ANTI-MYELOMA ACTIVITY OF PAMIDRONATE IN-VIVO

Two patients with progressive myeloma were treated with pamidronate di sodium every 2-4 weeks. Pamidronate therapy resulted in a significant reduction of marrow plasmacytosis and plasma cell labelling index (PCL I), together with durable (greater than or equal to 20 months) stabili zation of immunoglobulin (Ig) levels and an increase in bone mineral d ensity in the first patient and >50% reduction in Ig levels and bone m arrow plasmacytosis in the second. This, to our knowledge, is the firs t report of an anti-myeloma effect of bisphosphonates in humans and pr ovides evidence that a therapeutic intervention largely directed at th e myeloma microenvironment may alter the natural history of the diseas e.