MorphoSys, Xencor Publish Phase 1/2a Trial's Final Results Of MOR208 In CLL/SLL

(RTTNews) - MorphoSys AG (MPSYY.PK) and Xencor Inc. (XNCR) reported the publication of final results of a Phase 1/2a trial evaluating MOR208, formerly XmAb5574, in patients with relapsed or refractory chronic lymphocytic leukemia/small lymphocytic leukemia or CLL/SLL.

MOR208, a potent anti-CD19 antibody with a proprietary modification to the Fc portion that is being developed to treat B-cell malignancies, was in-licensed by MorphoSys from Xencor in 2010.

The results show that the drug was well tolerated and achieved durable responses in a high risk and poor prognosis patient population with significant progression-free survival achieved. At recommended dose 12 patients or 75% had a partial response by physical exam criteria and 6 patients or 37.5% had a partial response using additional CT criteria. Blood disease cleared in most patients, with median reduction in absolute lymphocyte count from baseline of 90.8%; and Progression-free survival of up to 60 weeks for patients in extended treatment arm.

The Phase 1/2a study was designed to evaluate the drug's safety, tolerability, pharmacokinetic profile and preliminary anti-tumor activity. MOR208 was administered as an intravenous infusion on days 1, 4, 8, 15, and 22 of cycle 1, and on days 1, 8, 15, and 22 of cycle 2. Dose levels tested ranged from 0.3 to 12 mg/kg with an expansion to a total of 16 patients at the highest dose.