Soligenix Announces HyBryte™ Clinical Summary Published in "Expert Opinion on Investigational Drugs"

PRINCETON, N.J., March 19, 2026 /PRNewswire/ -- Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, announced today that a summary of all the clinical trials completed to date evaluating HyBryte™ (synthetic hypericin) as a treatment for cutaneous T-cell lymphoma (CTCL) has been published in the peer-reviewed medical journal Expert Opinion on Investigational Drugs. The publication "Topical Hypericin: A Promising Photodynamic Therapy for Early-Stage Cutaneous T-Cell Lymphoma" is authored by Brian Poligone, MD, PhD, the founder and Medical Director of the Rochester Skin Lymphoma Medical Group and the Director of Cancer Biology Research for the Rochester General Hospital Research Institute who has extensive clinical experience evaluating HyBryte™ with his team's participation in four HyBryte™ clinical studies. 

Expert Opinion on Investigational Drugs is an international monthly peer-reviewed journal, evaluating drugs in preclinical and clinical development.  Authors are encouraged to express their Expert Opinion of the status of the research under review and its impact on clinical practice, rather than simply review the available data.  The audience consists of scientists, managers and decision-makers in the pharmaceutical industry, and others closely involved in research and development.

"Topical synthetic hypericin represents a paradigm shift in the skin-directed management of early-stage CTCL. Its unique mechanism, excellent safety profile, and robust clinical efficacy position it as a formidable potential new agent in the therapeutic armamentarium," stated Dr. Poligone, Director of the Rochester Skin Lymphoma Medical Group. "Following the positive results from the previous Phase 2 and 3 studies I participated in, as well as the ongoing confirmatory FLASH2 Phase 3 study, I was honored to be invited by Expert Opinion on Investigational Drugs to provide a definitive analysis of the HyBryte™ clinical data landscape. HyBryte™ has been demonstrated to have a non-mutagenic mechanism of action, uses a non-carcinogenic light source and appears to have improved tolerability relative to available therapies such as mechlorethamine. The rapid response rates and the efficacy demonstrated on thicker plaque lesions, combined with its activity in difficult to treat disease variants like folliculotropic mycosis fungoides, makes HyBryte™ a potential broad-spectrum, first-line option for patients with early-stage CTCL. We look forward to continuing our support of Soligenix in the development of HyBryte™."

"We are pleased to have Dr. Poligone and his team review the compelling data generated from the HyBryte™ clinical program, enabling the medical community to evaluate its safety, efficacy and utility in early-stage CTCL," stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix.  "We look forward to continuing our work with Dr. Poligone and all our principal investigators as we move towards completing patient enrollment in the FLASH2 Phase 3 study later this year, with an interim analysis of this study expected in 2Q 2026."

About HyBryte™

HyBryte™ (research name SGX301) is a novel, first-in-class, photodynamic therapy utilizing safe, visible light for activation. The active ingredient in HyBryte™ is synthetic hypericin, a potent photosensitizer that is topically applied to skin lesions that is taken up by the malignant T-cells, and then activated by safe, visible light approximately 24 hours later. The use of visible light in the red-yellow spectrum has the advantage of penetrating more deeply into the skin (much more so than ultraviolet light) and therefore potentially treating deeper skin disease and thicker plaques and lesions. This treatment approach avoids the risk of secondary malignancies (including melanoma) inherent with the frequently employed DNA-damaging drugs and other phototherapy that are dependent on ultraviolet exposure. Combined with photoactivation, hypericin has demonstrated significant anti-proliferative effects on activated normal human lymphoid cells and inhibited growth of malignant T-cells isolated from CTCL patients. In a published Phase 2 clinical study in CTCL, patients experienced a statistically significant (p=0.04) improvement with topical hypericin treatment whereas the placebo was ineffective. HyBryte™ has received orphan drug and fast track designations from the FDA, as well as orphan designation from the European Medicines Agency (EMA).

The published Phase 3 FLASH trial enrolled a total of 169 patients (166 evaluable) with Stage IA, IB or IIA CTCL. The trial consisted of three treatment cycles. Treatments were administered twice weekly for the first 6 weeks and treatment response was determined at the end of the 8th week of each cycle. In the first double-blind treatment cycle (Cycle 1), 116 patients received HyBryte™ treatment (0.25% synthetic hypericin) and 50 received placebo treatment of their index lesions. A total of 16% of the patients receiving HyBryte™ achieved at least a 50% reduction in their lesions (graded using a standard measurement of dermatologic lesions, the modified Composite Assessment of Index Lesion Severity [mCAILS] score) compared to only 4% of patients in the placebo group at 8 weeks (p=0.04) during the first treatment cycle (primary endpoint). HyBryte™ treatment in this cycle was safe and well tolerated.

In the second open-label treatment cycle (Cycle 2), all patients received HyBryte™ treatment of their index lesions. Evaluation of 155 patients in this cycle (110 receiving 12 weeks of HyBryte™ treatment and 45 receiving 6 weeks of placebo treatment followed by 6 weeks of HyBryte™ treatment), demonstrated that the response rate among the 12-week treatment group was 40% (p