NEJM articles describe research on obexelimab, an investigational treatment intended to target B cells in IgG4-related disease while aiming to avoid the broader effects associated with B-cell–depleting therapies. The studies focus on the biologic rationale and clinical evaluation of a “nondepleting” approach, in which obexelimab interferes with aspects of B-cell activity rather than eliminating B cells entirely. Across the NEJM coverage, the drug is presented as a potential option for patients with IgG4-related disease, a condition characterized by inflammatory lesions that can affect multiple organs. The reports emphasize that obexelimab’s mechanism is designed to modulate the immune response more selectively. The NEJM publications also frame the work as part of an ongoing effort to improve outcomes and tolerability in IgG4-related disease, where current therapies can have limitations for long-term disease control and safety. (Details such as study design specifics, patient numbers, and efficacy outcomes were not provided in the supplied source text.)