Treatment of AL-amyloidosis with dexamethasone plus alpha interferon.

Current therapy for primary systemic (AL) amyloidosis has only modest efficacy (response rate 25%) and because it includes alkylating agents, it has a significant leukemogenic potential (actuarial risk 21% at 3.5 years). We treated 9 consecutive patients with biopsy proven AL amyloidosis seen at our institution with pulse dexamethasone induction (40 mg on days 1-4, 9-12, 17-20 repeated q 35 days) for 3-6 cycles followed by maintenance alpha interferon 3-6 million units thrice weekly. Three patients also received maintenance dexamethasone (40 mg/day x 4 days q 4-8 weeks) for the first year. Improvement in > or = 1 AL organ involvement was seen in 8 of 9 patients. Of 7 patients with nephrotic range proteinuria, 6 had > or = 50% reduction in nonspecific proteinuria with a median time to response of 4 months (range 3-9 months). Marked improvement in organ function was also seen in 4 patients with gastrointestinal, hepatic and neuropathic involvement. However, none of the 2 patients with congestive heart failure improved. This dexamethasone plus alpha interferon regimen, devoid of leukemogenic potential, may lead to rapid and durable improvement in organ function in a significant proportion of patients with AL amyloidosis and deserves further evaluation as front line therapy.