Efficacy of Extracorporeal Photopheresis (ECP) Monotherapy in the Treatment of Cutaneous T Cell Lymphoma.
Authors: Geskin Larisa , Foss Francine , Duvic Madeleine , Straus David , Horwitz Steven , Zain Jasmine , Kuzel Timothy , Querfeld Christiane , Campbell Kim , Knobler Robert 
Published: April 2020

Abstract
Background: Mycosis Fungoides (MF) and its leukemic variant Sezary syndrome (SS) are disorders of malignant, skin homing helper/memory T-cells. MF presents with patches, plaques, or tumors, while SS presents with generalized erythroderma and blood involvement. Either can involve lymph nodes, blood, and viscera. A multi-center, open label, single arm clinical trial previously demonstrated the safety and efficacy of ECP as a monotherapy in the treatment of patients with advanced/refractory MF/SS (Edelson, et al, 1987, N Engl J Med, 316:297–303). The primary endpoint of this study was a ≥25% improvement in skin score maintained for at least 4 weeks. We present a long-term, secondary analysis of these patients to further evaluate clinical outcomes and predictors of response for ECP as a monotherapy in MF/SS. Partial (≥50%) and complete (≥90%) skin score responses, extent of skin disease, number of ECP treatments administered, and the time required to achieve 50% and 90% improvement in skin involvement were evaluated.
Patients and Methods: Thirty-nine patients (pts) who met eligibility criteria were included in the secondary efficacy analysis as the intent-to-treat (ITT) patient population. Thirty-one pts with generalized erythroderma (GE) and 8 pts with extensive patch plaque (EPP) were treated with ECP on 2 consecutive days every 4–5 weeks for 3 months. No concomitant systemic medications for MF/SS were allowed on study; however, topical steroids could be applied to the hands and feet. Patients had received an average of 3.7 (range 0–13) prior therapies (systemic and topical). Immediately prior to undergoing ECP, all pts received oral doses of methoxsalen in order to achieve blood level concentrations ≥50 ng/mL. Skin improvement was calculated by comparing baseline skin score to skin scores on all subsequent treatment dates. The mean baseline skin score of the 39 ITT patients was 262 (median = 291) based on a maximum possible skin score of 400 points.
Results: The median follow-up of the 39 ITT pts was approximately 4 years (range 9 days–7.8 years). Twenty-nine pts (74%) achieved at least a ≥50% improvement in skin score, and 16 pts (41%) achieved ≥90% improvement on ECP monotherapy. The type and extent of skin disease (GE vs. EPP) prior to the start of treatment did not predict response. Patients received a median of 12 (range 4–65) or 30.0 (range 12–109) individual ECP treatments to achieve a ≥50% or ≥90% response, respectively. The mean times to reach a ≥50% or ≥90% response were 8.4 ± 6 months (median=6.5) or 25.2 ±14.9 mos (median=19.6), respectively. The mean duration of a ≥50% response was 32.5 ± 28.6 mos, which included a median of 20 (range 0–153) ECP treatments. Median survival from date of diagnosis and from date of first ECP treatment was 10.6 yrs and 5.4 yrs, respectively.
Conclusions: In this long-term, follow-up analysis, ECP monotherapy was associated with a significant and durable improvement in skin score in the majority of patients with MF/SS.