Treatment of Amyloidosis

Diagnostic Confirmation

The American College of Cardiology recommends obtaining tissue biopsy with Congo red staining showing characteristic apple-green birefringence under polarized light 1
Mass spectrometry (LC-MS/MS) is the gold standard for amyloid typing with 88% sensitivity and 96% specificity 1, 2
Complete monoclonal protein screening with all three tests simultaneously: serum free light chain assay (sFLC), serum immunofixation electrophoresis (SIFE), and urine immunofixation electrophoresis (UIFE) 1, 2
The National Comprehensive Cancer Network recommends never relying on standard protein electrophoresis (SPEP/UPEP) alone due to inadequate sensitivity, as it misses monoclonal spikes in nearly 50% of cases 3, 2

For both ASCT-eligible and ASCT-ineligible patients, Daratumumab-CyBorD (daratumumab plus cyclophosphamide, bortezomib, and dexamethasone) is the preferred first-line treatment, achieving very good partial response or better in 78.5% of patients 2
High-dose melphalan (140-200 mg/m²) followed by autologous stem cell transplantation is an alternative for highly selected patients, which achieved 40% complete hematologic remission and improved 5-year survival in 394 patients 3, 2
For patients aged 60-65 years with serum creatinine ≥2 mg/dL, reduce melphalan dose to 100 mg/m² and proceed with extreme caution 2

Tafamidis (VYNDAQEL/VYNDAMAX) is FDA-approved and indicated for treatment of ATTR cardiomyopathy in adults with NYHA Class I-III symptoms to reduce cardiovascular mortality and cardiovascular-related hospitalization 2

Response is assessed at 3-6 months using difference between involved and uninvolved free light chains (dFLC) 1, 4
Complete response (CR): Negative SIFE and UIFE, plus normal FLC ratio 4
Very good partial response (VGPR): dFLC <40 mg/L 4
Partial response (PR): dFLC decrease ≥50% 4
No response (NR): dFLC decrease <50% 4
Organ-specific response is generally observed 6-12 months after hematologic response 1
Cardiac: NT-proBNP decrease >30% and <300 ng/L (if baseline >650 ng/L) 4, 1
Renal: ≥30% decrease in proteinuria or drop below 0.5 g/24 h without ≥25% decrease in eGFR 4
Hepatic: 50% decrease in alkaline phosphatase or ≥2 cm decrease in liver size 4

Effective treatment requires mandatory collaboration between hematologist, cardiologist, nephrologist, gastroenterologist, neurologist, and transplant specialists 2

Common diagnostic errors include delayed diagnosis due to nonspecific symptoms and missing cardiac involvement, which drives prognosis and mortality 2, 5
Treatment errors include using standard heart failure medications in amyloid heart disease and failing to achieve deep hematologic responses, which correlate with improved organ function and survival 2

The primary goal is to eradicate pathological plasma cells and remove amyloidogenic light chains from circulation 2
Cardiac involvement is the main driver of disease prognosis and mortality 2
Deep hematologic responses directly correlate with improved organ function and survival 2