Bortezomib and dexamethasone consolidation following risk-adapted melphalan and stem cell transplantation for patients with newly diagnosed light-chain amyloidosis.

To improve the efficacy of risk-adapted melphalan (MEL) in patients with amyloidosis (AL), we conducted a phase II trial using bortezomib and dexamethasone (BD) as consolidation. Forty untreated patients with renal (70%), cardiac (65%), liver/gastrointestinal (15%) or nervous system (13%) AL were assigned MEL 100, 140 or 200 mg/m(2) based on age, renal function and cardiac involvement. Hematological response was assessed at 3 months post stem cell transplant (SCT); patients with less than complete hematological response (CR) received BD consolidation. Four patients with advanced cardiac AL died within 100 days of SCT (10% treatment-related mortality). Survival at 12 and 24 months post treatment start was 88 and 82% overall and was 81 and 72% in patients with cardiac AL. At 3 months post SCT, 45% had ≥ partial response (PR) including 27% CR. Twenty-three patients received consolidation and in 86% response improved; all patients responded in one cycle. At 12 and 24 months, 79 and 60% had ≥ PR, 58 and 40% CR. Organ responses occurred in 55 and 70% at 12 and 24 months. Eight patients relapsed/progressed. One patient with serologic progression had organ impairment at time of progression. In newly diagnosed AL, BD following SCT rapidly and effectively improves responses resulting in high CR rates and maintained organ improvement.

Cancer-testis antigen expression and immunogenicity in AL amyloidosis.

Light-chain amyloidosis (AL) is a plasma cell dyscrasia closely related to multiple myeloma. In multiple myeloma, the cancer-testis antigens (CTAs) CT7 (MAGE-C1), CT10 (MAGE-C2) and MAGE-A CTAs are expressed in up to 80% of cases. In this study, we investigated the expression and immunogenicity of several CTAs in patients with AL amyloidosis in a total of 38 bone marrow specimens by employing standard immunohistochemistry techniques on paraffin-embedded archival tissues. Plasma samples from 35 patients (27 with matched bone marrow samples) were also analyzed by ELISA for sero reactivity to a group of full-length CTA proteins. CT7 was present in 25/38 (66%) while CT10 was demonstrated in 3/38 and GAGE in 1/38 AL amyloid cases. The expression pattern was mostly focal. There were no significant differences with regard to organ involvement, response to treatment, or prognosis in CTA positive compared to negative cases. None of the specimens showed spontaneous humoral immunity to CT7, but sero reactivity was observed in individual patients to other CTAs. This study identifies CT7 as the prevalent CTA in plasma cells of patients with AL amyloidosis. Further analyses determining the biology of CTAs in AL amyloidosis and their value as potential targets for immunotherapy are warranted.