Key Points CyBorD achieves excellent outcome in noncardiac patients with AL amyloidosis and can rescue subjects with reversible heart damage. The outcome of high-risk patients remains poor, but response to CyBorD can also improve survival in this group.

Amyloidosis is a disorder caused by misfolding of autologous protein and its extracellular deposition as fibrils, resulting in vital organ dysfunction and eventually death. Pulmonary amyloidosis may be localised or part of systemic amyloidosis.Pulmonary interstitial amyloidosis is symptomatic only if the amyloid deposits severely affect gas exchange alveolar structure, thus resulting in serious respiratory impairment. Localised parenchymal involvement may be present as nodular amyloidosis or as amyloid deposits associated with localised lymphomas. Finally, tracheobronchial amyloidosis, which is usually not associated with evident clonal proliferation, may result in airway stenosis.Because the treatment options for amyloidosis are dependent on the fibril protein type, the workup of all new cases should include accurate determination of the amyloid protein. Most cases are asymptomatic and need only a careful follow-up. Diffuse alveolar-septal amyloidosis is treated according to the underlying systemic amyloidosis. Nodular pulmonary amyloidosis is usually localised, conservative excision is usually curative and the long-term prognosis is excellent. Tracheobronchial amyloidosis is usually treated with bronchoscopic interventions or external beam radiation therapy.

Oral melphalan and dexamethasone (MDex) is a standard treatment for patients with AL amyloidosis who are not eligible for stem cell transplantation at many referral centers. However, following encouraging reports on the activity of bortezomib combined with alkylators and dexamethasone, these combinations are being moved to frontline therapy. We compared the outcome of 87 patients treated with bortezomib plus MDex (BMDex) with that of 87 controls treated with MDex. Patients and controls were matched for age, cardiac and renal function and free light chain burden. A higher rate of complete responses was observed with BMDex (42 vs 19%), but this did not result in a survival improvement in the overall population. However, a significant survival advantage for BMDex was observed in patients without severe (New York Heart Association class III or IV) heart failure and with N-terminal pro-natriuretic peptide type-B <8500 ng/l. Patients treated with full-dose dexamethasone had similar response rates and survival whether they received bortezomib or not. Intermediate-risk patients who are not fit enough to receive high-dose dexamethasone are likely to take the greatest advantage from the addition of bortezomib to MDex.

The validated criteria of hematologic response in light-chain (AL) amyloidosis are based on the measurement of circulating free light chains (FLCs). Patients with a difference between involved and uninvolved FLC (dFLC) <50 mg/L cannot be assessed for response and are excluded from clinical trials. We compared the clinical characteristics and outcome of 203 newly diagnosed patients with dFLC <50 mg/L (low dFLC) with 866 patients with measurable dFLC (high dFLC) evaluated between 2004 and 2015. Heart involvement was significantly less common and less advanced in the low-dFLC group (43% vs 83% and Mayo stage III 45% vs 15%, both < .001), whereas renal involvement was more frequent (77% vs 63%, < .001) and more severe (renal stage III 26% vs 18%, = .001). Overall survival (OS) was significantly better in the low-dFLC group (median 117 vs 21 months, < .001), whereas no difference was seen in renal survival (RS). Within each Mayo stage, patients with low dFLC had a longer survival. In the low-dFLC group, complete response was associated with a significant advantage in OS (median not reached vs 117 months, = .005) and with a better RS. A reduction in dFLC after therapy of<10 mg/L was associated with a better OS and RS in patients with at least a dFLC >20 mg/L baseline. Nineteen percent of newly diagnosed patients with AL amyloidosis have low dFLC and had a better outcome. Hematologic response assessed with adapted criteria predicts OS and RS in these patients, who can thus be assessed for response and included in clinical trials with appropriate stratification.