Xencor announced that their investigational treatment for lgG4-Related Disease (lgG4-RD) – a fibro-inflammatory autoimmune disorder – has been granted orphan drug status by the Food and Drug Administration (FDA).

XmAb5871 is a first-in-class monoclonal antibody that targets CD19 and the receptor that inhibits B-cell function, FcyRIIb. There is currently no approved treatment for lgG4-RD, which is a newly recognized disorder and is estimated to affect 40,000 individuals in the U.S.

“New treatment options are clearly needed, and we are diligently moving XmAb5871 forward in clinical development to fill this void,” said Bassil Dahiyat, PhD, president and CEO of Xencor. “Preliminary data from our Phase 2 study of XmAb5871 showed promising activity in patients with lgG4-RD, and we are on track to complete the study and report topline results by the end of the year.” 

Related Articles

Results from the Phase 2 study demonstrated that 9 out of 11 (82%) patients who received XmAb5871 achieved initial response within 2 weeks of their first dose. Disease remission (IgG4-RD responder index of 0) was attained by 5 study participants.

One patient discontinued the study due to hypersensitivity reaction with rash and arthritis which was deemed moderate. Three patients (25%) reported the treatment-related adverse event of abdominal pain and 2 patients reported headache, both these cases were deemed mild.

“We are planning to engage the FDA later this year to discuss future clinical trials and potential registration requirements in IgG4-RD,” said Mr. Dahiyat.

For more information visit Xencor.com.