Abstract In a phase 2 trial of panobinostat in 129 patients with relapsed or refractory Hodgkin lymphoma, exploratory analyses of chemokines and cytokines were prospectively performed in 109 patients to determine their association with clinical outcomes. Patients were categorized into two groups (reductions > median and reductions ≤ median) based on percentage change from baseline of log10 transformed measurements. Thymus and activation-regulated chemokine (TARC) was most strongly associated with clinical outcome. Early reduction of TARC was observed in responding patients, with the greatest reduction at cycle 1, day 15 (C1D15). Of 93 patients with C1D15 samples, there were three complete and 25 partial responses. The group with TARC reductions > median at C1D15 had more responders (18 [39%] vs. 10 [21%]), longer progression-free survival (10.6 vs. 4.9 months), shorter time to response and longer overall survival than the group with reductions ≤ median. This study is registered at www.ClinicalTrials.gov , NCT00742027.