VTD consolidation, without bisphosphonates, reduces bone resorption and is associated with a very low incidence of skeletal-related events in myeloma patients post ASCT

Abstract

We prospectively evaluated the effect of bortezomib, thalidomide and dexamethasone (VTD) consolidation on bone metabolism of 42 myeloma patients who underwent an autologous stem cell transplantation (ASCT). VTD started on day 100 post ASCT; patients received four cycles of VTD (first block), were followed without treatment for 100 days and then received another four VTD cycles (second block). During this 12-month period, bisphosphonates were not administered. Best response included stringent complete remission (sCR) in 15 (35.7%) patients, complete response (CR) in 13 (30.9%), vgPR in 7 (16.6%), PR in 4 (9.5%), while 3 (7.1%) patients developed a progressive disease (PD). Importantly, 33.3% and 47.6% of patients improved their status of response after the first and second VTD block, respectively. VTD consolidation resulted in a significant reduction of circulating C-terminal cross-linking telopeptide of collagen type I (CTX), soluble receptor activator of the nuclear factor-kappa B ligand (sRANKL) and osteocalcin (OC), whereas bone-specific alkaline phosphatase (bALP) remained stable compared with pre-VTD values. During the study period, only one patient with a PD developed a skeletal-related event (that is, radiation to bone). The median time to progression (TTP) after ASCT was 34 months and the median time of next treatment was 40 months. We conclude that VTD consolidation post ASCT reduces bone resorption and is associated with a very low incidence of skeletal-related events (SREs) despite the absence of bisphosphonates; the later do not appear to be necessary in this context. © 2014 Macmillan Publishers Limited.