Retrospective comparison of a weight-based dose every 2 weeks with a fixed dose every month: a real-life analysis of nivolumab in the treatment of advanced melanoma.

Nivolumab was first authorized at a weight-based dose (WBD) of 3 mg/kg every two weeks (Q2W). Since 2017, a fixed dose (FD) regimen [first 240 mg Q2W and then 480 mg per month (Q4W)] was allowed. The objective of the study was to compare a WBD regimen and an FD regimen with regard to effectiveness and safety. We conducted a single-center, retrospective, real-life study of consecutive adult patients who had received a WBD of nivolumab or an FD of 480 mg Q4W. The primary endpoint was the occurrence of grade ≥3 immune-related adverse events (irAEs). The secondary endpoints were overall survival and cost of the treatment. In all, 342 patients were included: 71 in the WBD cohort and 271 in the FD cohort. Of these patients, 201 patients (59.6%) experienced an irAE, and 24 of these events were graded as ≥3. At 12 months, there was no significant difference in irAE occurrence between the two cohorts [hazard ratio (95% confidence interval): 0.54 (0.21-1.36), P  = 0.19]. The 12-month overall survival rate was significantly lower in the WBD cohort ( P  < 0.001). Switching from a fortnightly weight dose to a fixed monthly dose halves the cost of hospitalization. Our results did not show a significant difference between WBD and FD cohort in the occurrence of severe irAEs. However overall survival appeared to be significantly higher in FD group. Some clinical trials are investigating a hybrid dosing regimen in which a WBD is capped by an FD. The present results need to be confirmed in prospective studies.

A Spontaneous Model of Experimental Autoimmune Encephalomyelitis Provides Evidence of MOG-Specific B Cell Recruitment and Clonal Expansion.

The key role of B cells in the pathophysiology of multiple sclerosis (MS) is supported by the presence of oligoclonal bands in the cerebrospinal fluid, by the association of meningeal ectopic B cell follicles with demyelination, axonal loss and reduction of astrocytes, as well as by the high efficacy of B lymphocyte depletion in controlling inflammatory parameters of MS. Here, we use a spontaneous model of experimental autoimmune encephalomyelitis (EAE) to study the clonality of the B cell response targeting myelin oligodendrocyte glycoprotein (MOG). In particular, 94% of SJL/j mice expressing an I-As: MOG92-106 specific transgenic T cell receptor (TCR1640) spontaneously develop a chronic paralytic EAE between the age of 60-500 days. The immune response is triggered by the microbiota in the gut-associated lymphoid tissue, while there is evidence that the maturation of the autoimmune demyelinating response might occur in the cervical lymph nodes owing to local brain drainage. Using MOG-protein-tetramers we tracked the autoantigen-specific B cells and localized their enrichment to the cervical lymph nodes and among the brain immune infiltrate. MOG-specific IgG1 antibodies were detected in the serum of diseased TCR1640 mice and proved pathogenic upon adoptive transfer into disease-prone recipients. The ontogeny of the MOG-specific humoral response preceded disease onset coherent with their contribution to EAE initiation. This humoral response was, however, not sufficient for disease induction as MOG-antibodies could be detected at the age of 69 days in a model with an average age of onset of 197 days. To assess the MOG-specific B cell repertoire we FACS-sorted MOG-tetramer binding cells and clonally expand them in vitro to sequence the paratopes of the IgG heavy chain and kappa light chains. Despite the fragility of clonally expanding MOG-tetramer binding effector B cells, our results indicate the selection of a common CDR-3 clonotype among the Igk light chains derived from both disease-free and diseased TCR1640 mice. Our study demonstrates the pre-clinical mobilization of the MOG-specific B cell response within the brain-draining cervical lymph nodes, and reiterates that MOG antibodies are a poor biomarker of disease onset and progression.