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SGX301 (synthetic hypericin)

Phase 3

Cutaneous T-Cell Lymphoma | Small molecule | Dermatology |Soligenix, Inc.|Last Updated: Aug 13, 2026

Target and mechanism

ModalitySmall molecule

Also known as Hypericin, SGX301

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLED
Total Trials1
Total Enrollment169

FDA Designations

No designations recorded

Clinical trial landscape

SGX301 (synthetic hypericin) · 5 trials · 7 indications

Phase 3 1Phase 2 4
NCT02448381FLASH [Fluorescent Light Activated Synthetic Hypericin] Clinical Study: Topical SGX301 (Synthetic Hypericin) for the Treatment of Cutaneous T-Cell Lymphoma (Mycosis Fungoides)Cutaneous T-Cell Lymphoma
COMPLETED169 Analytics
PHASE3COMPLETED
FLASH [Fluorescent Light Activated Synthetic Hypericin] Clinical Study: Topical SGX301 (Synthetic Hypericin) for the Treatment of Cutaneous T-Cell Lymphoma (Mycosis Fungoides)
Cutaneous T-Cell LymphomaUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of Responders and Non-Responders With a Treatment Response in 3 Treated Lesions as Defined as a ≥50% Improvement in the Composite Assessment of Index Lesion Disease Severity (CAILS) Score When Compared to Patients Receiving Placebo
8 weeks

The percentage of patients achieving a treatment response in each of the 2 treatment groups. A treatment response was defined as a ≥50% improvement in CAILS score at Week 8 when compared to the CAILS score at baseline. The Composite Assessment of Index Lesion Disease Severity (CAILS) score measures: Erythema (or redness) on a scale of 0 (no redness) to 8 (very red), Scaling on a scale of 0 (no scaling) to 8 (all of the lesion is covered by a very rough surface), Plaque Elevation on a scale of 0 (no evidence of plaque above normal skin level) to 3 (plaque shows marked elevation above normal skin level) and Surface Area on a scale of 0 (no lesion/surface area is 0 cm\^2) to 18 (the lesion is larger than 300 cm\^2). A lower score means a better outcome. The overall CAILS score was calculated by adding the total score as described above for each of the 3 lesions. The overall CAILS score has a range of 0 to 111. A lower score means a better outcome.

Number of Treatment Responses of Index Lesions
Baseline up to 54 weeks

A Treatment Response is defined as a ≥50% improvement in the Composite Assessment of Index Lesion Severity (CAILS) score score at each evaluation timepoint (every 6 weeks up to 54 weeks) when compared to the CAILS score at baseline. The CAILS score measures: Erythema (or redness) on a scale of 0 (no redness) to 8 (very red), Scaling on a scale of 0 (no scaling) to 8 (all of the lesion is covered by a very rough surface), Plaque Elevation on a scale of 0 (no evidence of plaque above normal skin level) to 3 (plaque shows marked elevation above normal skin level) and Surface Area on a scale of 0 (no lesion/surface area is 0 cm\^2) to 18 (the lesion is larger than 300 cm\^2). A lower score means a better outcome. The overall CAILS score is calculated by adding the total score as described above for each of the 3-5 index lesions. A lower score means a better outcome.

Number of Participants With a Treatment Response in the Modified Composite Assessment of Index Lesion Disease Severity (mCAILS) Score
12 weeks

A treatment response is defined as a ≥50% improvement in mCAILS score at Week 12 when compared to the mCAILS score at baseline. The Modified Composite Assessment of Index Lesion Disease Severity (mCAILS) score measures: Erythema (or redness) on a scale of 0 (no redness) to 8 (very red), Scaling on a scale of 0 (no scaling) to 8 (all of the lesion is covered by a very rough surface), Plaque Elevation on a scale of 0 (no evidence of plaque above normal skin level) to 3 (plaque shows marked elevation above normal skin level) and Surface Area on a scale of 0 (no lesion/surface area is 0 cm\^2) to 18 (the lesion is larger than 300 cm\^2). A lower score means a better outcome.

Number of patients that achieve a 0 or 1 score using the 5-point Investigator's Global Assessment scale
18 weeks

The percentage of patients in each treatment group that achieve a 0 or 1 score (Clear or Almost Clear) evaluation using the 5-point Investigator's Global Assessment (IGA) scale. The 5-point IGA scale: * Score 0: Clear - No signs of psoriasis; post-inflammatory hyperpigmentation may be present * Score 1: Almost Clear - No thickening; normal to pink coloration; no to minimal focal scaling * Score 2: Mild - Just detectable to mild thickening; pink to light red coloration; predominantly fine scaling * Score 3: Moderate - Clear distinguishable to moderate thickening; dull to bright red; moderate scaling * Score 4: Severe - Severe thickening with hard edges; bright to deep red coloration; severe/coarse scaling covering almost all lesions

Electrocardiograms (ECG)
10 weeks

Assess any ECG QT interval changes (defined as any occurrences of QT interval \>500 ms or changes in QT interval \>60 ms) during standard HyBryte photodynamic therapy.

Systemic Blood Levels
10 weeks

Assess the systemic blood levels of hypericin during standard HyBryte photodynamic therapy.

Secondary Endpoints

Number of Responders and Non-Responders With a Treatment Response in 3 Treated Lesions as Measured by the Composite Assessment of Index Lesion Disease Severity (CAILS) Score (Cycle 1 and 2 SGX301 vs Cycle 1 Placebo)
16 weeks
Number of Responders and Non-Responders With a Treatment Response of 3 Treated Lesions as Measured by the Composite Assessment of Index Lesion Disease Severity (CAILS) Score in Patients Who Received 3 Cycles of SGX301
24 weeks
Patch Lesion Response Rates With Extended Treatment (Cycle 1 & 2 SGX301 vs Cycle 1 Placebo)
16 weeks
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
SGX301ACTIVE_COMPARATORThree treatment cycles, each six (6) weeks followed by a two (2) week rest period. Treatment uses 0.25% SGX301 in USP Hydrophilic Ointment (or placebo) applied twice per week followed by fluorescent light therapy. Cycle 1: Patients randomized 2:1 to active/placebo will have three (3) index lesions treated and evaluated. Cycle 2: All patients will have three (3) index lesions treated and evaluated with active SGX301 ointment. Cycle 3: All patients will be given the opportunity to enter an open-label cycle of active SGX301 ointment treatment for all lesions (index and non-index).
PlaceboPLACEBO_COMPARATORPlacebo ointment is indistinguishable from ointment containing active SGX301 and is only used in Cycle 1. Treatment paradigm (ointment application and fluorescent light therapy) is identical.
HyBryte (0.25 % Hypericin) with Visible LightEXPERIMENTALHyBryte (0.25 % hypericin) ointment will be applied to CTCL lesions and treated with visible light 24 (±6) hours later starting at 5 J/cm\^2. Drug application/light sessions will be done twice a week (at least 2 calendar days apart) for up to 54 weeks.
HyBryte (0.25 % hypericin)EXPERIMENTALHyBryte (0.25 % hypericin) ointment will be applied to CTCL lesions and treated with visible light 18-24 hours later starting at 6 J/cm\^2. Drug application/light session will be done twice a week (at least 2 calendar days apart) for 12 weeks.
Valchlor (mechlorethamine)ACTIVE_COMPARATORValchlor (0.016% mechlorethamine) gel will be applied to CTCL lesions once daily for 12 weeks.
Cohort 1 - SGX302 Ointment (0.25 % Hypericin)EXPERIMENTALSGX302 (0.25 % hypericin) ointment will be applied to lesions and treated with visible light 24±6 hours later starting at 5 J/cm\^2 with a gradual escalation of light therapy up to 25 J/cm\^2. Drug application/light session will be done twice a week (at least 2 calendar days apart) for 18 weeks.
Cohort 2 - SGX302 Ointment (0.25 % Hypericin)EXPERIMENTALSGX302 (0.25 % hypericin) ointment will be applied to lesions and treated with visible light 24±6 hours later starting at 5 J/cm\^2 with a faster escalation of light therapy up to 25 J/cm\^2. Drug application/light session will be done twice a week (at least 2 calendar days apart) for 18 weeks.
Cohort 3 - SGX302 Gel (0.25 % Hypericin)EXPERIMENTALSGX302 (0.25 % hypericin) gel will be applied to lesions and treated with visible light 24±6 hours later starting at 5 J/cm\^2 with a faster escalation of light therapy up to 40 J/cm\^2. Drug application/light session will be done twice a week (at least 2 calendar days apart) for 18 weeks.

Interventions

NameTypeDescription
SGX301 (synthetic hypericin)DRUG0.25% SGX301 in USP Hydrophilic Ointment applied twice per week, covered by opaque bandage for 12-24 hours, then treated with an initial dose of 5 J/cm\^2 fluorescent light.
PlaceboDRUGUSP Hydrophilic Ointment applied twice per week, covered by opaque bandage for 12-24 hours, then treated with an initial dose of 5 J/cm\^2 fluorescent light.
HypericinDRUGHyBryte is synthetic hypericin formulated as a 0.25% hypericin ointment
Visible LightOTHERAfter application of HyBryte (0.25% hypericin ointment), participants will be placed in a light booth containing fluorescent light bulbs to activate the HyBryte.
Mechlorethamine Topical GelDRUGValchlor is an FDA-approved drug for the treatment of CTCL.
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites33

Inclusion Criteria: * Subjects must have a clinical diagnosis of CTCL (mycosis fungoides), Stage IA, Stage IB, or Stage IIA. * Subjects must have a minimum of three (3) evaluable, discrete lesions. * Subjects must be willing to refrain from sunbathing for the duration of the study. Exclusion Crite...

Countries:United States
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Competitive Landscape -Cutaneous T-Cell Lymphoma 3 trials

Top 1 of 2 competitors

CompanyTickerTrialsLead PhaseDrugs
Incyte CorporationINCY2PHASE2Ruxolitinib
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Recent Changes (Last 90 Days)

MEDIUMSep 13, 2026NCT05442190TRIAL_REMOVED: changed
MEDIUMSep 13, 2026NCT05442190TRIAL_REMOVED: changed

Frequently asked questions about SGX301 (synthetic hypericin)

What is SGX301 (synthetic hypericin) used for?

SGX301 is being developed for the treatment of cutaneous T-cell lymphoma, including mycosis fungoides, a type of skin lymphoma. It is also being studied in a related program for mild-to-moderate psoriasis. The drug is applied topically and is intended for skin-directed therapy in these dermatologic conditions.

Who makes SGX301?

SGX301 is developed by Soligenix, Inc., a biopharmaceutical company that trades on the Nasdaq under the ticker symbol SNGX. Soligenix is responsible for the clinical development of the synthetic hypericin product for cutaneous T-cell lymphoma and related dermatology indications.

What phase is SGX301 in?

SGX301 is in Phase 2 clinical development. The completed trials include a Phase 2 study of HyBryte (synthetic hypericin) versus Valchlor in cutaneous T-cell lymphoma and a Phase 2 study of hypericin ointment with visible light for mycosis fungoides. It is investigational and has not been approved by the FDA.

What clinical trials is SGX301 in?

SGX301 has been evaluated in completed Phase 2 trials, including NCT06149247 comparing HyBryte to Valchlor in CTCL, NCT05872854 testing hypericin ointment with visible light in mycosis fungoides, NCT05442190 for topical SGX302 in psoriasis, and NCT05380635 assessing pharmacokinetics and ECG effects after eight weeks of HyBryte treatment.

Is SGX301 the same as hypericin?

SGX301 is a synthetic formulation of hypericin, and the terms are often used interchangeably. Hypericin is the active ingredient, while SGX301 refers to the specific synthetic version developed by Soligenix for topical use in cutaneous T-cell lymphoma and other skin conditions.