terms of safety.

While the recent European approval of Enhertu does not directly trigger a milestone for Alteogen Inc., the expansion of Enhertu’s indications broadens the market potential for future SC formulations. If future clinical trials of Enhertu SC confirm drug exposure and safety comparable to intravenous administration, this is expected to have a positive impact on Alteogen Inc.’s ADC SC platform business.