Merus announced that Incyte has elected to opt-out of its ex-U.S. development of MCLA-145, restoring full global rights to Merus. MCLA-145 is currently enrolling a global, phase 1, open-label, single-agent clinical trial evaluating MCLA-145 in patients with solid tumors. The trial consists of a dose escalation phase, followed by a planned dose expansion phase.

Merus is also planning to evaluate the combination of MCLA-145 with a PD-1 blocking antibody. Under the terms of a 2017 Collaboration and License Agreement (Agreement) between Merus and Incyte, Incyte received ex-U.S. rights to MCLA-145. Incyte's opt-out of ex-U.S. rights to MCLA-145 provides Merus the exclusive right to develop and commercialize potential MCLA-145 products globally.

As part of the Agreement, Incyte will continue to support the program for a limited time while ex-U.S. activities are transitioned to Merus, and Incyte will also retain a right to a residual royalty of up to 4% on sales of future commercialization of MCLA-145, if approved. Additionally, per the Agreement, the parties will continue to collaborate on the development and commercialization of up to ten bispecific or monospecific antibody programs. Merus also has the option to co-fund development of product candidates arising from two programs. For any program for which Merus exercises its co-development option, Merus would be responsible for 35% of global development costs in exchange for a 50% share of U.S. profits and losses and tiered royalties ranging from 6 to 10% on ex-U.S. sales by Incyte for these programs. Merus also has the right to elect to provide up to 50% of detailing activities for product candidates arising from one of these programs in the U.S.