Xencor’s New Study on XmAb657: A Potential Game-Changer for Muscle Diseases

Xencor Inc. (XNCR) announced an update on their ongoing clinical study.

Study Overview: Xencor Inc. has launched a Phase 1 study titled A Phase 1, First-in-Human, Open-Label, Dose-Escalation Study to Evaluate the Safety and Tolerability, Pharmacokinetics, and Pharmacodynamics of XmAb657 in Healthy Participants and in Participants With Idiopathic Inflammatory Myopathy. The study aims to assess the safety and tolerability of XmAb657, a promising treatment for idiopathic inflammatory myopathy (IIM), a group of rare muscle diseases. This research is significant as it could lead to new therapeutic options for patients with limited current treatments.

Intervention/Treatment: The study is testing XmAb657, a biological intervention administered subcutaneously. Its primary purpose is to evaluate the safety and tolerability of this treatment in both healthy individuals and those with IIM.

Study Design: This is an open-label, single-group study with no masking involved, focusing on treatment as its primary purpose. Participants will receive escalating doses of XmAb657 to determine its safety profile.

Study Timeline: The study is scheduled to start on December 3, 2025, with its primary completion and estimated completion dates yet to be announced. The latest update was submitted on December 15, 2025, indicating that the study is not yet recruiting participants.

Market Implications: The initiation of this study could positively impact Xencor’s stock performance, as successful results may lead to new treatment options for IIM, potentially increasing investor interest. The study’s progress will be closely watched by investors, given the competitive landscape of biopharmaceuticals targeting rare diseases.

The study is ongoing, with further details available on the ClinicalTrials portal.

To learn more about XNCR’s potential, visit the Xencor Inc. drug pipeline page.