The Anti-Myeloma Effect Of Bortezomib Is Associated With Osteoblastic Activity.

Myeloma bone disease is characterized by osteolytic destruction associated with suppressed osteoblastic activity possibly through inhibition of the WNT signaling pathway. We already reported the association between increased alkaline phosphatase (ALP) and B but not dexamethasone response in myeloma patients (Zangari et al., BJH 2005, in press). To extend these observations, using data from the large APEX study, we have attempted to assess the relationship between quantitative alkaline phosphatase (ALP) changes during therapy with B and response and time to progression. We were interested in what threshold of increase in ALP (even within the normal laboratory range) might predict efficacy.