SNGX: Agreement with EMA on Second Confirmatory Trial for HyBryte™

By David Bautz, PhD

Business Update

Reaches Agreement with European Medicines Agency on Second Confirmatory Trial for HyBryte™

On April 3, 2024, Soligenix, Inc. SNGX announced it has reached agreement with the European Medicines Agency (EMA) on the key design elements for a confirmatory Phase 3 trial of HyBryte (synthetic hypericin) for the treatment of cutaneous T cell lymphoma (CTCL).

The proposed Phase 3 FLASH 2 trial will be a randomized, double blind, placebo controlled, multicenter study that will enroll approximately 80 subjects with CTCL. HyBryte will be applied topically to CTCL lesions twice weekly for 18 weeks, with each application followed 21 (± 3) hours later by the administration of visible light at a wavelength of 500 to 650 nm. The light will be administered starting at 6 J/cm² and will be increased upwards by 2 J/cm² until: 1) the patient experiences a Grade 1 erythema; 2) the patient reaches a maximum dose of 30 J/cm², or 3) the patient cannot tolerate the treatment time, whichever comes first. All of the subject's lesions that are readily available to the visible light source will be treated and 3 to 5 index lesions will be prospectively identified and indexed for the modified composite assessment of index lesions severity (mCAILS) evaluation prior to randomization. The primary endpoint will be assessed by the percent of patients in each treatment group (HyBryte or placebo) achieving a Partial or Complete Response of the treated lesions defined as a ≥50% reduction in the total mCAILS score for the 3-5 index lesions following 18 weeks of treatment compared to the total mCAILS score at baseline. Following treatment, subjects will be followed every 4 weeks for a total of 12 weeks (through Week 30). One interim analysis is planned after 60% of the total subjects have completed the primary endpoint evaluation. A sample size recalculation may be performed after examining the assumptions or the trial can be halted for futility, safety concerns, or overwhelming efficacy. The figure below gives a comparison between the proposed FLASH2 trial and the previously completed FLASH trial. The similarities between the two increases our confidence in a successful outcome for the FLASH2 trial.

We anticipate that the trial will begin enrollment prior to the end of 2024 and topline results are expected in the second half of 2026. The company is continuing discussions with the U.S. Food and Drug Administration (FDA) on an appropriate study design as the agency has expressed a preference for a longer duration comparative study over a placebo-controlled trial.

Orphan Drug Designation for Sudan Ebolavirus Vaccine

On April 11, 2024, Soligenix announced that the U.S. FDA has granted orphan drug designation (ODD) to the active ingredient in SuVax™, the subunit protein vaccine of recombinantly expressed Sudan ebolavirus (SUDV) glycoprotein, for "the prevention and post-exposure prophylaxis against SUDV infection".

ODD is designed to assist companies that are developing therapies for rare diseases and disorders, defined as those that affect 200,000 people or fewer in the U.S. Drugs granted ODD receive a seven year term of market exclusivity upon final FDA approval. In addition, financial and regulatory benefits are available including government grants to conduct clinical trials, waiver of FDA user fees, and certain tax credits.

SuVax addresses the potentially lethal Sudan Virus Disease caused by SUDV. While vaccines exist for Zaire ebolavirus, they are ineffective against SUDV. Previous results showed that SuVax offered 100% protection of non-human primates infected with a lethal dose of SUDV. SuVax is based on the company's novel vaccine platform that consists of a robust protein manufacturing process, a nano-emulsion adjuvant that induces a strong immune response, and thermostabilization of the adjuvant and antigen in a single vial that is stable at elevated temperatures for extended timeframes.

Conclusion

We're glad to see that Soligenix is ready to move ahead with the second confirmatory Phase 3 clinical trial of HyBryte and we're confident that the FDA will come to an agreement with the company soon on its preferences for the trial. With a protocol in place for the second Phase 3 study of HyBryte we have increased our probability of approval, which has increased our valuation to $4.00.