Japan Approves Alpha DaRT, a Breakthrough in Cancer Radiation Therapy

TOKYO – February 24, 2026 – Japan’s health regulators have granted landmark approval to a novel cancer treatment, Alpha DaRT, offering a new lifeline to patients with unresectable or recurrent head and neck cancers who have exhausted conventional options. The decision makes Japan the first country in the world outside of Israel, where the technology was developed, to clear the innovative therapy for clinical use, signaling a potential shift in global MedTech adoption strategies.

The approval, known as Shonin, was granted to Israeli developer Alpha Tau Medical Ltd. and its Japanese partner, HekaBio K.K., which will lead the commercial launch. The therapy, short for Diffusing Alpha-emitters Radiation Therapy, represents a new frontier in brachytherapy, using alpha particles to deliver a potent and highly localized attack on solid tumors while minimizing damage to surrounding healthy tissue.

A New Hope for Untreatable Cancers

For patients diagnosed with locally advanced or recurrent head and neck cancer, treatment pathways can be fraught with challenges. When tumors are deemed inoperable or fail to respond to standard treatments like chemotherapy and conventional radiation, options become severely limited. Alpha DaRT is poised to address this critical unmet need.

“Results from this domestic clinical trial show that Alpha DaRT presents strong potential and meaningful progress in treating cancers unresponsive to standard therapies,” said Dr. Jun Itami, Director of the High-Precision Radiation Therapy Center at Shin-Matsudo Central General Hospital, who was a key figure in the clinical trials. “Demonstrating the effectiveness of intratumoral alpha-particle therapy—long considered challenging to implement—marks an important clinical milestone and introduces a new treatment option.”

Dr. Itami emphasized the psychological value for patients and their families in having an additional therapeutic option. The approval provides not just a new tool for oncologists but also a renewed sense of hope for those facing the most difficult prognoses.

The Science of a Precision Strike

Alpha DaRT’s innovation lies in its unique mechanism for delivering one of the most powerful forms of radiation directly inside a tumor. Unlike conventional external beam radiation, which uses gamma or X-rays that must pass through healthy tissue to reach their target, Alpha DaRT works from the inside out.

The procedure involves inserting several tiny, seed-like sources containing an isotope, Radium-224, directly into the tumor mass. As the Radium-224 decays, it releases a series of short-lived daughter atoms. These atoms diffuse through the tumor, continuously emitting high-energy alpha particles along their path.

Alpha particles are potent cell killers. They cause complex and irreversible double-strand breaks in the DNA of cancer cells, leading to rapid cell death. A key advantage is their extremely short range—typically less than 100 microns in tissue. This ensures their destructive power is confined almost exclusively to the tumor, sparing adjacent healthy organs and structures. This precision is particularly vital in the complex anatomy of the head and neck.

Clinical studies have shown that the therapy is not only effective but also may stimulate an anti-tumor immune response, a phenomenon that could have broader implications for treating cancer systemically.

Japan Takes the Lead: A Global First

The approval marks a significant strategic victory for both Alpha Tau and HekaBio. Securing a Japanese Shonin ahead of approvals from the U.S. Food and Drug Administration (FDA) or the European Medicines Agency (EMA) is an exceptionally rare event for a foreign-developed medical device.

“An approval in Japan in advance of the US and Europe for a foreign-originated new category medical device is an extremely rare event, and we’re grateful to all of our partners who made this possible,” stated Robert E. Claar, CEO of HekaBio. He noted that the Alpha DaRT program has been the primary focus for his team for seven years, a testament to the dedication required to navigate Japan’s rigorous regulatory landscape.

This “Japan-first” milestone underscores the country’s growing role as an early adopter of breakthrough medical technologies, driven by a sophisticated healthcare system and an urgent need to address diseases affecting its aging population. HekaBio, acting as the Designated Marketing Authorization Holder (DMAH), was instrumental in managing the complex local clinical trials and regulatory submissions required by Japan's Pharmaceuticals and Medical Devices Agency (PMDA).

For Alpha Tau, the Japanese approval is a powerful validation of its platform. “Receiving Shonin approval in Japan is a significant milestone for Alpha Tau and for the Alpha DaRT platform,” said Uzi Sofer, CEO of Alpha Tau Medical. “We believe this approval represents an important first step toward broader clinical evaluation of Alpha DaRT.”

The Clinical Evidence Behind the Approval

The Japanese approval was based on compelling data from a domestic clinical trial involving patients with recurrent head and neck cancer. The study demonstrated an overall response rate of 81.8%, with three patients achieving a complete response (disappearance of the tumor) and six achieving a partial response. The safety profile was deemed acceptable, with most adverse events being mild to moderate and localized to the treatment area.

These results are consistent with broader international findings. A pooled analysis of multiple studies published in Cancers showed that Alpha DaRT achieved a complete response in 89% of treated lesions, with a two-year local recurrence-free survival rate of 77%. This level of local control is substantially higher than the 25% reported for conventional re-irradiation in similar patient populations.

Following the approval, Alpha Tau and HekaBio will work with Japanese clinicians to complete a post-market surveillance study to gather further real-world data. The companies will also begin discussions with Japan’s Ministry of Health, Labour and Welfare (MHLW) regarding reimbursement to ensure broad patient access.

While Alpha DaRT is initially approved for head and neck cancer, Alpha Tau is actively pursuing its use for a wide range of other solid tumors. The company has multiple ongoing trials in the United States and Europe for challenging cancers such as glioblastoma, pancreatic cancer, and prostate cancer, having already received Breakthrough Device Designation from the FDA for certain indications. This first major market approval in Japan provides powerful momentum for the company’s global expansion and its mission to transform the treatment of solid tumors.