Purpose: Despite the recent success of Bruton's tyrosine kinase (BTK) inhibitors for the treatment of Waldenstrom macroglobulinemia (WM), their indefinite treatment duration ultimately tantamount to substantial financial and emotional burden. On the other hand, fixed duration of proteasome inhibitors (PI) have shown rapid and reasonable response in WM treatment. Despite the well-known synergism between PI and immunomodulatory drugs (IMiD), there is no trials evaluating such combination in WM.
Materials and methods: Based on above, we designed this phase II study to investigate the efficacy and safety of 6 cycles of 28-day bortezomib-thalidomide-dexamethasone (VTD) regimen for treatment-naïve WM.
Results: A total of 15 patients were enrolled: major response rate was 64.3%, and overall response rate was 78.6%. During the median follow-up of 41 months, median progression-free survival (PFS) was 13 months and overall survival 40 months. For responders, median duration of response was 13 months and median PFS 19 months. The most common adverse event (AE) of any grade was constipation (57.1%). The most common grade ≥ 3 AE was anemia (21.4%).
Conclusion: All in all, we hereby provide proof-of-concept that PI + IMiD may be an attractive backbone for fixed duration treatment. It should be noted that granting the same level of access to newer drugs globally is virtually impossible. Thus efforts to develop regimens using readily available drugs to yield similar or adequate treatment outcomes should not be disregarded. In this sense, we believe our study holds its place for its novelty and eloquently addresses achieving the daunting societal quest of health equity.
Keywords: Bortezomib; Frontline; Thalidomide; Waldenstrom macroglobulinemia.