Korean biotech OliX Pharmaceuticals has locked in a $3 million milestone payment from China’s Jiangsu Hansoh Pharmaceutical after an optioned RNAi drug candidate moved into preclinical development -- marking the first tangible progress under a deal that could ultimately be worth over $100 million.

The milestone, disclosed Thursday, was triggered as the GalNAc-conjugated asymmetric siRNA (asiRNA) candidate, designed to deliver gene-silencing molecules to the liver, entered GLP toxicology prep, an early-stage safety step required before animal testing begins.

OliX said it issued the invoice on Wednesday and expects to receive payment within 60 days.

It’s a critical step forward in a broader collaboration that dates back to 2021, when OliX granted Hansoh exclusive rights to develop and commercialize GalNAc-asiRNA therapeutics for cardiovascular and metabolic diseases in Greater China. That deal included two option rights for additional candidates, one of which Hansoh exercised in February 2023 with a $2.25 million upfront payment.

The full value of the exercised option, including development milestones and royalties, could reach $112.25 million, according to terms disclosed at the time. OliX is also eligible to receive 10 percent of net sales if the drug reaches commercialization.

Altogether, the original 2021 license covers four potential candidates, with two under the main agreement and two through option rights, for a total deal value of up to $451 million. OliX retains rights to all territories outside Greater China and said it is actively exploring additional out-licensing opportunities overseas.

“This is the first real development milestone on a candidate beyond our original contract with Hansoh,” CEO Lee Dong-ki said in a statement. “It is a meaningful step in the partnership and underscores the value of our GalNAc-asiRNA platform as it moves through global pipelines.”