Soligenix Announces HyBryte™ Clinical Summary Published in "Expert Opinion on Investigational Drugs"

Rhea-AI Summary

Soligenix (Nasdaq: SNGX) announced a clinical summary of HyBryte™ (synthetic hypericin) for early-stage cutaneous T-cell lymphoma published in Expert Opinion on Investigational Drugs on March 19, 2026. The review highlights HyBryte™'s reported safety, non-mutagenic mechanism, activity on thicker plaques and folliculotropic variants, and comparably improved tolerability versus mechlorethamine.

The company said it is completing patient enrollment in the confirmatory FLASH2 Phase 3 study later in 2026, with an interim analysis expected in 2Q 2026.

Positive

• Peer-reviewed publication summarizes HyBryte™ clinical program
• Reported non-mutagenic mechanism and use of non-carcinogenic light source
• Activity reported on thicker plaque lesions and folliculotropic variants
• FLASH2 Phase 3 enrollment expected complete later in 2026 with interim analysis in 2Q 2026

Negative

• Confirmatory data pending from ongoing FLASH2 Phase 3 study
• No regulatory approval or commercial launch reported in the announcement

Key Figures

FLASH2 Phase 3 enrollment: 66 of 80 patients FLASH2 interim timing: 2Q 2026 Cash balance: $10.5 million +5 more

8 metrics

FLASH2 Phase 3 enrollment 66 of 80 patients HyBryte™ FLASH2 Phase 3 trial as of Feb 10, 2026

FLASH2 interim timing 2Q 2026 Expected interim analysis for HyBryte™ FLASH2 Phase 3

Cash balance $10.5 million Cash as of Q3 2025 reported Feb 12, 2026

Additional NOL funding $0.5 million New Jersey NOL sales program, reported Feb 12, 2026

HyBryte U.S. peak sales >$90 million annually Company estimate for U.S. CTCL market

Global sales potential ≈$2 billion annually Combined HyBryte™, SGX302, SGX945 opportunity from 8-K

Phase 2 trial size 8 patients Open-label SGX945 Behçet’s Disease pilot study

Week 4 improvement 40% vs placebo SGX945 Behçet’s Disease Phase 2a AUC endpoint at Week 4

Market Reality Check

Price: $1.22 Vol: Volume 180,193 is about 1...

normal vol

$1.22 Last Close

Volume Volume 180,193 is about 1.31x the 20-day average of 137,080, indicating elevated trading interest before this news. normal

Technical Shares at $1.22 were trading below the 200-day MA of $1.70 and about 80% under the $6.23 52-week high, but above the $1.02 52-week low.

Peers on Argus

SNGX was down 3.17% pre-news while peers were mixed: LPTX up 238.84%, MBIO down ...

SNGX was down 3.17% pre-news while peers were mixed: LPTX up 238.84%, MBIO down 1.42%, MBRX down 3.70%, SNSE up 0.26%, XTLB down 2.14%. Moves do not point to a unified sector trend.

Historical Context

5 past events · Latest: Mar 10 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Mar 10	Regulatory designation	Positive	+2.5%	UK PIM designation for SGX945 in Behçet's Disease supports future access pathway.
Feb 26	Orphan opinion EU	Positive	-2.5%	EMA committee issued positive orphan opinion for SGX945 in Behçet's Disease.
Feb 24	Investor conference	Positive	+4.5%	Announcement of corporate presentation at BIO Investment & Growth Summit.
Feb 12	Pipeline update	Positive	-1.9%	Update on FLASH2 enrollment, timelines, and cash position plus HyBryte™ estimates.
Dec 18	Clinical data publication	Positive	+0.0%	Publication of positive Phase 2a SGX945 Behçet’s Disease results in Rheumatology.

Pattern Detected

Recent news has been mostly positive, but price reactions have been mixed, with both advances and pullbacks following favorable clinical and regulatory milestones.

Recent Company History

Over the last six months, Soligenix highlighted multiple pipeline advances. On Dec 18, 2025 it reported positive Phase 2a SGX945 data in Behçet’s Disease. On Feb 12, 2026 it detailed progress, including 66 of 80 FLASH2 Phase 3 patients enrolled and cash of about $10.5M. Later in February, SGX945 received a positive EMA orphan opinion with potential 10 years EU exclusivity. On Mar 10, 2026 SGX945 gained UK PIM designation. Today’s HyBryte™ clinical summary publication fits this pattern of external validation of its rare-disease programs.

Market Pulse Summary

This announcement highlights peer-reviewed consolidation of HyBryte™ clinical data in early-stage CT...

Analysis

This announcement highlights peer-reviewed consolidation of HyBryte™ clinical data in early-stage CTCL, emphasizing safety, non-mutagenic mechanism, and efficacy across variants such as folliculotropic mycosis fungoides. It complements prior disclosures that FLASH2 Phase 3 had enrolled 66 of 80 patients and targets an interim analysis in 2Q 2026. Investors may focus on Phase 3 outcomes, cash resources of about $10.5M, and the company’s previously outlined HyBryte™ peak sales expectations as key forward-looking reference points.

Key Terms

cutaneous t-cell lymphoma, photodynamic therapy, phase 3 study

3 terms

cutaneous t-cell lymphoma medical

"HyBryte™ (synthetic hypericin) as a treatment for cutaneous T-cell lymphoma (CTCL)"

Cutaneous T-cell lymphoma is a rare type of skin cancer that develops when certain immune system cells grow uncontrollably, causing skin patches, rashes, or tumors. While it primarily affects health, its rarity and complexity can influence medical research funding and pharmaceutical development, which may impact investment opportunities in healthcare and biotech sectors. Understanding such diseases helps investors gauge potential risks and innovations in medical treatments.

photodynamic therapy medical

"Topical Hypericin: A Promising Photodynamic Therapy for Early-Stage Cutaneous T-Cell Lymphoma"

Photodynamic therapy is a medical treatment that uses a special light-sensitive substance and a specific type of light to target and destroy abnormal or diseased cells, often in cancer treatment. It is important to investors because advances in this technology can lead to new, minimally invasive treatment options, potentially expanding healthcare markets and driving growth for biotech companies involved in developing such therapies.

phase 3 study medical

"ongoing confirmatory FLASH2 Phase 3 study, I was honored to be invited"

A phase 3 study is the large-scale clinical trial that tests whether a new drug or medical treatment actually works and is safe in a broad group of patients, typically after earlier smaller tests. Investors watch these studies like a final dress rehearsal because their successful completion is often required for regulatory approval and market access; positive or negative results can sharply change a company’s future sales prospects and stock value.

AI-generated analysis. Not financial advice.

PRINCETON, N.J., March 19, 2026 /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 a summary of all the clinical trials completed to date evaluating HyBryte™ (synthetic hypericin) as a treatment for cutaneous T-cell lymphoma (CTCL) has been published in the peer-reviewed medical journal Expert Opinion on Investigational Drugs. The publication "Topical Hypericin: A Promising Photodynamic Therapy for Early-Stage Cutaneous T-Cell Lymphoma" is authored by Brian Poligone, MD, PhD, the founder and Medical Director of the Rochester Skin Lymphoma Medical Group and the Director of Cancer Biology Research for the Rochester General Hospital Research Institute who has extensive clinical experience evaluating HyBryte™ with his team's participation in four HyBryte™ clinical studies. 

Expert Opinion on Investigational Drugs is an international monthly peer-reviewed journal, evaluating drugs in preclinical and clinical development.  Authors are encouraged to express their Expert Opinion of the status of the research under review and its impact on clinical practice, rather than simply review the available data.  The audience consists of scientists, managers and decision-makers in the pharmaceutical industry, and others closely involved in research and development.

"Topical synthetic hypericin represents a paradigm shift in the skin-directed management of early-stage CTCL. Its unique mechanism, excellent safety profile, and robust clinical efficacy position it as a formidable potential new agent in the therapeutic armamentarium," stated Dr. Poligone, Director of the Rochester Skin Lymphoma Medical Group. "Following the positive results from the previous Phase 2 and 3 studies I participated in, as well as the ongoing confirmatory FLASH2 Phase 3 study, I was honored to be invited by Expert Opinion on Investigational Drugs to provide a definitive analysis of the HyBryte™ clinical data landscape. HyBryte™ has been demonstrated to have a non-mutagenic mechanism of action, uses a non-carcinogenic light source and appears to have improved tolerability relative to available therapies such as mechlorethamine. The rapid response rates and the efficacy demonstrated on thicker plaque lesions, combined with its activity in difficult to treat disease variants like folliculotropic mycosis fungoides, makes HyBryte™ a potential broad-spectrum, first-line option for patients with early-stage CTCL. We look forward to continuing our support of Soligenix in the development of HyBryte™."

"We are pleased to have Dr. Poligone and his team review the compelling data generated from the HyBryte™ clinical program, enabling the medical community to evaluate its safety, efficacy and utility in early-stage CTCL," stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix.  "We look forward to continuing our work with Dr. Poligone and all our principal investigators as we move towards completing patient enrollment in the FLASH2 Phase 3 study later this year, with an interim analysis of this study expected in 2Q 2026."

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 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 modified Composite Assessment of Index Lesion Severity [mCAILS] 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<0.0001 vs the placebo treatment rate in Cycle 1). Comparison of the 12-week and 6-week treatment responses also revealed a statistically significant improvement (p<0.0001) between the two timepoints, indicating that continued treatment results in better outcomes. HyBryte™ continued to be safe and well tolerated. Additional analyses also indicated that HyBryte™ is equally effective in treating both plaque (response 42%, p<0.0001 relative to placebo treatment in Cycle 1) and patch (response 37%, p=0.0009 relative to placebo treatment in Cycle 1) lesions of CTCL, a particularly relevant finding given the historical difficulty in treating plaque lesions.

The third (optional) treatment cycle (Cycle 3) was focused on safety and all patients could elect to receive HyBryte™ treatment of all their lesions. Of note, 66% of patients elected to continue with this optional compassionate use / safety cycle of the study. Of the subset of patients that received HyBryte™ throughout all 3 cycles of treatment, 49% of them demonstrated a positive treatment response (p<0.0001 vs patients receiving placebo in Cycle 1). Moreover, in a subset of patients evaluated in this cycle, it was demonstrated that HyBryte™ is not systemically available, consistent with the general safety of this topical product observed to date. At the end of Cycle 3, HyBryte™ continued to be well tolerated despite extended and increased use of the product to treat multiple lesions.

Overall safety of HyBryte™ is a critical attribute of this treatment and was monitored throughout the three treatment cycles (Cycles 1, 2 and 3) and the 6-month follow-up period. HyBryte's™ mechanism of action is not associated with DNA damage, making it a safer alternative than currently available therapies, all of which are associated with significant, and sometimes fatal, side effects. Predominantly these include the risk of melanoma and other malignancies, as well as the risk of significant skin damage and premature skin aging. Currently available treatments are only approved in the context of previous treatment failure with other modalities and there is no approved front-line therapy available. Within this landscape, treatment of CTCL is strongly motivated by the safety risk of each product. HyBryte™ potentially represents the safest available efficacious treatment for CTCL. With very limited systemic absorption, a compound that is not mutagenic and a light source that is not carcinogenic, there is no evidence to date of any potential safety issues.

Following the first Phase 3 study of HyBryte™ for the treatment of CTCL, the FDA and the EMA indicated that they would require a second successful Phase 3 trial to support marketing approval. With agreement from the EMA on the key design components, the second, confirmatory study, called FLASH2, has successfully achieved its first safety review milestone with a pre-specified, blinded interim analysis expected to be completed in 2Q2026. This study is a randomized, double-blind, placebo-controlled, multicenter study that will enroll approximately 80 subjects with early-stage CTCL. The FLASH2 study replicates the double-blind, placebo-controlled design used in the first successful Phase 3 FLASH study that consisted of three 6-week treatment cycles (18 weeks total), with the primary efficacy assessment occurring at the end of the initial 6-week double-blind, placebo-controlled treatment cycle (Cycle 1). However, this second study extends the double-blind, placebo-controlled assessment to 18 weeks of continuous treatment (no "between-Cycle" treatment breaks) with the primary endpoint assessment occurring at the end of the 18-week timepoint. In the first Phase 3 study, a treatment response of 49% (p<0.0001 vs patients receiving placebo in Cycle 1) was observed in patients completing 18 weeks (3 cycles) of therapy. In this second study, all important clinical study design components remain the same as in the first FLASH study, including the primary endpoint and key inclusion-exclusion criteria. The extended treatment for a continuous 18 weeks in a single cycle is expected to statistically demonstrate HyBryte's™ increased effect over a more prolonged, "real world" treatment course. Given the extensive engagement with the CTCL community, the esteemed Medical Advisory Board and the previous trial experience with this disease, accelerated enrollment in support of this study is anticipated, including the potential to enroll previously identified and treated HyBryte™ patients from the FLASH study. Discussions with the FDA on an appropriate study design remain ongoing. While collaborative, the agency has expressed a preference for a longer duration comparative study over a placebo-controlled trial. Given the shorter time to potential commercial revenue and the similar trial design to the first FLASH study afforded by the EMA accepted protocol, this study was initiated. At the same time, discussions with the FDA will continue on potential modifications to the development path to adequately address their feedback.

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).

In addition, the FDA awarded an Orphan Products Development grant to support the investigator-initiated study evaluation of HyBryte™ for expanded treatment in patients with early-stage CTCL, including in the home use setting. The grant, totaling $2.6 million over 4 years, was awarded to the University of Pennsylvania that was a leading enroller in the Phase 3 FLASH study.

About Cutaneous T-Cell Lymphoma (CTCL)

CTCL is a class of non-Hodgkin's lymphoma (NHL), a type of cancer of the white blood cells that are an integral part of the immune system. Unlike most NHLs which generally involve B-cell lymphocytes (involved in producing antibodies), CTCL is caused by an expansion of malignant T-cell lymphocytes (involved in cell-mediated immunity) normally programmed to migrate to the skin. These malignant cells migrate to the skin where they form various lesions, typically beginning as patches and may progress to raised plaques and tumors. Mortality is related to the stage of CTCL, with median survival generally ranging from about 12 years in the early stages to only 2.5 years when the disease has advanced. There is currently no cure for CTCL. Typically, CTCL lesions are treated and regress but usually return either in the same part of the body or in new areas.

CTCL constitutes a rare group of NHLs, occurring in about 4% of the more than 1.7 million individuals living with the disease in the U.S. and Europe (European Union and United Kingdom). It is estimated, based upon review of historic published studies and reports and an interpolation of data on the incidence of CTCL that it affects approximately 31,000 individuals in the U.S. (based on SEER [Surveillance, Epidemiology, and End Results] data, with approximately 3,200 new cases seen annually) and approximately 38,000 individuals in Europe (based on ECIS [European Cancer Information System] prevalence estimates, with approximately 3,800 new cases annually).

About Soligenix, Inc.

Soligenix is a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need. Our Specialized BioTherapeutics business segment is developing and moving toward potential commercialization of HyBryte™ (SGX301 or synthetic hypericin sodium) as a novel photodynamic therapy utilizing safe visible light for the treatment of cutaneous T-cell lymphoma (CTCL). With successful completion of the second Phase 3 study, regulatory approvals will be sought to support potential commercialization worldwide. Development programs in this business segment also include expansion of synthetic hypericin (SGX302) into psoriasis, our first-in-class innate defense regulator (IDR) technology, dusquetide (SGX942) for the treatment of inflammatory diseases, including oral mucositis in head and neck cancer, and (SGX945) in Behçet's Disease.

Our Public Health Solutions business segment includes development programs for RiVax®, our ricin toxin vaccine candidate, as well as our vaccine programs targeting filoviruses (such as Marburg and Ebola) and CiVax™, our vaccine candidate for the prevention of COVID-19 (caused by SARS-CoV-2). The development of our vaccine programs incorporates the use of our proprietary heat stabilization platform technology, known as ThermoVax^®. To date, this business segment has been supported with government grant and contract funding 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).

For further information regarding Soligenix, Inc., please visit the Company's website at https://www.soligenix.com and follow us on LinkedIn and Twitter at @Soligenix_Inc.

This press release may contain forward-looking statements that reflect Soligenix's current expectations about its future results, performance, prospects and opportunities, including but not limited to, potential market sizes, patient populations, clinical trial enrollment. Statements that are not historical facts, such as "anticipates," "estimates," "believes," "hopes," "intends," "plans," "expects," "goal," "may," "suggest," "will," "potential," or similar expressions, are forward-looking statements. These statements are subject to a number of risks, uncertainties and other factors that could cause actual events or results in future periods to differ materially from what is expressed in, or implied by, these statements. Soligenix cannot assure you that it will be able to successfully develop, achieve regulatory approval for or commercialize products based on its technologies, particularly in light of the significant uncertainty inherent in developing therapeutics and vaccines against bioterror threats, conducting preclinical and clinical trials of therapeutics and vaccines, obtaining regulatory approvals and manufacturing therapeutics and vaccines, that product development and commercialization efforts will not be reduced or discontinued due to difficulties or delays in clinical trials or due to lack of progress or positive results from research and development efforts, that it will be able to successfully obtain any further funding to support product development and commercialization efforts, including grants and awards, maintain its existing grants which are subject to performance requirements, enter into any biodefense procurement contracts with the U.S. Government or other countries, that it will be able to compete with larger and better financed competitors in the biotechnology industry, that changes in health care practice, third party reimbursement limitations and Federal and/or state health care reform initiatives will not negatively affect its business, or that the U.S. Congress may not pass any legislation that would provide additional funding for the Project BioShield program. In addition, there can be no assurance as to the timing or success of any of its clinical/preclinical trials. Despite the statistically significant result achieved in the first HyBryte™ (SGX301) Phase 3 clinical trial for the treatment of cutaneous T-cell lymphoma or any other studies (including the open-label, investigator-initiated study) and the overall blinded aggregate response rate observed in the second HyBryte™ (SGX301) Phase 3 clinical trial, there can be no assurance that the second HyBryte™ (SGX301) Phase 3 clinical trial will be successful or that a marketing authorization from the FDA or EMA will be granted. Additionally, although the EMA has agreed to the key design components of the second HyBryte™ (SGX301) Phase 3 clinical trial, no assurance can be given that the Company will be able to modify the development path to adequately address the FDA's concerns or that the FDA will not require a longer duration comparative study. Notwithstanding the result in the first HyBryte™ (SGX301) Phase 3 clinical trial for the treatment of cutaneous T-cell lymphoma and the Phase 2a clinical trial of SGX302 for the treatment of psoriasis, there can be no assurance as to the timing or success of the clinical trials of SGX302 for the treatment of psoriasis. Additionally, despite the biologic activity observed in aphthous ulcers induced by chemotherapy and radiation, there can be no assurance as to the timing or success of the clinical trials of SGX945 for the treatment of Behçet's Disease. Further, there can be no assurance that RiVax^® will qualify for a biodefense Priority Review Voucher (PRV) or that the prior sales of PRVs will be indicative of any potential sales price for a PRV for RiVax^®. Also, no assurance can be provided that the Company will receive or continue to receive non-dilutive government funding from grants and contracts that have been or may be awarded or for which the Company will apply in the future. These and other risk factors are described from time to time in filings with the Securities and Exchange Commission (the "SEC"), including, but not limited to, Soligenix's reports on Forms 10-Q and 10-K. Unless required by law, Soligenix assumes no obligation to update or revise any forward-looking statements as a result of new information or future events.

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SOURCE SOLIGENIX, INC.

FAQ

What did Soligenix (SNGX) announce about HyBryte™ on March 19, 2026?

They announced a peer-reviewed clinical summary of HyBryte™ published in Expert Opinion on Investigational Drugs. According to Soligenix, the article reviews completed HyBryte™ trials, safety profile, and activity in thicker plaques and folliculotropic CTCL variants.

When does Soligenix expect an interim analysis from the FLASH2 Phase 3 study for HyBryte™ (SNGX)?

An interim analysis is expected in 2Q 2026. According to Soligenix, patient enrollment in the confirmatory FLASH2 Phase 3 study is to be completed later in 2026 ahead of that interim look.

What clinical advantages does the HyBryte™ review claim for early-stage CTCL treatment?

The review highlights a non-mutagenic mechanism, non-carcinogenic light use, and reported improved tolerability versus mechlorethamine. According to Soligenix, HyBryte™ also demonstrated rapid responses and efficacy on thicker plaques and difficult variants.

Is HyBryte™ approved for cutaneous T-cell lymphoma following the March 19, 2026 publication?

No, HyBryte™ is not reported as approved in this announcement. According to Soligenix, a confirmatory FLASH2 Phase 3 study is ongoing and key data remain pending before regulatory decisions.

Who authored the HyBryte™ clinical summary published March 19, 2026, and why is it relevant?

The summary was authored by Brian Poligone, MD, PhD, an experienced CTCL clinician and investigator. According to Soligenix, his analysis consolidates results from four HyBryte™ clinical studies and assesses clinical utility for early-stage CTCL.