Mogamulizumab Monotherapy in the Treatment of Relapsed/Refractory Peripheral T-Cell Lymphoma or Cutaneous T-Cell Lymphoma Patients in Single-Institution Experience

Objectives; T-cell lymphomas generally have a poor outcome with shorter long-term survival compared with B-cell lymphomas. CC chemokine receptor 4 (CCR4) is highly expressed by aggressive peripheral T-cell lymphoma, not otherwise specified (PTCLs), particularly adult T-cell leukemia/lymphoma (ATL) and cutaneous T-cell lymphomas (CTCLs). Mogamulizumab is a humanized immunoglobulin G1 monoclonal antibody that targets CCR4. In phase II study, Mogamulizumab has been shown to high clinical efficacy and low toxicity. However, its efficacy has not been well evaluated in the clinical setting. We retrospectively analyzed the efficacy and safety of Mogamulizumab of against relapsed/refractory non- ATL T-cell lymphomas.

Methods; Fourteen patients with relapsed/ refractory CCR4 positive PTCLs or CTCL were treated with weekly Mogamulizumab (1.0 mg/kg) alone at Iwate Prefectural Central Hospital between January 2015 and June 2017. CCR4 expression was determined by immunohistochemistry by a central laboratory center (SRL, Tokyo, Japan). In the first line, most patients receive commonly anthracycline-containing induction chemotherapy regimens such as CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone). The patients had received a median of one previous chemotherapy regime (range 1-3).

We retrospectively evaluated (1) the best overall response, (2) progression-free survival (PFS), (3) overall survival (OS), (4) the best response according to disease site(peripheral blood; PB, lymph nodes; LN and skin) and (5) safety. Response assessments were performed after eighth mogamulizumab infusions according to the 1999 IWG criteria guidelines for response assessments for NHL (IWG-NHL). Treatment efficacy in patients with CTCL was evaluated by using a Global Response Score. Treatment was discontinued if progressive disease (PD) was evident.For safety evaluations, adverse events (AEs) were graded according to the National Cancer Institute Common Terminology Criteria for AEs, version 4.0.

Results; The median age was 69 years old (range 48-85). Eight patients are male. The diagnosis comprised PTCLs (n=12) and CTCL (n=2). The median follow up periods and median number of Mogamulizumab infusion were 293 days (range 49- 681) and 8 courses (range 2- 9). (1) Complete remission (CR) was achieved in two patients (16.7%) and partial remission in one patients (8.3%), stable disease (SD) in two patients (16.7%), respectively. And (2) median PFS was 88 days and (3) median OS was 475 days. Peripheral blood, lymph node and skin lesion were affected in two, ten, and six patients, respectively. (4) In PB, complete response (CR) was obtained in all two patients (100%) and two patients were achieved CR in skin lesion (33.3%). In LN, only one of ten patient manifested CR(10.0%). This patient's tumor burden is low. (5) With regard to safety issues, hematological AEs were frequently observed, and lymphocytopenia occurred in 62.5% of patients. However, the AEs were controllable and tolerated. Non-hematological AEs, including fever, infusion reactions and skin trouble , were frequently observed (37.5%, 25.0%, and 37.5%, respectively). Grade 3/4 non-hematological AEs were scarcely observed.

Conclusions; Although Mogamulizumab monotherapy is effective with highly safety, the patients who had swollen lymph node may need combination chemotherapy with mogamulizumab. The number of patients was small in this retrospective analysis, further investigation are required.