Single-agent daratumumab for refractory POEMS syndrome

Hematologic malignancies and hematopoietic stem cell transplantation

Paraneoplastic neurologic syndromes are rarely associated with hematologic malignancies. In their rarity, lymphomas are the diseases with more frequent paraneoplastic neurologic syndrome. High-risk antibodies are absent in most lymphoma-associated paraneoplastic neurologic syndromes, with the exception of antibodies to Tr/DNER in paraneoplastic cerebellar degeneration, mGluR5 in limbic encephalitis, and mGluR1 in some cerebellar ataxias. Peripheral nervous system paraneoplastic neurologic syndromes are rare and heterogeneous, with a prevalence of demyelinating polyradiculoneuropathy in non-Hodgkin lymphoma. Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) is a rare, paraneoplastic syndrome due to an underlying plasma cell disorder. The diagnosis is based on defined criteria, and vascular endothelial growth factor (VEGF), not an antibody, is considered a reliable diagnostic marker that also mirrors therapy response. As with the paraneoplastic neurologic syndromes in solid tumors, therapies rely on cancer treatment associated with immunomodulatory treatment with better response in PNS with antibodies to surface antigens. The best outcome is generally present in Ophelia syndrome/limbic encephalitis with anti-mGluR5 antibodies, with frequent complete recovery. Besides patients with isolated osteosclerotic lesions (where radiotherapy is indicated), hematopoietic stem-cell transplantation is the therapy of choice in patients with POEMS syndrome. In the paraneoplastic neurologic syndromes secondary to immune checkpoint inhibitors, discontinuation of the drug together with immunomodulatory treatment is recommended.

POEMS syndrome in the 21st century: A bibliometric analysis

Background

POEMS syndrome is a rare and complex plasma cell disorder characterized by polyneuropathy, organomegaly, endocrinopathy, high M protein levels, and skin changes. Understanding of POEMS syndrome has advanced rapidly since the 21st century. This study aims to summarize and evaluate the research status of POEMS syndrome in the past 23 years through a bibliometric and visualization analysis, and identify research focuses and emerging hotspots for the future.

Methods

POEMS syndrome-related articles published between January 1, 2000, and March 8, 2023, were systematically retrieved from the Web of Science Core Collection. Data processing and visualization analysis were carried out using a combination of R software, HistCite, VOSviewer, and CiteSpace.

Results

Since entering the 21st century, 3677 authors from 1125 institutions in 68 countries/regions have published 830 original and review articles on POEMS syndrome in 408 journals so far, among which the USA, Japan, and China published the most articles, and Mayo Clinic, Udice French Research Universities, and Peking Union Medical College listed the top three most prolific institutions. However, collaborative research across countries and groups in the study of POEMS syndrome remain significantly limited. Angela Dispenzieri ranked first in POEMS syndrome research from every aspect of authors, producing the most papers and contributing the most-cited article, followed by Satoshi Kuwabara and Sonoko Misawa. Internal medicine was the most productive journal on POEMS syndrome. "endothelial growth factor" was the keyword with the highest occurrence except for "POEMS syndrome", and "bevacizumab", "lenalidomide", "dexamethasone", and "management" were recognized as emerging topics.

Conclusion

This study utilized bibliometric and visualization analysis to systematically summarize the research of POEMS syndrome in the first two decades of the 21st century, offering a data-based and objective perspective on the field of POEMS syndrome and guiding researchers in the identification of novel research directions.

B-cell targeting with anti-CD38 daratumumab: implications for differentiation and memory responses

B cell-targeted therapies, such as CD20-targeting mAbs, deplete B cells but do not target the autoantibody-producing plasma cells (PCs). PC-targeting therapies such as daratumumab (anti-CD38) form an attractive approach to treat PC-mediated diseases. CD38 possesses enzymatic and receptor capabilities, which may impact a range of cellular processes including proliferation and differentiation. However, very little is known whether and how CD38 targeting affects B-cell differentiation, in particular for humans beyond cancer settings. Using in-depth in vitro B-cell differentiation assays and signaling pathway analysis, we show that CD38 targeting with daratumumab demonstrated a significant decrease in proliferation, differentiation, and IgG production upon T cell-dependent B-cell stimulation. We found no effect on T-cell activation or proliferation. Furthermore, we demonstrate that daratumumab attenuated the activation of NF-κB in B cells and the transcription of NF-κB-targeted genes. When culturing sorted B-cell subsets with daratumumab, the switched memory B-cell subset was primarily affected. Overall, these in vitro data elucidate novel non-depleting mechanisms by which daratumumab can disturb humoral immune responses. Affecting memory B cells, daratumumab may be used as a therapeutic approach in B cell-mediated diseases other than the currently targeted malignancies.