The effect of UVA light/8-methoxypsoralen exposure used in Extracorporeal Photopheresis treatment on platelets and extracellular vesicles

Extracorporeal Photopheresis (ECP) is a leukapheresis based treatment for Cutaneous T-Cell Lymphoma, which takes advantage of the cellular lethal effects of UVA light in combination with a photoactivated drug, 8-methoxypsoralen. 25% of patients treated with ECP do not respond to treatment, however the underlying mechanisms for this lack of response remain unknown. Platelets, a rich source of extracellular vesicles (EVs) and key mediators in thromboinflammatory oncological progression, as well as leukocytes, are both processed through ECP and are subsequently transfused back into the patient, delivering potent immunomodulation. The effect of exposing platelets and their EVs directly to Ultra Violet A light (UVA)/8-methoxypsoralen is currently unknown. Platelet-rich plasma (PRP) was isolated from healthy donors and exposed to UVA light and/or 8-methoxysporalen in vitro and platelet activation and aggregation was assessed. EV size and concentration were also characterised by Nanoparticle Tracking Analysis and Flow Cytometry. We found that UVA light and 8-methoxypsoralen treatment in vitro does not induce platelet aggregation or significantly alter levels of the platelet activation markers, soluble P-selectin or platelet factor 4, with circulating levels of small and large EV size and concentration remaining constant. Therefore, utilising the combination of UVA light and 8-methoxypsoralen used in ECP in vitro does not activate platelets or alter important circulating EVs. Further studies will be needed to validate if our observations are consistent in vivo.

Extracorporeal photopheresis and multimodality therapy in patients with T-cell cutaneous lymphomas: Real-life experience in Argentina

BACKGROUND

Extracorporeal photopheresis (ECP) as a part of multimodality therapy, is one of the treatments for Sézary syndrome (SS) and advanced stage mycosis fungoides (MF). This study aims to describe cutaneous and peripheral blood responses of patients with MF and SS who received multimodality therapy.

METHODS

In this cross-sectional retrospective study, patients with MF or SS who received ECP treatment in combination with at least one additional systemic treatment between 2011 and 2018 were included. ECP consisted of a two-session cycle every 2 to 4 weeks. Cutaneous and blood responses were evaluated with updated criteria.

RESULTS

Twenty-eight patients (11 (39%) with MF and 17 (51%) with SS) were included. Their median age at diagnosis was 63 (57-67) years. The median number of treatments before ECP was 2 (1-3). Seven out of 11 patients with MF (63%) underwent an assessment of cutaneous response. Five patients (70%) presented a partial response; 1 (15%), stable disease, and 1 (15%) progressive disease. Thirteen of the 17 patients with SS (76%) underwent evaluation. One patient (8%) presented a complete cutaneous response; 6 (46%), a partial response; 5 (38%), stable disease; and 1 (8%), progressive disease. None of them relapsed during the study period in both groups. No ECP-related adverse effects occurred during the study.

CONCLUSION

Most patients with SS and MF who underwent multimodality therapy with ECP had favorable cutaneous and blood response. It is safe to combine ECP with other treatments. Studies with large numbers of patients are necessary to assess the effects of ECP on patient survival.

The optimal use of bexarotene in cutaneous T-cell lymphoma

The management goal in cutaneous T-cell lymphomas (CTCLs) is to improve symptoms and induce remission. Early-stage disease is generally treated with skin-directed therapies. However, if these do not control the disease, systemic therapy becomes necessary. Bexarotene, a novel rexinoid, is an oral, noncytotoxic drug that has been approved in Europe for the treatment of refractory advanced-stage CTCL and in the U.S.A. for refractory CTCL. We provide guidance on the use of bexarotene in the management of CTCL, based on data from phase II/III clinical trials and the authors' clinical experience, and suggest how the potential of the drug can be maximized. The clinical trial results with bexarotene are reviewed, especially in comparison with interferon-alpha, which is the other commonly used noncytotoxic systemic therapy for CTCL. A treatment algorithm for bexarotene in refractory CTCL is suggested. As bexarotene may take time to achieve a maximum response, this algorithm recommends that therapy should be continued for a sufficient period to allow for a delayed onset of action. In addition, possible combination therapies with bexarotene are discussed. We conclude that bexarotene is effective in the management of CTCL, and has the advantage of oral administration. An on-going randomized clinical trial comparing psoralen plus ultraviolet A (PUVA) with PUVA plus bexarotene will provide valuable information about this combination regimen in early-stage disease, but further data are needed on the relative efficacies of other combination therapies with bexarotene in CTCL.

Immunopathogenesis and therapy of cutaneous T cell lymphoma

Cutaneous T cell lymphomas (CTCLs) are a heterogenous group of lymphoproliferative disorders caused by clonally derived, skin-invasive T cells. Mycosis fungoides (MF) and Sezary syndrome (SS) are the most common types of CTCLs and are characterized by malignant CD4(+)/CLA(+)/CCR4(+) T cells that also lack the usual T cell surface markers CD7 and/or CD26. As MF/SS advances, the clonal dominance of the malignant cells results in the expression of predominantly Th2 cytokines, progressive immune dysregulation in patients, and further tumor cell growth. This review summarizes recent insights into the pathogenesis and immunobiology of MF/SS and how these have shaped current therapeutic approaches, in particular the growing emphasis on enhancement of host antitumor immune responses as the key to successful therapy.