Achievement of complete response (CR) before autologous stem cell transplantation (ASCT) is one of the main predictive factors of outcome in patients (pts) affected by relapsed/refractory (R/R) classical Hodgkin Lymphoma (cHL) eligible to high-dose chemotherapy. The predictive role of interim PET during salvage treatment has not been investigated in pts receiving BEGEV (Bendamustine, Gemcitabine and Vinorelbine) as first salvage treatment. With the aim to investigate the predictive value of PET after 2 cycles of BEGEV (PET2) in terms of CR rate and survival in pts who completed 4 BEGEV courses followed by ASCT, we retrospectively collected data of 90 consecutive R/R cHL pts eligible to ASCT treated from 2011 to 2021 in 3 Italian centres. Eleven out of 90 pts were excluded due to BEGEV discontinuation for progressive disease (PD) before or at PET2. Seventy-nine pts who completed the planned 4 BEGEV cycles were analysed: median age at relapse was 37 years (range: 18-70), 39 pts (49%) were in stage III-IV, 13 pts (16%) had B symptoms and 23 pts (29%) had extranodal involvement (EI). Thirty-eight pts (48%) were primary refractory, 21 pts (27%) had an early and 20 pts (25%) a late relapse. PET2 was negative [Deauville Score (DS) 1-3] in 61 (77%) and positive in 18 pts (23%) (DS 4 in 15 pts, DS 5 in 3 pts). Adverse risk factors at relapse (EI, B symptoms and time to relapse) did not correlate with PET2 positivity. At evaluation after 4 BEGEV cycles, CR was achieved in 62 (78%), partial response in 6 (8%) and PD in 11 (14%) pts. Complete response after 4 BEGEV was obtained in 55/61 (90%) PET2 negative pts and 7/18 (39%) PET2 positive pts (OR=14.4, 95% CI 3.8-45.2, p<0.0001). Autologous SCT was performed in 73 pts, following BEGEV in 59 pts (75%) and after further salvage treatments in 14 pts (18%). With a median follow-up of 36 (range: 5-100) months, 3-years overall survival (OS), progression-free survival (PFS) and event-free survival (EFS) for the whole study population were 93%, 72% and 63%. No significant differences in OS and PFS were detected according to PET2 result. Conversely, 3-years EFS was significantly superior in PET2 negative vs PET2 positive pts [71% vs 32%, OR 13.66 (95% CI 3.4-62.1) p<0.0001] (Fig.1). In conclusion, R/R cHL pts with PET2 positive during BEGEV salvage treatment had a significantly inferior probability to achieve CR after 2 additional BEGEV cycles and could benefit from early exposure to new therapeutic strategies before ASCT.