Merck Signs $2.8B VelosBio buyout to acquire anti-ROR1 ADC

Kenilworth, N.J.-based Merck has agreed to buy VelosBio for $2.75 billion. The takeover will give Merck control of VelosBio’s antibody-drug conjugate (ADC) that in a small clinical trial of diffuse large B-cell lymphoma (DLBCL) patients, caused objective responses in 80% of previously treated DLBCL patients. The ADC, called VLS-101, targets ROR1, a tyrosine-protein kinase transmembrane receptor thought to be overexpressed in several types of cancers. Merck has opted to buy VelosBio in the run up to the presentation of data that will start the process of validating the target. At the American Society of Hematology’s annual meeting next month, VelosBio will share data from a Phase I trial that administered VLS-101 to previously treated hematological cancer patients. Seven of the 15 mantle cell lymphoma patients had objective responses after treatment with the ADC. Four of the five patients in the DLBCL cohort had objective responses. Objective response rates of 47% and 80% in the two patient populations were sufficiently robust to convince Merck to purchase VelosBio. Some patients experienced complete responses. FDA approved the first ADC in 2000, but it is only in recent years that the modality has consistently delivered noteworthy data.