PET-adapted therapy after three cycles of ABVD for all stages of Hodgkin lymphoma: results of the GATLA LH-05 trial.

The role of Ann Arbor staging in determining treatment intensity after achieving a negative positron emission tomography (PET) has not been established in classical Hodgkin lymphoma (cHL). Patients with stage I-IV cHL, received three cycles of ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) and an interim PET scan (PET3). PET3-negative patients received no further therapy. PET3-positive patients received three additional cycles of ABVD plus involved-field radiation therapy or salvage chemotherapy, if refractory to ABVD, and were re-evaluated by PET scan (PET6). Study endpoints were 3-year progression-free survival (PFS) and overall survival (OS) rates. Two hundred and thirty-nine patients with early-stage and 138 with advanced-stage were evaluable. Overall, 260 patients (70%) were PET3-negative and had higher 3-year PFS (90% vs. 65%; P < 0·0001) and OS (98% vs. 92%; P = 0·007) rates than PET3-positive patients. All PET3-negative patients, regardless of disease stage at diagnosis, achieved similarly good PFS (90-91%; P = 0·76) and OS (97-99%). The only independent prognostic factor for PFS was PET3-negativity (Hazard ratio 3·8; 95% confidence interval 2·4-6·3; P < 0·0001). This study suggests that cHL patients who achieve a negative PET3 following ABVD have an excellent outcome, regardless of stage at diagnosis. An appropriately powered, phase III trial will be necessary to confirm these findings.