A targeted therapy that uses near-infrared lasers to destroy tumors is producing survival results that have stunned oncologists. Now researchers want to know how far it can go
The patient had already exhausted most of his options. His head and neck cancer had returned after surgery and radiation, leaving him in a category that oncologists describe with bleak clinical precision: recurrent, unresectable. The standard next step, systemic drug therapy, carried a median survival of roughly eight months.
Instead, his doctors at Hiroshima University Hospital tried something different. They infused him with a specially engineered drug and, about 24 hours later, directed a near-infrared laser at his tumor. Within minutes, at the cellular level, cancer cells began to rupture. Healthy tissue around them was largely untouched.
The treatment, called near-infrared photoimmunotherapy, or NIR-PIT, sits at an unusual intersection of immunology, oncology and physics. And according to a retrospective study published in January 2026 by researchers at Hiroshima University, patients who received it recorded a median survival of 35 months. Those who received standard drug therapy survived a median of eight months.
In a field where progress is typically measured in weeks, that gap has seized the attention of cancer researchers worldwide.
“We are combining the light-activated approach with engineered protein technology, using both avenues to eliminate the tumor,” said Dr. Girgis Obaid, a biomedical engineer at the University of Texas at Dallas who studies photodynamic cancer therapies. “The precision of what you can achieve with this approach is genuinely unlike anything we have had before.”
How the Therapy Works
The drug at the center of NIR-PIT, cetuximab sarotalocan sodium, is a conjugate: two components fused into one molecule. The first is cetuximab, an antibody that has been used in cancer treatment for years because of its ability to home in on a protein called EGFR, which is overexpressed in many head and neck tumors. The second is a light-sensitive dye called IR700.
After the drug is infused intravenously, it circulates through the body and accumulates in tumor cells, drawn there by the antibody’s affinity for EGFR. A day later, clinicians use fiber-optic probes, placed on the skin or inserted directly into tissue, to deliver near-infrared light at a wavelength of 690 nanometers.
Unlike visible light, near-infrared penetrates tissue more deeply and with greater control, allowing it to reach tumors that might otherwise be inaccessible. When the laser activates the IR700 dye, it triggers a rapid physical change in the drug molecule that causes cancer cells to swell and burst, a process known as necrosis.
The procedure itself typically lasts between 60 and 90 minutes. Patients are under general anesthesia. There is no ionizing radiation. Compared with salvage surgery, which can involve extensive reconstruction and carries significant risks of complications, NIR-PIT is, by the standards of late-stage cancer treatment, relatively contained.
An Immune System Surprise
What researchers did not fully anticipate when the therapy was first developed by Dr. Hisataka Kobayashi at the National Cancer Institute was the immune response it appears to set off.
When cancer cells rupture, they release a flood of tumor antigens, molecular signals that the immune system can recognize as foreign. Dendritic cells in the vicinity pick up these signals and activate T-cells, which can then circulate through the body and attack cancer cells at other sites. The phenomenon, known as immunogenic cell death, means that a treatment delivered to one tumor may potentially trigger a systemic defense.
“Light-triggered cell destruction can activate the body’s immune system and enhance its ability to mount an attack against cancer,” said Dr. Mads Daugaard, a cancer researcher at the Vancouver Coastal Health Research Institute who has studied similar immunological pathways. “That is the part of this that could really change the calculus of how we sequence treatments.”
The implication is significant. NIR-PIT may be most powerful not as a standalone therapy but as a primer, a way to make the immune system more receptive to checkpoint inhibitors and other immunotherapies that have transformed oncology over the past decade. Clinical researchers are already designing trials to test these combinations.
Japan’s Approval and the Path to Wider Use
NIR-PIT’s clearest institutional endorsement came in January 2021, when Japan approved the therapy for national insurance coverage for unresectable and recurrent head and neck cancers, making it the first country to do so. The approval was the result of years of clinical development led in part by Rakuten Medical, the Tokyo-based company that holds the commercial license for the technology.
The approval covered a narrow population, patients with cancers that had already proven resistant to other interventions, but it established a regulatory precedent and gave researchers a body of real-world data to analyze.
That data has only strengthened the case for broader study. The Hiroshima University findings, while retrospective and therefore limited in the conclusions they can support, drew attention because of how stark the survival difference was. Researchers were careful to note that patients in the NIR-PIT group may have differed in important ways from those receiving drug therapy, and that a randomized controlled trial would be needed to confirm the results.
Still, in a disease setting where the prognosis has remained stubbornly grim for decades, even preliminary evidence of this magnitude is treated seriously.
Expanding the Target List
Because the therapy’s targeting depends on antibodies rather than the light itself, the platform can in theory be adapted to any cancer type for which a suitable antibody exists. EGFR is overexpressed in head and neck tumors, but other proteins are overexpressed in other cancers, and researchers are racing to build new conjugates.
At UT Southwestern Medical Center and the University of Texas at Dallas, teams are developing engineered proteins called “betabodies” designed to target abdominal cancers, including advanced gastric tumors.
“We are excited to participate in the development of this novel strategy for the treatment of recalcitrant tumors,” said Dr. Rolf Brekken, a professor of surgery and pharmacology at UT Southwestern who studies tumor microenvironments.
Other researchers are investigating photothermal therapy, a related but distinct approach that uses nanoparticles activated by light to generate localized heat inside tumors rather than causing them to rupture. Early results in bladder cancer have shown promise, though the approach has not yet advanced to large-scale clinical trials.
The Remaining Challenges
The therapy is not without its limitations, and researchers are candid about them.
Delivering near-infrared light to deeply embedded tumors remains a technical hurdle. Fiber-optic probes can reach many sites, but tumors located near critical structures or in difficult anatomical positions may be harder to treat without risk of collateral damage. The 690-nanometer wavelength that activates the IR700 dye penetrates tissue well compared with visible light, but it is not unlimited in its reach.
Expanding the library of viable antibody targets is another challenge. Developing, testing and manufacturing a new conjugate for each cancer type is an expensive and time-consuming process, and not every protein that appears overexpressed in tumor cells will prove to be a reliable target in practice.
“The biology is genuinely exciting,” Dr. Obaid said. “But there is still real engineering and clinical work ahead before this is a standard option for patients beyond the current indications.”
Dr. Kobayashi, whose foundational research helped establish the field, has written that light-based targeted therapies could help patients avoid the side effects associated with surgery, radiation and chemotherapy. That promise, he and others argue, makes the remaining challenges worth confronting.
For patients with recurrent head and neck cancer, a group that has historically had few good options, photoimmunotherapy represents something rare: not an incremental advance, but a potential reimagining of what treatment can look like. Whether the survival numbers seen in Hiroshima hold up in larger, more rigorous trials will determine how far this light ultimately reaches.
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