FDA Grants Soligenix Orphan Drug Designation for the Treatment of T-cell Lymphoma

Extension of hypericin orphan designation beyond cutaneous T-cell lymphoma

PRINCETON, N.J., Sept. 9, 2021 /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 Office of Orphan Products Development of the United States (U.S.) Food and Drug Administration (FDA) has granted orphan drug designation to the active ingredient hypericin for the treatment of T-cell lymphoma, extending the target population beyond cutaneous T-cell lymphoma (CTCL) as previously granted. 

The U.S. Orphan Drug Act is intended to assist and encourage companies to develop safe and effective therapies for the treatment of rare diseases and disorders.  In addition to providing a seven year term of market exclusivity upon final FDA approval, orphan drug designation also positions Soligenix to be able to leverage a wide range of financial and regulatory benefits, including government grants for conducting clinical trials, waiver of expensive FDA user fees for the potential submission of a New Drug Application (NDA), and certain tax credits.

"The FDA's decision to grant and expand our hypericin orphan drug designation beyond CTCL signifies an important step for Soligenix as we continue to advance the program toward NDA filing in the first half of 2022," stated Christopher J. Schaber, PhD, President & Chief Executive Officer of Soligenix.  "HyBryte™'s biologic activity was clearly demonstrated in the positive Phase 3, pivotal FLASH (Fluorescent Light Activated Synthetic Hypericin) study in patients suffering with early stage CTCL.  The marketing exclusivity that this broadened orphan drug designation imparts adds significantly to the existing patent estate surrounding hypericin."

About HyBryte™

HyBryte™ (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 visible light 16 to 24 hours later which triggers apoptosis of the cell.  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 previously received orphan drug and fast track designations from the U.S. FDA, as well as orphan designation from the European Medicines Agency (EMA) and Promising Innovative Medicine (PIM) and "Innovation Passport" under the Innovative Licensing and Access Pathway (ILAP) from the Medicines and Healthcare Products Regulatory Agency (MHRA) of the United Kingdom for CTCL.

The Phase 3 FLASH (Fluorescent Light Activated Synthetic Hypericin) 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, 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 the first 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