Systemic immunoglobulin light-chain amyloidosis is characterized by pathologic deposition of immunoglobulin light chains as amyloid fibrils in vital organs, leading to organ impairment and eventual death. That the process is reversible was evidenced in an in vivo experimental model in which fibril-reactive chimeric monoclonal antibody (mAb) 11-1F4 directly targeted human light-chain amyloid deposits and affected their removal via a phagocyte-mediated response. To determine the tolerability and potential amyloidolytic effect of this agent (now designated mAb CAEL-101), we conducted a phase 1a/b study involving 27 patients, most of whom had manifestations of organ involvement. This was an open-label study in which phase 1a patients received mAb CAEL-101 as a single intravenous infusion with escalating dose levels from 0.5 mg/m2 to 500 mg/m2 to establish the maximum tolerated dose (MTD). In phase 1b, the antibody was administered as a graded series of 4 weekly infusions. For both phases, there were no drug-related serious adverse events or dose-limiting toxicities among recipients, and the MTD was not reached. The majority of patients had deep hematologic responses but persistent organ disease prior to treatment. Fifteen of 24 patients (63%) who manifested cardiac, renal, hepatic, gastrointestinal, or soft tissue involvement had a therapeutic response to mAb CAEL-101 as evidenced by serum biomarkers or objective imaging modalities with a median time to response of 3 weeks. Infusions of mAb CAEL-101 were well tolerated and, for the majority, resulted in improved organ function, notably for those with cardiac impairment. This trial was registered at www.clinicaltrials.gov as #NCT02245867.

(2017). Interim analysis of the phase 1a/b study of chimeric fibril-reactive monoclonal antibody 11-1F4 in patients with AL amyloidosis. Amyloid: Vol. 24, PROCEEDINGS OF THE XVth INTERNATIONAL SYMPOSIUM ON AMYLOIDOSIS, pp. 58-59.

(2019). One year follow up analysis of the phase 1a/b study of chimeric fibril-reactive monoclonal antibody 11-1F4 in patients with AL amyloidosis. Amyloid: Vol. 26, Proceedings of the XVI International Symposium on Amyloidosis Kumamoto, Japan 26-29 March 2018, pp. 115-116.

With the growing knowledge of multiple myeloma (MM) pathobiology and the introduction of novel therapies, risk stratification continues to evolve. Myeloid-derived suppressor cells and tumor-associated macrophages, derived from peripheral blood monocytes, support malignant plasma cell proliferation in the bone marrow. Because peripheral blood absolute monocyte count (AMC) is thought to reflect the bone marrow microenvironment, we sought to evaluate the prognostic significance of AMC in MM. We retrospectively analyzed 10 822 patients newly diagnosed with MM between 2000 and 2019 at Veteran’s Administration hospitals. We obtained AMC closest to diagnosis and every 3 months thereafter up to 2.5 years. Patients were stratified into 4 groups: low, normal, elevated, and severely elevated AMC (<0.2, 0.2-<0.8, 0.8-<1.25, and ≥1.25 × 103/mm3, respectively). Abnormal AMC at diagnosis was observed in 25.3% of the patients and was associated with an inferior overall survival (OS). In patients with low, severely elevated, elevated, and normal AMC, respectively, median OS at diagnosis was 2.3, 2.7, 3.1, and 3.6 years (P < .001) and at 2.5 years was 2.0, 2.6, 3.4, and 3.9 years (P < .001). Patients with normal AMC at diagnosis who developed an abnormal AMC >1 year after diagnosis also had an inferior OS relative to patients who maintained a normal AMC. Abnormal AMC was also associated with inferior OS independent of validated prognostic markers, including the international staging system and lactate dehydrogenase. Our findings provide novel clues for future prospective studies on the functional role of monocytes in MM, which could be a readily available metric for risk stratification.

Bone marrow microenvironment plays an important role in promoting growth and survival of multiple myeloma (MM) cells. The tumor-promoting immune microenvironment is augmented while antitumor immune responses are inhibited. Although clinical and genomic markers of high-risk MM have been described, the immune status is just being recognized as a potential mediator of disease behavior. This is even more important with the development of a number of immune-based therapies. Based on these considerations, we evaluated peripheral blood absolute lymphocyte count (ALC) as an easily accessible marker representing immune microenvironment at diagnosis and after treatment of MM. We retrospectively evaluated 11 427 patients diagnosed with MM between 2000 and 2019 at Veterans Administration hospitals using ALC obtained closest to diagnosis and up to 2.5 years thereafter. Patients were stratified into 3 ALC categories: severely low, low, and normal (1.5 × 103/μL, respectively). Lymphopenia (including severely low and low ALC) was present in 53% of patients at MM diagnosis and was associated with inferior overall survival (OS). The median OS for patients with severely low, low, and normal ALC at diagnosis was 2.7, 3.3, and 4.2 years (P < .001), respectively. Moreover, persistent or new development of lymphopenia during treatment and follow-up was also associated with inferior OS. Our findings support the use of ALC as a biomarker for risk stratification in MM.