Xencor, Inc. and MorphoSys AG announced that they have initiated phase 1 testing for XmAb5574 (MOR208), and the first patient has been dosed. XmAb5574 (MOR208) is a potent monoclonal anti-CD19 antibody to which MorphoSys recently gained worldwide access via an exclusive license and collaboration agreement with Xencor. The trial is designed to assess the drug’s safety, tolerability, pharmacokinetic profile and preliminary anti-tumour activity in chronic lymphocytic leukaemia (CLL) patients. The open-label, multi-dose, single-arm, dose-escalation study is estimated to enrol 30 patients suffering from relapsed or refractory CLL.

“This is the fourth high ADCC antibody based on our XmAb technology that has reached the clinic, demonstrating the tremendous progress our optimization technologies have made in producing next-generation biological drugs,” said Bassil Dahiyat, Ph.D., CEO of Xencor. “We’ll be collaborating with our new partner MorphoSys through phase 1, and are sure that their antibody expertise and product development capabilities will help accelerate the compound’s clinical progress.”

“With MOR208, our second proprietary compound enters clinical trials in addition to currently ten programs being developed in the clinic by our partners,” commented Dr. Arndt Schottelius, chief development officer of MorphoSys AG. “CD19 represents a particularly attractive immunotherapy target for cancers of lymphoid origin, due to its high expression levels on non-Hodgkin’s lymphomas and B-cell leukaemias such as chronic lymphocytic leukaemia.”

In preclinical studies, XmAb5574 (MOR208) was well tolerated at various dose levels, elicited immediate and sustained B-cell depletion, and showed strong anti-tumour potency, anti-proliferative and apoptotic activity. B-cell malignancies, such as non-Hodgkin’s lymphoma, chronic lymphocytic leukaemia (CLL) and acute lymphoblastic leukaemia afflict more than one hundred and fifty thousand patients in the seven major markets each year. CD19 is expressed more broadly and earlier in B-cell development than CD20, the target of the marketed cancer drug Rituxan, therefore potentially allowing for an even broader use of XmAb5574 (MOR208) as compared to Rituxan.

Xencor, Inc. engineers superior biotherapeutics using its proprietary Protein Design Automation technology platform, and is a leader in the field of antibody engineering to significantly improve antibody half-life, immune-regulatory function and potency.