Efficacy and Safety of Topical Hypericin Photodynamic Therapy for Early-Stage Cutaneous T-Cell Lymphoma (Mycosis Fungoides): The FLASH Phase 3 Randomized Clinical Trial.

Importance: Given that mycosis fungoides-cutaneous T-cell lymphoma (MF/CTCL) is chronic, there is a need for additional therapies with minimal short- and long-term adverse effects. Topical synthetic hypericin ointment, 0.25%, activated with visible light is a novel, nonmutagenic photodynamic therapy (PDT). Objectives: To determine the efficacy and safety of topical synthetic hypericin ointment, 0.25%, activated with visible light as a nonmutagenic PDT in early-stage MF/CTCL. Design, Settings, and Participants: This was a multicenter, placebo-controlled, double-blinded, phase 3 randomized clinical trial (FLASH study) conducted from December 2015 to November 2020 at 39 academic and community-based US medical centers. Participants were adults (≥18 years) with early-stage (IA-IIA) MF/CTCL. Interventions: In cycle 1, patients were randomized 2:1 to receive hypericin or placebo to 3 index lesions twice weekly for 6 weeks. In cycle 2, all patients received the active drug for 6 weeks to index lesions. In cycle 3 (optional), both index and additional lesions received active drug for 6 weeks. Main Outcomes and Measures: The primary end point was index lesion response rate (ILRR), defined as 50% or greater improvement in modified Composite Assessment of Index Lesion Severity (mCAILS) score from baseline after 6 weeks of therapy for cycle 1. For cycles 2 and 3, open label response rates were secondary end points. Adverse events (AEs) were assessed at each treatment visit, after each cycle, and then monthly for 6 months. Data analyses were performed on December 21, 2020. Results: The study population comprised 169 patients (mean [SD] age, 58.4 [16.0] years; 96 [57.8%] men; 120 [72.3%] White individuals) with early-stage MF/CTCL. After 6 weeks of treatment, hypericin PDT was more effective than placebo (cycle 1 ILRR, 16% vs 4%; P = .04). The ILRR increased to 40% in patients who received 2 cycles of hypericin PDT (P < .001 vs cycle 1 hypericin) and to 49% after 3 cycles (P < .001 vs cycle 1 hypericin). Significant clinical responses were observed in both patch and plaque type lesions and were similar regardless of age, sex, race, stage IA vs IB, time since diagnosis, and number of prior therapies. The most common treatment-related AEs were mild local skin (13.5%-17.3% across cycles 1-3 vs 10.5% for placebo in cycle 1) and application-site reactions (3.2%-6.9% across cycles 1-3 vs 4% for placebo in cycle 1). No drug-related serious AEs occurred. Conclusion and Relevance: The findings of this randomized clinical trial indicate that synthetic hypericin PDT is effective in early-stage patch and plaque MF/CTCL and has a favorable safety profile. Trial Registration: ClinicalTrials.gov Identifier: NCT02448381.

Characterization of a partial-body irradiation model with oral cavity shielding in nonhuman primates.

Purpose: Characterization of a novel partial-body irradiation (PBI) shielding strategy in nonhuman primates (NHP; rhesus macaques), aimed at protecting the oral cavity, with respect to various gastrointestinal acute radiation syndrome (GI-ARS) syndrome parameters as well as buccal ulceration development.Materials and methods: NHPs were irradiated using a Cobalt-60 gamma source, in a single uniform dose, ranging from 9-13 Gy and delivered at 0.60-0.80 Gy min-1. Animals were either partially shielded via oral cavity shielding (PBIOS) or underwent total-body irradiation (TBI).Results: Clinical manifestations of GI-ARS, and also radiation-induced hematology and clinical chemistry changes, following PBIOS were comparable to the PBI NHP GI-ARS model utilizing shielding of the distal pelvic limbs and were significantly milder than TBI at similar radiation doses. Nadir citrulline levels were comparable between PBIOS and TBI but signs of recovery appeared earlier in PBIOS-treated animals. The PBIOS model prevented oral mucositis, whereas the TBI model presented buccal ulcerations at all tested radiation dose levels.Conclusions: Taken together, these results suggest that the PBIOS model is a suitable alternative to traditional PBI. For GI-ARS investigations requiring orally administered medical countermeasures, PBIOS confers added value due to the prevention of oral mucositis over traditional PBI.