Real-world study on the use of pegylated interferon alpha-2a for treatment of mycosis fungoides/Sézary syndrome using Time to Next Treatment as a measure of clinical benefit: An EORTC CLTG study.

ABSTRACT

INTRODUCTION: Mycosis fungoides (MF) and Sézary syndrome (SS) are chronic malignant diseases that typically necessitate diverse strategies to achieve remission. Systemic interferon alpha (IFN-α, subtypes 2a and 2b) has been used for MF/SS since 1984, however its production was recently stopped and so the recombinant pegylated (PEG) form of IFN α-2a remains as single IFN alternative treatment, even though not approved for MF/SS. OBJECTIVE: To assess effectiveness and safety of PEG IFN α-2a in monotherapy and in combination with other treatments using time to next treatment (TTNT) as a measure of clinical therapeutic benefit in real world setting. METHODS: We conducted an international and multicenter retrospective study of patients with MF and SS at any stage, treated with PEG IFN α-2a, from July 2012 to February 2022. Patients were included across 11 centers in 10 countries. Primary endpoints were to determine TTNT of PEG IFN α-2a and the adverse events (AE) in MF/SS. RESULTS: In total 105 patients were included, mean age was 61 (22-86 years); 42 (40%) with disease stage IA-IIA, 63 (60%) with stage IIB-IVB. PEG IFN α-2a was combined with other therapies in 67 (64%) patients, usually with extracorporeal photopheresis (36%) and bexarotene (22%). Fifty-seven percent of stage I-IIA patients achieved ORR, whereas 51% of stage IIB-IVB. Combination therapy showed a TTNT of 10.4 months, while 7 months in monotherapy (p=0.0099). Overall, TTNT was 9.2 months, ORR was 53% (56/105), CR and PR were 13% and 40%, respectively.AE were described in 69% (72) of the patients. Flu-like symptoms (27%), lymphopenia (23%) and elevated liver function (10%) were the most frequently reported. Grade 3-4 adverse events were reported in 23 (21%) patients, which were mostly related to myelosuppression. LIMITATIONS: retrospective data analysis and unrestricted number of combination therapies. CONCLUSIONS: PEG IFN α-2a for MF/SS showed ORR of 53%, TTNT of 9.2 months, superiority of combination regimens in comparison to monotherapy and doses of 180 mcg/weekly related to higher ORR.