Confirmatory Study of Topical HyBryte™ vs. Placebo for the Treatment of CTCL

To evaluate the use of HyBryte, a topical photosensitizing agent, to treat patients with patch/plaque phase cutaneous T-cell lymphoma (mycosis fungoides).

The primary objective of this Phase 3 study is to evaluate the ability of an 18-week course of HyBryte and visible light to induce a Treatment Response in patients with patch/plaque phase CTCL compared to patients receiving placebo and visible light.The study will evaluate the efficacy and safety of HyBryte (0.25% hypericin) gel or placebo gel applied twice weekly for 18 weeks. Treated lesions will be covered with opaque material (such as opaque clothing), followed 21 (±3) hours later by the administration of visible light. All of the participant's lesions that are readily available for exposure to the visible light source will be treated and 3 to 5 index lesions in each patient will be prospectively identified and documented for modified Composite Assessment of Index Lesion Severity (mCAILS) evaluation. Participants will be followed every 4 weeks for a total of 12 weeks following their last light session.