Complete remission rate and outcome after intensive treatment of 177 patients under 75 years of age with IgG myeloma defining a circumscribed diseaseentity with a new staging system

Because the presence of IgG paraprotein in the blood is clear cut, it makes IgG myeloma a more circumscribed disease than myeloma as a whole in which to study treatment efficacy particularly relating to complete remission (CR ). Between May 1989 and December 1997, 177 consecutive patients with IgG myelo ma who were <75 years old were seen, of whom 153 entered a sequential thera py (ST) programme of initial courses of C-VAMP infusional chemotherapy (IC) , high-dose treatment (with or without stem cell rescue) (119 patients) and maintenance interferon (87 patients). 74/153 (48.4%) patients entered CR. Median overall survival (OS) and event- free survival (EFS) were 4.9 and 2.1 years, respectively. Multivariate anal ysis at presentation showed OS was significantly prolonged for beta(2)M <2. 7mg/l and age <median 52, whilst beta(2)M <2.7 mg/l and Hb >8.5 g/dl predic ted for longer EFS. For CR patients, age <median 51 years, absence of Bence -Jones proteinuria (BJP), male sex and white blood cells (WBC) <7 x 10(9)/l predicted for a longer OS. Longer length of first CR was predicted by abse nce of BJP at presentation (P = 0.03) and fewer than five courses of IC (P = 0.02) to attain CR. We have therefore been able to refine the use of ST in IgG myeloma, redefin e CR as a 'macro' endpoint, and propose a new staging system for IgG myelom as. Analysis of 41 comparable IgA patients showed IgG to be a distinct enti ty.