CStone Pharmaceuticals has announced a licensing agreement with LegoChem Biosciences, Inc., (LCB) for the development and commercialization of LCB71, a potential first-in-class/best-in-class antibody drug conjugate (ADC).

Under the agreement, Chinese firm CStone obtains the exclusive global right to lead development and commercialization of LCB71 outside the Republic of Korea. LCB will receive an upfront payment of $10 million, and up to $353.5 million in cumulative milestone payments, plus tiered royalties.

LCB71 is a pre-clinical ADC entering into Investigational New Drug (IND) enabling studies. It targets ROR1 (receptor tyrosine kinase-like orphan receptor 1), a high-potential ADC target for multiple solid and hematological malignancies. ROR1 protein expression is prevalent in a variety of cancers including various forms of leukemia, non-Hodgkin lymphoma, and breast, lung, and ovarian cancers.

LCB71 has a proprietary tumor-activated pyrrolobenzodiazepine (PBD) prodrug toxin that addresses the typical toxicity problem associated with traditional PBD payloads. It has demonstrated complete tumor inhibition across several preclinical cancer models, which may translate into a wide therapeutic index for a range of solid and hematologic malignancies. Additionally, it utilizes site-specific conjugation for a precise drug antibody ratio. This supports serum half-life and improves its pharmacokinetic profile, and also enables homogeneous production and large-scale manufacturing.