No abstract

response in PV with limited toxicity [1]. The ability of Pegasys to induce complete molecular responses suggests selective targeting of the malignant clone [2]. Earlier clinical studies have likewise demonstrated a beneficial effect in early stage B-CLL using nonpegylated interferon alpha 2a [3]. The diagnosis of concomitant CLL/MPN is a rare event and in a recent study analysis of prognostic markers for CLL demonstrated that in patients with a coexistent MPN, lymphoproliferative disorders follow a clinically indolent course [4,5].Our patient has achieved a substantial hematologic, molecular and splenic response in his PV after 22 months on low dose Pegasys. Moreover, he has achieved a favorable reduction in the B-cell CLL clonal population and a change in Zap-70 status from indeterminate to negative.As far as we know, this is the first report of treatment of concomitant PV and chronic lymphocytic leukemia with Pegasys and the first to demonstrate a positive therapeutic effect on both disorders.