Nintedanib Treatment in Unicentric Castleman Disease

Unicentric Castleman Disease (UCD) is a rare non-malignant localised disease involving one or more lymph nodes, associating germinal centre atrophy, mantle zone thickening and intense vascular proliferation penetrating the germinal centres. Patients usually seek medical attention because of a localised, sometimes compressive, lymph node or the development of life-threatening autoimmune complications (paraneoplastic pemphigus or PNP or myasthenia gravis or MG). The best treatment option is complete surgical excision, but it has been recently demonstrated that up to half of the patients cannot undergo surgery. In these patients, an efficient medical approach needs be defined, as no current medical treatment has demonstrated to lower morbidity and mortality. The cause of UCD is currently unknown and current data favour a scenario of stromal impairment leading to the loss of lymph node architecture rather than one of a primary hematopoietic disease. UCD lesions are often associated with synchronous follicular dendritic cell (FDC) proliferation and can sometimes evolve towards a true FDC sarcoma (FDCS), indicating a possible role for FDC, a germinal centre stromal cell component, in UCD pathogenesis. A recurrent somatic activating mutation in PDGFRB (p.N666S) has been recently described in the CD45 negative (non-hematopoietic) compartment of up to 17% UCD specimens. Moreover, activation of the VEGFR pathway is thought to play a role in the development of the disease, especially in the increased vascularity characteristic of the UCD lesion.

Nintedanib is a commercially available tyrosine-kinase inhibitor targeting PDGF, VEGF and FGF receptors. The drug has obtained European Market Authorization in 2015 for the treatment of Non-Small Cell Lung Cancer and Idiopathic Pulmonary Fibrosis with a satisfactory safety profile. The hypothesis is that nintedanib could benefit patients with unresectable or partially resectable UCD.