Positive Clinical Results from HyBryte™ Comparative Study Evaluating HyBryte™ Against Valchlor® in the Treatment of Cutaneous T-Cell Lymphoma Published in Oncology and Therapy

HyBryte™ demonstrates more rapid and robust treatment response compared toValchlor® during 12-week treatment course

PRINCETON, N.J., April 2, 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 the positive results of its comparability study evaluating HyBryte™ (synthetic hypericin) versus Valchlor® (mechlorethamine) for the treatment of cutaneous T-cell lymphoma (CTCL) have been published in Oncology and Therapy. 

"Being able to share the important results of this clinical trial with the world through publication in Oncology and Therapy is a privilege and highlights the clinical significance of our work with HyBryte™," stated Brian Poligone, MD, PhD, Director of the Rochester Skin Lymphoma Medical Group, Fairport, NY, and Principal Investigator for the comparability study. "Despite the small study sample size and a randomization that lead to the HyBryte™ group having patients with more extensive disease, HyBryte™ performed well and the results are consistent with previous studies demonstrating its rapid onset of action and benign safety profile compared to one of the most widely prescribed approved drugs for early-stage CTCL. The positive effect this therapy can have for patients and the outstanding safety profile that HyBryte™ continues to demonstrate are very encouraging."

The purpose of the study was to obtain preliminary comparative assessment of the safety and efficacy of HyBryte™ versus Valchlor® following 12 weeks of treatment as measured in 3 to 5 prospectively identified index lesions for each patient. At the end of the 12-week treatment period, 60% of the HyBryte™ patients met the prospectively defined level of "Treatment Success" (≥50% improvement in their cumulative mCAILS score compared to Baseline) compared to only 20% of the Valchlor® patients; although due to the small sample size the results do not achieve statistical significance. Of the remaining two HyBryte™ patients that did not achieve treatment success, both saw a substantial (≥30%) reduction in their mCAILS score. In contrast, in the Valchlor® group, of the remaining 4 patients that did not achieve treatment success, one worsened and dropped from the study, one improved less than 30% and two improved greater than 30%. The average cumulative improvement in mCAILS at 12 weeks was 52.5% in the HyBryte™ patients versus 34.7% in the Valchlor® patients. HyBryte™ was well tolerated in all patients whereas 1 of the 5 patients receiving Valchlor® had to be withdrawn from the trial because of a clinically significant allergic contact dermatitis from Valchlor®.

When comparing the tolerance of the topical therapies (i.e., reactions where the drug was applied to the skin) in this trial, it is notable that all patients tolerated HyBryte™ well and had no adverse events "related" to the therapy. In contrast, 60% of the Valchlor® treated patients had at least one adverse event "related" to the therapy. These adverse events in the Valchlor® group included rashes, application site sensitivity, allergic contact dermatitis, and dermatitis, with one patient requiring steroid treatment, one requiring temporary interruption of Valchlor® treatment, and one requiring permanent discontinuation of Valchlor®. No such instances were reported in the HyBryte™ group.

About Oncology and Therapy

Oncology and Therapy is an international, open access, peer-reviewed, and rapid publication journal. The scope of the journal is broad, dedicated to the publication of high-quality clinical, observational, real-world, patient care, and health outcomes research around the discovery, development, and use of therapeutics and interventions across all areas of oncology. The key features of the journal are rapid publication, open access, inclusivity, personal service, digital features, plain language summaries and novel article types.

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