FLASH Clinical Trial- Update

Positive results were announced earlier this year for the FLASH Study, a phase 3 clinical trial in CTCL, by Soligenix. SGX301 is a novel first-in-class photodynamic therapy utilizing safe visible light for activation. The active ingredient in SGX301 is synthetic hypericin, a potent photosensitizer that is topically applied to skin lesions, is taken up by the malignant T-cells, and then activated by fluorescent light 16 to 24 hours later. This treatment approach avoids the risk of secondary malignancies (including melanoma) inherent with the frequently employed DNA-damaging chemotherapeutic drugs and other photodynamic therapies that are dependent on ultraviolet exposure. In a published Phase 2 clinical study in CTCL, patients experienced a statistically significant (p=0.04) improvement with topical hypericin treatment in comparison to the placebo. SGX301 has received orphan drug and fast track designations from the US Food and Drug Administration (FDA), as well as orphan designation from the European Medicines Agency (EMA).

The Phase 3 FLASH trial enrolled 169 patients (166 evaluable) with Stage IA, IB or IIA CTCL. The trial consists of three treatment cycles, each of 8 weeks' duration. 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, 116 subjects received SGX301 treatment (0.25% synthetic hypericin) and 50 received placebo treatment of their index lesions. A total of 16% of the patients receiving SGX301 achieved at least a 50% reduction in their lesions (graded using a standard measurement of dermatologic lesions, the CAILS* score) compared to only 4% of patients in the placebo group at 8 weeks (p=0.04) during the first treatment cycle (primary endpoint). SGX301 treatment in the first cycle was safe and well tolerated. 

In the second open-label treatment cycle (Cycle 2), all patients received SGX301 treatment of their index lesions. Data surrounding the Cycle 2 will be released in the coming days. 

In the third (optional) treatment cycle (Cycle 3), all subjects could receive SGX301 treatment of all their lesions. Of note, the majority of patients (~70%) enrolled have elected to continue with this optional cycle of the study. Moreover, in a subset of patients evaluated in this cycle, it was demonstrated that SGX301 is not systemically available, consistent with the general safety of this topical product observed to date. Other secondary measures assessed are treatment response (including duration), degree of improvement, and time to relapse and safety. Results from Cycle 3 and the subsequent 6-month follow-up after completion of treatment will be further announced as the final patients continue to complete their designated visits.  

Overall safety of SGX301 is a critical attribute of this treatment and will continue to be monitored throughout the additional treatment cycles and the 6-month follow-up period. 

The Phase 3 CTCL clinical study was partially funded by the National Cancer Institute via a Phase II SBIR grant (#1R44CA210848-01A1) awarded to 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. For further information regarding Soligenix, Inc., please visit the Company's website at www.soligenix.com.

*The Composite Assessment of Index Lesion Severity CAILS score is obtained by adding the severity score of each of the following categories for up to 5 index lesions: erythema, scaling, plaque elevation, and surface area. Severity is graded from 0 (none) to 8 (severe) for erythema and scaling; 0 to 3 for plaque elevation; and 0 to 9 for surface area.

Reference: Bibliographic reference(s) of the original questionnaire

Duvic M, Martin AG, Kim Y, et al. Phase 2 and 3 clinical trial of oral bexarotene (Targretin capsules) for the treatment of refractory or persistent early-stage cutaneous T-cell lymphoma. Arch Dermatol. 2001;137:581–593 (PubMed abstract)

Olsen EA, et al. Clinical End Points and Response Criteria in Mycosis Fungoides and Sezary Syndrome: A Consensus Statement of the International Society for Cutaneous Lymphomas, the United States Cutaneous Lymphoma Consortium, and the Cutaneous Lymphoma Task Force of the European Organisation for Research and Treatment of Cancer. J Clin Oncol. 2011 Jun 20;29(18):2598-607 (Full text article)