Clinical Presentation and Outcomes of Patients with Light Chain Amyloidosis Who Have Non-Evaluable Free Light Chains at Diagnosis

Abstract Introduction: Hematologic response criteria for light chain amyloidosis (AL) requires that difference in involved and uninvolved free light chains (dFLC) be at least 5 mg/dL (or 50 mg/L). However, many patients do not meet these criteria and are often excluded from clinical trials. These patients are challenging to follow clinically as organ response takes much longer and therefore response to treatment is difficult to evaluate in the first few cycles. This study aims to evaluate patients who had non-evaluable FLC (dFLC Methods: All patients with newly diagnosed AL seen within 90 days of diagnosis at our institution over a 10-year period (2006-2015) were identified from an institutional database. Data pertaining to demographics, diagnosis, treatment and follow-up was extracted from electronic medical records. Analysis was carried out by chi-square and Fisher's exact test for categorical variables and Kruskal-Wallis and Wilcoxon rank sum test for ordinal and continuous variables. Progression free survival (PFS) is defined as time to progression requiring treatment change or relapse requiring re-institution of treatment or death. PFS and overall survival (OS) were analyzed via the Kaplan-Meier method. Results: Of 1336 patients meeting inclusion criteria, dFLC at diagnosis was known in 1290. 85.4% (n=1101) had dFLC ≥ 5 mg/dL, while 14.6% (n=189) had non-evaluable FLC. Median age at diagnosis (65.2 vs. 63.9 years), gender distribution (males 56.1% vs.64.8%) and involved FLC (lambda: 72.2% vs. 72.9%) was similar in FLC Treatment details are listed in Table 1. ASCT (autologous stem cell transplant) was utilized more commonly in patients with dFLC In patients who had follow up data available, 30.6% (44/144) with dFLC Conclusions: Patients with non-evaluable FLC at diagnosis have significant differences in organ involvement and survival compared to those with FLC ≥ 5 mg/dL at diagnosis. They have less cardiac and liver involvement and a trend towards less GI involvement, which may be secondary to low serum FLC burden and consequent less organ deposition. However, a trend towards higher renal involvement was seen in dFLC Download : Download high-res image (396KB) Download : Download full-size image Download : Download high-res image (126KB) Download : Download full-size image Disclosures Dispenzieri: GSK: Membership on an entity's Board of Directors or advisory committees; Prothena: Membership on an entity's Board of Directors or advisory committees; pfizer: Research Funding; Celgene: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Alnylam: Research Funding; Jannsen: Research Funding. Kapoor: Amgen: Research Funding; Takeda: Research Funding; Celgene: Research Funding. Kumar: Celgene: Consultancy, Research Funding; Janssen: Research Funding; Sanofi: Consultancy, Research Funding; Skyline: Consultancy, Honoraria; BMS: Consultancy; AbbVie: Research Funding; Noxxon: Consultancy, Honoraria; Amgen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding.