Soligenix Seeking FDA Approval for Second Phase 3 Study of Innovative Treatment for Cutaneous T-Cell Lymphoma

Soligenix, Inc., a late-stage biopharmaceutical company, has taken a significant step forward in its mission to develop and commercialize products to treat rare diseases. The company has submitted a Type A Meeting Request to the U.S. Food and Drug Administration to discuss the design of a second Phase 3 pivotal study evaluating its product, HyBryte™ (hypericin sodium), for the treatment of early stage cutaneous T-cell lymphoma (CTCL).

This is the highest priority classification of meeting the FDA grants and is expected to take place within the next 30 days. If successful, this could lead to a groundbreaking new treatment for the millions of people suffering from this rare cancer.

At the April Type A meeting with the FDA, Soligenix were delighted to receive an enthusiastic response to their need for additional therapies in CTCL. The FDA’s willingness to collaborate and their insights into a clinical study design allowed Soligenix to develop a comprehensive proposal swiftly.

Soligenix are grateful for the FDA’s responsiveness, and are looking forward to a productive meeting to agree on a pivotal study design that can be implemented as soon as possible. The proposed protocol for the confirmatory study largely retains the key design aspects from the FLASH study, while taking into account the FDA’s initial feedback.

About HyBryte™

HyBryte™ (research name SGX301) is a revolutionary photodynamic therapy that harnesses the power of safe, visible light to deliver therapeutic effects on skin lesions. Its active ingredient, synthetic hypericin, is applied topically and taken up by malignant T-cells, before being activated by visible light 24 hours later. This approach benefits from the ability of the red-yellow spectrum of visible light to penetrate deeper into the skin, allowing for the treatment of thicker plaques and lesions.

In addition, it avoids the risk of secondary malignancies associated with DNA-damaging drugs and other phototherapies that involve ultraviolet exposure. In a published Phase 2 clinical study in CTCL, HyBryte™ demonstrated significant anti-proliferative effects and a statistically significant (p=0.04) improvement compared to placebo. As a result, HyBryte™ has received orphan drug and fast track designations from the FDA and orphan designation from the European Medicines Agency (EMA).

The recently published Phase 3 FLASH trial enrolled a total of 169 patients with Stage IA, IB or IIA CTCL. The trial consisted of three treatment cycles and the results were remarkable: 16% of the patients receiving HyBryte™ achieved a 50% reduction in their lesions at 8 weeks compared to just 4% of those receiving the placebo treatment! HyBryte™ proved to be safe and well-tolerated, making it an effective and reliable treatment option for CTCL.

The second open-label treatment cycle (Cycle 2) saw 155 patients receive HyBryte™ treatment of their index lesions – 110 receiving 12 weeks of HyBryte™ and 45 receiving 6 weeks of placebo followed by 6 weeks of HyBryte™.

The results were remarkable – a 40% response rate for the 12-week treatment group (p<0.0001 compared to placebo treatment in Cycle 1), and a statistically significant improvement (p<0.0001) between the two treatment groups. More importantly, HyBryte™ proved just as effective in treating both plaque and patch lesions of CTCL, a previously difficult feat. Importantly, HyBryte™ remained safe and well tolerated.

66% of patients opted to receive the optional HyBryte™ treatment during Cycle 3 of the study, which was focused on safety. This compassionate use of the product yielded promising results – 49% of those who received HyBryte™ throughout all 3 cycles of treatment showed a positive treatment response (p<0.0001 vs patients receiving placebo in Cycle 1).

It was also demonstrated that HyBryte™ is non-systemically available, thus reinforcing the product’s general safety profile. And despite extensive and prolonged use, HyBryte™ remained well tolerated at the end of Cycle 3.

The safety of HyBryte™ is of paramount importance, and was closely monitored throughout three treatment cycles and the 6-month follow-up period. Unlike currently available therapies, HyBryte™ does not cause DNA damage, making it a safer alternative with minimal risk of melanoma, other malignancies, skin damage, or premature skin aging.

There are no approved front-line therapies available, so treatment of CTCL is strongly motivated by the safety risk of each product. HyBryte™ may be the safest and most effective treatment for CTCL, with very limited systemic absorption, a non-mutagenic compound, and a light source that is not carcinogenic. So far, there is no evidence of any safety issues.

The National Cancer Institute and the FDA have both contributed to the advancement of research for CTCL treatment, with the NCI awarding Soligenix, Inc. a Phase II SBIR grant (#1R44CA210848-01A1) and the FDA awarding a $2.6 million Orphan Products Development grant to a prestigious academic institution to study the use of HyBryte™ for early-stage CTCL treatment in home settings. Thanks to their generous contributions, a groundbreaking Phase 3 FLASH study is now underway.

About Cutaneous T-Cell Lymphoma (CTCL)

CTCL is a type of cancer that affects the white blood cells, specifically T-cell lymphocytes. These cells migrate to the skin, where they cause a range of lesions, from patches to plaques and tumors. Unfortunately, there is no cure for CTCL, and mortality rates depend on the stage of the disease, ranging from 12 years in early stages to a mere 2.5 years in the advanced stages.

Although lesions can be treated and regress, they usually return in the same area or in new places. So, while CTCL is a serious and life-threatening condition, there is hope for those who have been diagnosed with it.

Cutaneous T-Cell Lymphoma (CTCL) is an uncommon form of Non-Hodgkin’s Lymphoma, affecting around 25,000 individuals in the United States alone. Annually, it is estimated that around 3,000 new cases are identified, constituting a mere 4% of the total population of those living with NHL. Little known, yet far from rare, CTCL is a serious illness that should not be overlooked.

About Soligenix, Inc.

Soligenix is a late-stage biopharmaceutical company that strives to develop innovative treatments for rare diseases. Our Specialized BioTherapeutics business segment aims to bring a revolutionary photodynamic therapy called HyBryte™ (SGX301 or synthetic hypericin) to the market as a potential treatment for cutaneous T-cell lymphoma (CTCL). Having already completed a successful Phase 3 study, we are now focusing our efforts on regulatory approval and commercialization activities.

In addition, we are researching the use of synthetic hypericin (SGX302) for psoriasis, our first-in-class innate defense regulator (IDR) technology, dusquetide (SGX942) for inflammatory diseases, and proprietary formulations of oral beclomethasone 17,21-dipropionate (BDP) for the prevention/treatment of gastrointestinal (GI) disorders, such as pediatric Crohn’s disease (SGX203). Together, these potential treatments offer hope for those suffering from rare diseases.

Our Public Health Solutions business segment is actively developing innovative vaccine and therapeutic candidates that are designed to protect people against a variety of infectious diseases. Our RiVax® vaccine candidate is designed to protect against ricin toxin, while SGX943 is a therapeutic candidate for antibiotic-resistant and emerging infectious diseases.

We also have vaccine programs in development that target filoviruses such as Marburg and Ebola, as well as CiVax™, our vaccine candidate for the prevention of COVID-19 caused by SARS-CoV-2.

Our development of these vaccine programs makes use of our proprietary heat stabilization platform technology, ThermoVax®. To date, this business segment has been supported by government grants and contracts from the National Institute of Allergy and Infectious Diseases (NIAID), the Defense Threat Reduction Agency (DTRA), and the Biomedical Advanced Research and Development Authority (BARDA).

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