New treatments for adult T-cell leukemia/lymphoma

Adult T cell leukemia lymphoma (ATL) is a mature T cell neoplasm caused by human T-cell lymphotropic virus type 1 (HTLV-1). ATL is endemic in specific geographic regions of the world closely related to areas with high prevalence of HLTV-1 infection, including Southwestern Japan, the Caribbean Basin, Central Africa, South America, Northern and Central Australia. HLTV-1 is primarily transmitted through breastmilk in asymptomatic carriers with a long latency period before transformation into ATL in 3 - 5 % of carriers after acquisition of multiple leukemogenic mutations. The Shimoyama classification established by the Japanese Lymphoma Study Group more than three decades ago remains clinically relevant and practical for guiding treatment. Due to the rarity of this illness, prospective, large prospective clinical are challenging to perform and treatment recommendations are based upon limited evidence. Aggressive disease subtypes have median survival ranging in months and the only curative therapy remains achieving deep remission with induction therapy followed by consolidative allogeneic transplantation. The prognosis for relapsed disease remains dismal due to chemo-refractoriness and limited therapeutic options. Herein, we review the current landscape of novel therapeutic agents with a focus on relapsed and refractory ATL including their mechanisms of action, resistance, and clinical efficacy.