Pamidronate has been shown to reduce skeletal complications and prolong survival. Thalidomide has produced responses and substantial remissions, even for patients with chemotherapy-resistant disease. Despite the higher response rates and improved survival associated with HDC and ASCT, most of these patients with MM will relapse and die of recurrent disease.
Relapses occur mainly due to regrowth of resistant myeloma cells.
Although higher doses of chemotherapy or radiation would potentially eradicate resistant MM cells for patients, this approach is not practical because current HDC regimens are already at the limits of tolerance. Technology that would target drugs or radiation to major sites of disease while sparing nontarget tissues could potentially be more effective and could avoid many of the toxicities associated with damage to nontarget tissues. The bulk of MM cells reside in bone and bone marrow cavities. Diphosphonate chelates, injected intravenously, are taken up exclusively in trabecular bone that is being remodeled. No infusion-related toxicities were observed.