Good Profile of Efficacy/Tolerance of Bortezomib or Idelalisib in Waldenström Macroglobulinemia Associated with Acquired Von Willebrand Syndrome.

Acquired von Willebrand syndrome (AVWS) in the setting of Waldenström macroglobulinemia (WM) is a challenging condition. No real standard of care is recommended for these patients, although the therapeutic strategy should include a rapid approach to the emergency bleeding events and to the underlying malignant lymphoid disorder. We report here our experience treating three elderly patients with these concomitant hematologic entities. The use of a bortezomib-based chemotherapy regimen showed a good profile of tolerance and efficacy even in a long-term follow-up period. These patients were treated for several years before switching their therapy to idelalisib, a targeted oral therapy that inhibits phosphatidylinositol 3-kinase isoform-delta (PI3KD), which is part of the signaling pathway downstream B-cell receptor. This approach was well tolerated and efficacious, although some adverse effects were observed, particularly at hepatic levels, but were all reversible. The same profile of tolerance/efficacy was observed in one very old patient who received idelalisib as a first-line therapy. We think that bortezomib-based therapy could be considered in refractory patients with AVWS associated with WM.