Time to progression was not significantly affected by elevated beta(2)-microglobulin or lactate dehydrogenase levels, advanced age, or cytogenetic abnormalities, but was shorter in patients with albumin < 3 g/dL, Karnofsky performance status < or =70%, bone marrow plasma cell infiltration > or =40%, and, particularly, high plasma cell proliferative activity (> or = 2.5% S-phase cells).