SGX302, Plaque Psoriasis Treatment for Mild to Moderate Psoriasis
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Background on Psoriasis
Psoriasis of some form may be present in up to 125 million people worldwide, with approximately 75% of patients experiencing mild to moderate disease. Psoriasis is the most common immune-mediated inflammatory skin disease. According to the World Health Organization (WHO) Global Report on Psoriasis 2016 , the prevalence of psoriasis is between 1.5% and 5% in most developed countries, with some suggestions of incidence increasing with time. Approximately 8 million patients in the US are believed to have this chronic disease.
Psoriasis can present in a number of forms but plaque psoriasis is the most common. Psoriasis can be caused / influenced by a variety of factors including genetics, skin injury, temperature, stress, smoking and secondhand-smoke, heavy alcohol consumption and certain medications More information on psoriasis can be found here. There are a number of plaque psoriasis treatment alternatives, the best-known of which are targeted specifically at moderate or severe disease.
While there are treatment options for mild to moderate disease, their use is constrained by limited efficacy and/or the potential for acute and long term toxicity. SGX302 with light therapy for plaque psoriasis is different.
Our Approach: SGX302
SGX302 is designed to be a safe alternative for treatment of mild to moderate psoriasis, ideally enabling patients to undergo more treatments to manage their disease while accumulating significantly less risks/toxicities
What is photodynamic light therapy for psoriasis?
Photodynamic light therapy for psoriasis is a two part treatment. First the product is applied topically only where it is needed. That is followed up by a treatment of light to activate the drug.
Photodynamic light therapy in general can use many different kinds of light – UV A, UV B, fluorescent light, lasers, etc. The specific light used depends on the drug molecule and how much energy is needed to activate it.
What is SGX302 Plaque Psoriasis Treatment?
SGX302 is a photodynamic light therapy for psoriasis treatment which uses synthetically manufactured hypericin applied as an ointment and activated with visible fluorescent light. Hypericin is one of the most photoactive compounds known – it is easily activated with relatively low energy light. This makes it ideal for photodynamic therapy because it can be activated with fluorescent light, instead of UV A or UV B light, which are associated with increased cancer risks.
Mechanism of Action
Hypericin, the active ingredient in SGX302, is absorbed by cells in the treated skin and can then be activated by fluorescent light.
When hypericin is activated it creates oxygen radicals that subsequently cause cellular toxicity, killing the targeted cells.
As both the concentration of the drug inside the treated cells and the light intensity increases, there is more destruction of the targeted cells. This may result in clearing of the psoriasis lesion. Because the hypericin is applied topically, it only targets the cells in the lesion, and does not circulate at a high concentration within the body, further reducing toxicity.
Importantly, the mechanism by which the activated hypericin kills cells does NOT involve mutation of the DNA. Therefore, mutagenic risk is minimized. Similarly, use of fluorescent light reduces the carcinogenic risk.
In one of the largest, Phase 3, randomized placebo-controlled trials ever conducted in early stage CTCL, HyBryte™ reduced lesion size in patients in as little as 6 weeks of twice weekly therapy, and this improvement increased the longer plaque psoriasis treatment was continued.
More details on the mechanism of action of hypericin can be found on our HyBryte page and in our Reference Literature webpage.
Clinical Studies & Commercialization
Synthetic hypericin is the active ingredient in both SGX302 and HyBryte™ treatment for cutaneous T-cell lymphoma (CTCL). Based on our recent clinical success with the Phase 3 FLASH study in CTCL, a cancer in which malignant T-cells migrate to the surface of the skin, we are expanding the use of synthetic hypericin to mild to moderate psoriasis. Based on the results in the FLASH study in CTCL, as well as a proof of concept study in psoriasis, we intend to start a Phase 2a study in mild to moderate psoriasis patients in the second half of 2022.
There are other photodynamic therapies approved for use as plaque psoriasis treatments. Unfortunately these treatments require the use of ultraviolet A (UV A) light for photoactivation, resulting in black box warnings for malignant melanoma, eye disease and other skin damage. As a consequence of these side effects, these other photodynamic therapies can only be used a limited number of times, despite their efficacy. SGX302 offers the potential to overcome these limitations, enabling potentially unlimited psoriasis treatments, and potentially home use, of an effective photodynamic light therapy. Commercialization of SGX302 will follow commercialization of HyBryte™ in CTCL, assuring familiarity of many dermatologists with this novel visible photodynamic light therapy.
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Previous Clinical Studies with SGX302
Topical, synthetic hypericin has demonstrated safety in a Phase 1 clinical study in healthy volunteers. In a proof of concept Phase 1/2, placebo-controlled, clinical study in patients with cutaneous T-cell lymphoma (CTCL) and psoriasis, the drug was safe, well tolerated, and effective in ameliorating the skin lesions.
Other Potential Uses for Topical Synthetic Hypericin
In one of the largest, Phase 3, randomized placebo-controlled trials ever conducted in early stage CTCL, HyBryte™ reduced lesion size in patients in as little as 6 weeks of twice weekly therapy, and this improvement increased the longer treatment was continued. Unlike psoriasis, the T-cells in CTCL are malignant. The recent placebo controlled, double blind, randomized FLASH study in CTCL demonstrated a statistically significant increase in treatment response (that is, an improvement in lesion scores of at least 50%) in patients treated twice weekly with HyBryte™.
Synthetic hypericin, the active ingredient in SGX302, has Fast Track designation for the treatment of CTCL in the United States.
Synthetic hypericin, the active ingredient in SGX302, was awarded an “Innovation Passport” for the treatment of early stage CTCL in adults under the UK’s Innovative Licensing and Access Pathway.
Synthetic hypericin, the active ingredient in SGX302, has Promising Innovative Medicine designation from the United Kingdom Medicines and Healthcare products Regulatory Agency for the treatment of CTCL.
Synthetic hypericin, the active ingredient in SGX302, has orphan drug designation in the United States for the treatment of T-cell lymphoma and CTCL and in Europe for CTCL.
Soligenix has a strong worldwide intellectual property position on the use of photoactivated hypericin.
Orphan Drug designation also confers 7 years market exclusivity in the US and 10 years in Europe, if approved.
Our pipeline focuses on orphan and unmet medical need across a range of indications