> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Soligenix Gets ‘Refuse-to File’ Letter on HyBryte
- URL: https://www.fdaweb.com/soligenix-gets-refuse-to-file-letter-on-hybryte/
- Published: 2023-02-14T12:00:00.000Z
- Updated: 2026-09-14T18:15:55.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5153771

FDA has issued Soligenix a refuse-to-file letter for its HyBryte (synthetic hypericin) NDA that is seeking an indication for treating early stage cutaneous T-cell lymphoma. The letter says the NDA, which was submitted 12/14/2022, was not sufficiently complete to allow the review. The company says it is reviewing the letter to determine its next steps, which could include requesting a Type A meeting with the agency to clarify and respond to the issues.

Soligenix describes HyBryte as a novel, first-in-class, photodynamic therapy that is topically applied to skin lesions that is taken up by the malignant T-cells, and then activated by visible light 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,” it says. “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.”