Seeking light-chain amyloidosis very early: The SAVE trial—identifying clonal lambda light chain genes in patients with MGUS or smoldering multiple myeloma.

Authors

null

Ping Zhou

Tufts Medical Center, Boston, MA

Ping Zhou , Adin Kugelmass , Denis Toskic , Amandeep Godara , Teresa Fogaren , Cindy Varga , Ray Comenzo

Organizations

Tufts Medical Center, Boston, MA, Tufts Medical Center - Cancer Center, Boston, MA, Division of Hematology/Oncology, John C. Davis Myeloma and Amyloid Program, Tufts Medical Center, Boston, MA

Research Funding

Other

Background: In systemic AL amyloidosis (AL), caused by clonal Ig free light chains (LC) produced in 75% of cases by λ clones, patients often present with advanced organ damage, making earlier diagnosis a critical unmet need. Five λIGLV germline genes account for 75% of AL λ-type (IGLV 6-57, 1-44, 2-14, 1-51, 3-1) (Blood 2017;129:299), representing 56% of all AL patients. Relative risk of AL versus MM with these clonal genes can be high (7.3, 6-57; 2.5, 1-44), intermediate (1.7, 2-14; 1.2, 1-51) or low (0.8, 3-1) (Amyloid 2009;16:1). Progression to AL from smoldering multiple myeloma (SMM) or monoclonal gammopathy of undetermined significance (MGUS) occurs but is not well appreciated (JCO 2014; 32:2679). SAVE is a trial for λ SMM or λ MGUS patients with a κ:λ FLC ratio < 0.26 and difference between involved and uninvolved FLC > 23mg/L (JCO 2014;32:2699). Methods: Eligible patients ship peripheral blood (PB) or bone marrow (BM) samples to us for RT-PCR with cDNA from CD138+ cells, using primers for the Vλ families (Blood 2001;98:714). Amplicons are sequenced and the IGLV germline genes identified in IMGT (ImMunoGene-Tics, www.imgt.org). If the germline gene is AL-related, further evaluation is pursued. Results: Twenty asymptomatic λ patients from 18 states have been enrolled (3M, 17F) and 23 PB and 4 BM specimens obtained. Medians of months from diagnosis, involved FLC, κ:λ ratios, MNC and CD138-selected cells were 20.5 months, 113mg/L, κ:λ 0.06, 8.1x106 (0.8-24) and 3x105 (0-30), respectively. Seventeen patients have had IGLV genes identified, 12 with the first and 5 with additional specimens including 4 BM. Increased risk of AL was identified in 7 patients, 2 of whom had undiagnosed AL (both with IGLV2-14 germline genes). One patient with SMM diagnosed in 2016 had AL λ-type with GI involvement and is 9 months status post MEL 200 stem cell transplant (SCT), and the second with SMM diagnosed in 2009 had cardiac AL λ-type by heart biopsy with an NT-proBNP 171 (but with a suggestive MRI) and is en route to SCT. Conclusions: The SAVE trial enables early diagnosis of AL λ-type based on the λIGLV gene used by the clonal plasma cells. By RT-PCR in this pilot study we identified the clonal λ gene 85% of the time. Earlier diagnosis will enable treatment with effective therapy such as MEL 200 SCT. Clinical trial information: NCT02741999

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Abstract Details

Meeting

2019 ASCO Annual Meeting

Session Type

Poster Discussion Session

Session Title

Hematologic Malignancies—Plasma Cell Dyscrasia

Track

Hematologic Malignancies—Plasma Cell Dyscrasia

Sub Track

Plasma Cell Disorders

Clinical Trial Registration Number

NCT02741999

Citation

J Clin Oncol 37, 2019 (suppl; abstr 8010)

DOI

10.1200/JCO.2019.37.15_suppl.8010

Abstract #

8010

Poster Bd #

336

Abstract Disclosures