P043 | TRANSPLANT-FREE APPROACHES IN REFRACTORY CLASSICAL HODGKIN LYMPHOMA: A SINGLE CENTRE STUDY

Background. Autologous stem-cell transplantation (ASCT) represents the main approach for refractory classical Hodgkin Lymphoma (HL). Although often curative, this procedure is frequently hindered by short- and long-term toxicities. In recent years, novel drugs such as Checkpoint Inhibitors (CPI), have been introduced for the treatment of relapsed HL, which may also help to achieve a transplant-free cure. Aim. We compared non ASCT approaches (RT with or without CPI maintenance) to salvage chemotherapy and ASCT in patients with HL and a positive end-of-treatment (EoT) PET/CT. Methods. Among the 352 patients with HL treated at the Padua University Hospital since 2004, 37 had a positive EoT PET/CT: 22 received salvage chemotherapy and ASCT (group A), 10 were treated with RT only (group B) and 5 with RT + CPI (group C). Event-Free Survival (EFS) events were defined as disease relapse, start of new therapy and death from any cause. Results. All the patients in group C were females, the median age at diagnosis was 22 (18-35) years, 1 (20%) was at stage IV whereas the remaining at stage II. No patient had bulky disease and only 1 (20%) presented B-symptoms. After a median follow-up (mFU) of 24 months, only 1 patient relapsed and proceeded to third line chemotherapy + ASCT, with a 24-month Overall Survival (OS) of 100% and a 24-month EFS of 67% (30-100). Group B and A exhibited a 24-month OS of 100% and 90% (79-100), with a 24-month EFS of 70% (47-100) and 59% (42-84), respectively. In detail, in group B, with a mFU time of 39 months 4 (40%) patients relapsed and 2 (20%) died, whereas in the group A, after a mFU time of 64 months, 10 (45%) subjects relapsed and 3 (14%) died, including 2 patients who died without experiencing a relapse (1 acute myeloid leukemia). Comparing the survival statistics between groups, no differences in EFS [HR 1.8 (0.2-17) for C vs B and HR 0.4 (0.05-3) for C vs A] and OS (p>0.9 for both analyses) were observed. Discussion. On balance, the RT plus CPI rescue approach proved to be effective in patients with HL and a positive EoT PET/CT with only 1 subject out of 5 relapsing, and no significant differences in survival against the conventional approaches. Although this work suffers from a limited number of patients as well as the short median follow-up time, this treatment may cure a fraction of R/R HL patients sparing them of ASCT, therefore warranting further investigation from prospective trials.