The present invention relates to novel polymer conjugates of polypeptide variants of the HMGB1 high affinity binding domain Box-A (HMGB1 Box-A) or of a biologically active fragment of HMGB1 Box-A. Further, the invention relates to novel polymer conjugates of polypeptide variants of the HMGB1 high affinity binding domain Box-A (HMGB1 Box-A). Moreover, the present invention concerns the use of said polymer conjugates of polypeptide molecules of HMGB1 Box-A to diagnose, prevent, alleviate and/or treat pathologies associated with extracellular HMGB1 and/or associated with an increased expression of RAGE.