Xencor, Inc. announced it will regain exclusive worldwide rights to plamotamab, a CD20 x CD3 bispecific T-cell engager, which Xencor advanced through Phase 1 clinical development in hematologic cancers. In 2021, Xencor entered a collaboration and license agreement with Janssen Biotech, Inc. to develop and commercialize plamotamab and novel B-cell targeting bispecific antibodies designed to conditionally activate T cells through the CD28 co-stimulatory receptor. Xencor completed enrollment in a Phase 1 study of plamotamab in late 2023.

Xencor has been notified that Janssen will terminate its rights to plamotamab under the collaboration and license agreement. Janssen has retained its rights to develop and commercialize B-cell targeting CD28 bispecific antibodies, including JNJ-9401 (PSMA x CD28) and JNJ-1493 (CD20 x CD28). Under Xencor?s two collaboration agreements with Janssen, Xencor and Janssen conducted joint research activities to discover XmAb® bispecific antibodies against CD28 and select targets, with Janssen maintaining exclusive worldwide rights to develop and commercialize licensed products identified from the research activities.

Janssen has advanced JNJ-9401and JNJ-1493 into Phase 1 clinical studies. Xencor is eligible to receive additional development, regulatory and sales-based milestone payments, and tiered royalties on approved products in the high-single to low-double digit percentage range of net sales. Upon clinical proof-of-concept for each program, Xencor has the right to opt-in to fund 20% of development costs (JNJ-9401) or 15% of development costs (JNJ-1493 or other B-cell targeting bispecifics) and to perform up to 30% of detailing efforts in the United States.

If Xencor exercises these rights, the Company would then be eligible to receive tiered royalties in the low-double digit to mid-teen percentage range.