Therapeutic Results in Patients with Hodgkin's Lymphoma Treated with Brentuximab Vedotin — Bulgarian Experience

Background: The introduction of Brentuximab Vedotin (BV) into clinical practice has improved the prognosis and survival of patients with Hodgkin's lymphoma, relapsed after stem cell transplantation or primary refractory disease. Aim: In patients with Hodgkin's lymphoma treated with Brentuximab Vedotin (BV), the overall response rate (ORR), type of response, event free survival (EFS) and the prognostic factors affecting them are analyzed. Patients and methods: Fourty-four (44) Hodgkin lymphoma patients treated with BV in 5 hematology clinics in Bulgaria were studied. The male / female ratio is 1.1 / 1, the mean age is 39.98 +/- 12.48. The most common histological variant is nodular sclerosis 31 (70.5%). In the II clinical stage there were 13 patients (29.5%), III - 16 (36.4%), IV -15 (34.1%). B-symptoms had 36 patients (81.8%), extranodal involvement - 17 (15.9%) and large mediastinal tumor mass - 14 (31.8%). All patients before treatment with BV received 4 (2-12) treatment lines, 50.0% -3 lines, 27.3% - 4 lines, and 9.1% > / = 5 lines. Stem cell transplantation was performed in 33 patients (75.0%), two of which were two autologous STCs, and in one auto/ allo SCT. Results: ORR is 60.0% (N=24) - complete response was achieved in 10 (25.0%) and partial in 14 (35.0%) patients. Stable disease was registered in 7 (17.5%) and progression in 9 (20,5%). Patients achieving at least a partial therapeutic response prior to commencement of BV treatment significantly improved their response at the end of treatment: 15 (62.5%) versus 9 (37.5%) with previous progression and stable disease (P < 0.05, R = + 0.496). PFS for the entire group is 10 months. The median survival (MS) was not reached by the end of the study. Age, sex, histological variant, clinical stage, number, type and outcome of previous treatment lines did not affect the duration of PFS. The only significant prognostic factor that determines a remarkably longer remission is the qualitative therapeutic response: in the CR + PR group, the median PFS is not reached by the time of the analysis, while in patients with stable disease and progression EFS is 7 months (P <0.001). Conclusion: BV is an effective drug with manageable toxicity. The results of the treatment of our patients confirm the accumulated international experience. An additional therapeutic response and prolonged progression-free survival give a chance to these previously doomed patients with Hodgkin's lymphoma.