A Phase II Trial of Teclistamab in Participants With Previously Treated Immunoglobulin Light-chain (AL) Amyloidosis

Inclusion Criteria: * Histologic diagnosis of AL amyloidosis and typed with immunohistochemistry/ immunofluorescence, immunoelectron microscopy, or mass spectrometry. In patients with biopsy-confirmed amyloidosis, ambiguous amyloid typing results, and cardiac involvement alone, a negative pyrophosphate (PYP) or technetium-99m (99mTc) and 3,3-diphosphono-1,2-propanodicarboxylic acid (DPD-Tc99m) bone scan is required to distinguish cardiac involvement due to AL amyloidosis from amyloid transthyretin (ATTR) amyloidosis. Data from the initial diagnosis are accepted. * Genetic testing must be negative for transthyretin mutations associated with hereditary amyloidosis, or immunohistochemistry/ immunofluorescence/ immunoelectron microscopy/ mass spectrometry of amyloid deposits must provide clear evidence of κ or λ light chains in patients who present with peripheral neuropathy or heart as the dominant organ involvement. Data from the initial diagnosis are accepted. * Eastern Cooperative Oncology Group (ECOG) performance status 0,1 or 2 * Mayo stage I-IIIA cardiac disease at Screening * Relapsed patients must have received at least 1 line of treatment, including Dara and bortezomib. Patients must have received at least two cycles of therapy. However, patients who have received high-dose therapy with melphalan as their only therapy are also eligible. * Measurable hematologic disease: a dFLC \>20 mg/L with an abnormal κ/λ ratio (with Freelite® test kits, The Binding Site) or presence…