An Australian Amyloidosis Network analysis of Australian patients with immunoglobulin light chain amyloidosis treated with bortezomib-based chemotherapy.

BACKGROUND

Immunoglobulin light chain (AL) amyloidosis is a rare but devastating monoclonal gammopathy where organ failure develops secondary to tissue deposition of misfolded immunoglobulin light chains.

AIMS: We aimed to describe the characteristics and outcomes of a uniformly treated cohort of Australian patients with AL amyloidosis.

METHODS

Subjects required a histological diagnosis of AL amyloidosis, symptomatic organ involvement and initial treatment with a bortezomib-based regimen. Kaplan-Meier survival analysis was performed and the impact of baseline variables on response was assessed using Cox regression testing.

RESULTS

Of 271 patients with AL amyloidosis, median age was 66 years and 53% were male. Seventy-five per cent of cases were lambda restricted, 79% had cardiac involvement and 64% had renal involvement. Overall haematological response rate was 82% being complete in 31% and very good partial response in 36%. Eight per cent of patients died prior to response assessment. Median overall survival was 74 months with inferior overall survival independently associated with more advanced cardiac disease (P = 0.022 for cardiac stage IIIA and P < 0.0001 for stage IIIB), age (P = 0.016) and autonomic neuropathy (P = 0.003). A 6-month landmark analysis demonstrated a significant impact of the depth of haematologic response on overall survival.

CONCLUSIONS

We provide the first description of a large cohort of Australian patients with AL amyloidosis. Two-thirds of patients achieve deep haematological responses with bortezomib-based therapy. We confirm the major impact of the severity of cardiac involvement on survival in AL amyloidosis, with stage IIIB disease portending a particularly poor outcome.