Soligenix Receives European Patent for Improved Production of Synthetic Hypericin

Active Ingredient in HyBryte™ for the Treatment of Cutaneous T-Cell Lymphoma

PRINCETON, N.J., Sept. 3, 2024 /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 European Patent Office has granted the patent entitled "Systems and Methods for Producing Synthetic Hypericin".  The newly issued patent's claims are directed to a novel, highly purified form of synthetic hypericin manufactured through a unique proprietary process.  Synthetic hypericin is the active pharmaceutical ingredient in HyBryte™, the Company's photodynamic therapy for the treatment of cutaneous T-cell lymphoma (CTCL), set to initiate a confirmatory Phase 3 clinical trial before the end of the year. This new European granted patent (EP3423428) is a related patent to US Pat. No. 10,053,413, previously issued in the United States (US). Both patents are expected to expire in 2036, and form part of a larger patent family, including previously granted US patents covering methods of use (US Pat. No. 7,122,518) and methods of synthesis (US Pat. No. 8,629,302), as well as other granted patents throughout the world.

HyBryte™ is a novel, first-in-class, photodynamic therapy that combines synthetic hypericin, a highly potent photosensitizer that is applied to the cancerous CTCL skin lesions and activated using a safe, visible light treatment.  This treatment approach avoids the risk of secondary malignancies (including melanoma) inherent with the frequently employed DNA-damaging chemotherapeutic drugs and other photodynamic therapies that are dependent on ultraviolet exposure. 

HyBryte™ has shown statistically significant efficacy in a Phase 3 randomized, placebo-controlled trial (FLASH trial, Fluorescent Light Activated Synthetic Hypericin) and will be initiating a second confirmatory Phase 3 placebo-controlled study (FLASH2) in 4Q 2024. Additional supportive  studies have demonstrated the utility of longer treatment times (Study RW-HPN-MF-01), the lack of significant systemic exposure to hypericin after topical application (Study HPN-CTCL-02) and its relative efficacy and tolerability compared to Valchlor® (Study HPN-CTCL-04).

"This recently issued patent continues to expand, strengthen and protect our synthetic hypericin patent estate," stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. "With important contributions from key patient advocacy organizations, such as the Cutaneous Lymphoma Foundation, we look forward to completing the confirmatory Phase 3 CTCL study to potentially address the unmet medical need that currently exists in this orphan disease."

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 US Food and Drug Administration (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 CAILS 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