Hong Kong Patent Granted to Synthetic Hypericin for CTCL

Recently, biopharmaceutical company Soligenix, Inc. shared that it had been granted a patent (#16102842.8) in Hong Kong for the use of synthetic hypericin to treat patients with cutaneous T-cell lymphoma (CTCL). The company has a particular interest in this because its lead product candidate, SGX301, uses synthetic hypericin as the main active ingredient.


SGX301, or synthetic hypericin, is Soligenix’s photodynamic therapy for first-line use in patients with early-stage CTCL. The Mayo Clinic describes photodynamic therapy as:

a two-stage treatment that combines light energy with a drug (photosensitizer) designed to destroy cancerous and precancerous cells after light activation.

In this case, SGX301 is applied topically to any skin issues. After 16-24 hours have passed, researchers activate SGX301 using deeply penetrating fluorescent light. Unlike other therapies which use ultraviolet light, this type of therapy does not cause additional cancers or malignancies. The FDA granted Orphan Drug and Fast Track designations to SGX301, which also received Orphan Drug designation in Europe.

Synthetic hypericin showed clinical improvement in the Phase 3 FLASH clinical trial. 166 patients enrolled. Patients underwent three treatment cycles: 2x weekly for the first 6 weeks, with the responses recorded by week 8. In the first cycle, 116 (69.9%) received 0.25% SGX301 while the other 50 (30.1%) received a placebo. 19 patients who used SGX301 saw at least 50% lesion reduction compared to only 2 patients in the placebo group.

During the second cycle, all 155 participants received SGX301, though 110 had 12 weeks of treatment while the other 45 had 6 weeks of a placebo and 6 weeks of active treatment. 40% of patients responded to treatment. SGX301 also showed significantly better rates of CTCL lesion and plaque improvement than the placebo. In the final cycle, all patients were able to use SGX301, with 49% of those who went through all three cycles achieving some response. In all three arms of the trial, SGX301 was safe and well-tolerated.

Cutaneous T-Cell Lymphoma (CTCL)

There are multiple forms of cutaneous T-cell lymphoma (CTCL), a cancer characterized by abnormal malignant T-cells in the skin. These include lymphomatoid papulosis, mycosis fungoides, Sézary syndrome, granulomatous slack skin, and Woringer-Kolopp disease. CTCL also belongs to a larger group of disorders called non-Hodgkin’s lymphomas (NHLs), though CTCL makes up only around 4% of all NHL cases. Normally, T-cells play a role in immune response. However, the malignant cells cause lesions, rashes, plaques, and tumors on the skin. Typically, if caught early, someone may live for 10+ years after diagnosis. Unfortunately, if CTCL is caught at a later stage, it is often fatal with 2-3 years. There is currently no cure. 10% of those with later-stage CTCL develop serious complications associated with their condition.

Symptoms vary based on the specific subset of CTCL. For example, patients with Sézary syndrome may experience:

  • Hair loss
  • Nail distortion and discoloration
  • Enlarged liver and spleen
  • Thickened skin on the hands and feet
  • Abnormal accumulation of fluid under the skin

Those with mycosis fungoides, on the other hand, usually experience an initial stage with itchy, dry skin or a rash, typically on the butt; a second stage with swollen lymph nodes and intensely itchy skin plaques; and a third stage with a tumor that could ulcerate.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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