Primary amyloidosis associated with multiple myeloma. Predictors of successful therapy.

Of 34 patients with primary amyloidosis seen at the University of Arizona between 1973 and 1984, 25 had amyloidosis in association with overt multiple myeloma. Response to treatment was evaluable in 16 of the 25 patients. Median survival in the seven patients (44 percent) with response to treatment was 28 months versus a median of seven and a half months for the nine patients without response (p less than 0.001). Although there were no absolute predictors of response, patients with response were much less likely to have cardiac amyloid (14 percent versus 78 percent, p = 0.02), but more likely to have unusually high serum beta 2-microglobulin (above 15 micrograms/dl in three of four with response versus in neither of two without response) and kappa subtype monoclonal protein (57 percent versus 33 percent). Renal amyloid and/or serum creatinine levels above 2 mg/dl in three of seven (43 percent) patients with response did not preclude a good outcome. It is concluded that a chemotherapy induction trial is worthwhile in primary amyloidosis associated with myeloma since a subset of patients can have prolonged survival (more than two years).