Fixed High dose Melphalan in treatment of Multiple Myeloma

Multiple Myeloma is a chemotherapy -responsive, but an incurable disease. Standard chemotherapy gives response rate of 50-70% with survival upto 30-40 months.
Studies showed that dose intensification of Melphalan resulted in higher response rates even in patients refractory to standard dose. High dose Melphalan with stem cell transplantation shows higher response rates and longer survival time. Slight non –hematopoetic toxicity is observed.
At a higher dose levels, there are trends towards earlier and deeper mylosuppression.
Despite the slightly prolonged neutropenia, there is not a higher then expected incidence of infections, anorexia, diarrhea, headache or fatigue. No patient required intubations and there is no death reported.
No dose limiting toxicities are observed during treatment.
So the test regimen supplements total body irradiation and allows for administration of approximately 40% higher dose of Melphalan then standard.
The use of bone-seeking radiolabelled isotopes offers several advantages over that of a radiolabelled antibody. It offers a faster clearance from the blood and other organs, less non hematopoetic tissue toxicity. substantially greater doses of radiation can be delivered to hematopoetic tissues as compared to other organs. The toxicity of this supplemental radiation has not been appreciably greater than standard dose.
This approach offers possibility of augmenting antimyeloma therapy without increasing toxicity and improving the response rate and progression free survival. The results of this trial are encouraging.