Senhwa's CX-5461 Opens a New Frontier in Photoimmunotherapy; Multinational Study Published in Nucleic Acids Research

TAIPEI and SAN DIEGO, Aug. 12, 2026 /PRNewswire/ -- Senhwa Biosciences, Inc. (TPEx: 6492) today announced a significant research advance involving its investigational drug Pidnarulex (CX-5461). A multinational research team comprising investigators from Poland, Slovakia, France and Senhwa Biosciences in Taiwan found that, under specific cell-based experimental conditions, controlled light activation increased the cancer-cell-killing activity of CX-5461 by up to 96-fold and induced immunogenic cell death (ICD). The findings, published in the peer-reviewed journal Nucleic Acids Research, reveal that CX-5461 may have potential applications in photodynamic therapy and photoimmunotherapy in addition to its established research profile involving G-quadruplex (G4) targeting and DNA-damage-related mechanisms. The study opens a potential new development path for this clinical-stage asset.

Turning Photosensitivity into a Controlled Therapeutic Mechanism
Photosensitivity observed during the clinical development of CX-5461 has generally been viewed as a drug characteristic requiring risk management. In the new study, researchers reframed this property as a potentially controllable and spatially targeted therapeutic mechanism. By applying light of an appropriate wavelength to the tumor area, CX-5461 may be activated at the intended site, increasing local tumor-cell killing while limiting activity in non-illuminated tissue.

This light-switch concept could extend CX-5461 from a systemically administered anticancer agent into a photosensitizer with temporal and spatial control. The approach may warrant further investigation in tumors that are accessible to external light, endoscopy or fiber-optic delivery, including selected skin, oral and esophageal tumors.

Light Activation Triggers Tumor-Cell Killing and Immunogenic Cell Death
The study further showed that light-activated CX-5461 not only directly damaged cancer cells but also induced ICD. When cancer cells die through an immunogenic process, they release or expose danger-associated signals, including cell-surface calreticulin, extracellular ATP and high-mobility group box 1 (HMGB1). These signals can help dendritic cells recognize and take up tumor antigens, potentially initiating a T-cell-mediated antitumor immune response.

The therapeutic objective may therefore extend beyond destroying an illuminated local tumor. By making antigens from dying cancer cells more visible to the immune system, the treatment could provide a biological basis for using localized therapy to stimulate a broader antitumor immune response.

Preclinical Findings Support an In Situ Cancer Vaccine Concept
In preclinical mouse studies, animals whose tumors regressed after treatment with CX-5461 and light exposure showed suppressed tumor growth when subsequently challenged with the same cancer cells. The observation suggests that treatment may establish tumor-specific immune memory and supports further investigation of an in situ cancer vaccine concept. Under this approach, the patient's own tumor could serve as the source of tumor antigens, allowing an immune response to be initiated at the treatment site without the need to manufacture an external vaccine in advance.

If validated through additional studies, this mechanism could also be explored in combination with immune checkpoint inhibitors targeting PD-1 or PD-L1, with the goal of broadening or prolonging antitumor immune activity. These findings are preclinical and require confirmation in additional animal studies and human clinical trials.

Expanding the Potential Value of an Existing Clinical-Stage Asset
In drug development, a molecule can gain a second life when its existing properties and mechanisms are understood in a new way. CX-5461 has already generated a body of development data across chemistry, manufacturing and controls, toxicology, pharmacology and human clinical safety. The new research reframes photosensitivity as a potentially useful therapeutic mechanism and extends the molecule's research potential beyond G4 targeting and DNA-damage response into photodynamic therapy, photoimmunotherapy and immune-combination strategies.

Compared with developing an entirely new molecule from the outset, identifying a new mechanism and potential indications for an existing clinical-stage asset may support development continuity and broaden its potential product lifecycle, subject to successful preclinical, regulatory and clinical evaluation.

Next Steps
Senhwa views these findings as an important starting point for repositioning the value of CX-5461. Based on further validation, the Company plans to evaluate suitable tumor types, dosing and illumination conditions, light-delivery technologies and potential combination strategies. Senhwa will also seek multinational academic and industry collaborations to support the clinical translation of this photoimmunotherapy approach.

Additional preclinical and regulatory work will be required before clinical development can proceed. The safety and efficacy of CX-5461 as a photodynamic or photoimmunotherapy treatment have not been established in human clinical trials, and CX-5461 has not been approved for commercial use in these applications.

Please find more details via linkage below:
https://academic.oup.com/nar/article/54/15/gkag777/8758773

About Senhwa Biosciences
Senhwa Biosciences, Inc. is a Taiwan-based biotechnology company developing novel oncology therapeutics for cancers with significant unmet medical needs. Its pipeline includes CX-5461 and CX-4945, which are being evaluated in solid tumors and hematologic malignancies through international clinical and research collaborations. For more information, visit https://www.senhwabio.com.

SOURCE SENHWA BIOSCIENCES, INC.