Xencor Regains All Rights From Amgen To Rare AutoImmune Disease Drug, Dumps Arthritis Hopes

October 29, 2014

By Jessica Wilson, BioSpace.com Breaking News Staff

Antibody biotech Xencor today announced it has regained rights to arthritis drug XmAb5871 from Amgen , as it begins Phase 1b/2a clinical trials on patients with moderate-to-severe rheumatoid arthritis (RA), the results of which are expected by the end of 2014.

“We determined that even with positive data following completion of the ongoing Phase 1b/2a trial in rheumatoid arthritis, refocusing our development plan on other autoimmune diseases would align better with Xencor's strategy to develop therapies for diseases with the highest unmet need,” Bassil Dahiyat, president and CEO of Xencor, said in a statement. “We do not plan on starting a Phase 2b rheumatoid arthritis trial in 2015,” which seems to indicate the company has abandoned patients with rheumatoid arthritis as a target market.

Dahiyat emphasized that, “We approached Amgen to end the original collaboration to allow Xencor the freedom to pursue alternative clinical and commercial paths. Amgen agreed, provided we grant them a right of first negotiation for a license to XmAb5871.”

In the original agreement, which the two companies entered into in December 2010, Amgen was granted an option to an exclusive worldwide license of XmAb5871 after the completion of a Phase II study in patients with rheumatoid arthritis. Thus far, Monrovia, Calif.-based Xencor has been leading all clinical development of XmAb5871.

XmAb5871 is an antibody containing Xencor's proprietary immune inhibitor XmAb Fc domain that targets FcRIIb to inhibit B-cell function. B-cell inhibition could be a promising treatment for a rare condition called “IgG4-related disease,” a fibro-inflammatory autoimmune disorder that affects approximately 10,000-20,000 patients in the U.S. Currently no therapies exist for this disease, which is controlled, but not treated, by corticosteroids.

According to Dahiyat, Xencor will begin clinical testing in IgG4-related disease in 2015.

Dahiyat added, “This [new] agreement enables Xencor to regain rights to our Phase 2 asset and pursue what we feel is a stronger clinical development plan while maintaining our previously stated financial expectation that we will have sufficient cash to fund research and development programs and operations through 2016. We expect to have 2014 year-end cash and cash equivalents of approximately $54 million.”

Xencor will host a conference call today at 5 p.m. EDT to discuss this announcement.