Use of simple hematological, biochemical and clinical parameters to monitor response of multiple myeloma patients on high dose thalidomide therapy

Abstract

Evidence of increased bone marrow vascularity in multiple myeloma (MM) has led to the use of anti-angiogenic drugs especially thalidomide in relapsed or refractory patients. Currently, parameters such as serum/ urine electrophoresis for M (monoclonal) proteins, bone marrow biopsy with touch preparation and b2 microglobulin are routinely used to assess response to therapy. These investigations are expensive, invasive and require high technical setup. To correlate simple and routine hematological and biochemical parameters with the key marker of disease i.e. M proteins. This is an open label, uncontrolled, single-arm study. Twenty nine refractory or relapsed multiple myeloma patients of both sexes (M=20, F=9) with age ranging between 35-72 years were initiated on 200 mg/day of thalidomide with fortnightly increments of 200 mg to a maximum tolerated dose not exceeding 800 mg/day. All hematological and biochemical parameters were monitored at monthly intervals for one year. Correlation analysis was performed between hemoglobin (Hb), total leukocyte count (TLC), absolute neutrophil count (ANC), platelet count (PC), total proteins (TP), serum albumin and serum globulin on one hand and M protein levels on the other using Pearsons Correlation test by SPSS version 7.5. Hb, TLC, ANC, PC and serum albumin levels showed a significant negative correlation with M proteins. A highly significant positive correlation existed between M proteins on one hand and TP and globulin levels on the other. Dryness of skin indicated positive response to therapy. These correlations were found to be significant at the end of one month of therapy in all the above-mentioned parameters except in TLC where it was significant after 2 months of thalidomide therapy. Results suggest that sustained efficacy of thalidomide therapy may be amenable to monitoring by these simple, inexpensive and easily available investigations after ascertaining an initial response by M protein and marrow plasmacytosis as these parameters closely follow M protein levels. However more studies are required to further substantiate these findings.