Samsung Bioepis Secures Nexatecan3 Rights for Three Cancer Drug Candidates

Samsung Bioepis has secured rights to use Intocell’s Nexatecan3 payload in up to three antibody-drug conjugate candidates, clarifying the scope of a license that is central to the Korean drugmaker’s expansion into novel cancer medicines.

The company obtained rights to use a patent held by China-based Frontline covering the chemical structure of Nexatecan3. Samsung Bioepis signed an exclusive license agreement with Frontline in October 2025 after a patent issue emerged while it was preparing its first jointly developed antibody-drug conjugate for clinical testing. The specific scope of the license has now been confirmed.

Antibody-drug conjugates, commonly known as ADCs, combine an antibody designed to target cancer cells with a toxic payload intended to destroy them. Samsung Bioepis has worked with Korean biotechnology company Intocell since 2023 on joint research involving as many as five ADC targets. Under that collaboration, Samsung Bioepis discovers the antibodies while Intocell provides payload and linker technologies.

The license permits Nexatecan3 to be used in fewer candidates than the five contemplated under the companies’ research arrangement. SBE303, the first drug to use the payload, is already in global Phase 1 trials. That leaves room for only two additional jointly developed candidates to use Nexatecan3 under the confirmed rights.

The limitation puts greater importance on Intocell’s newer payload technologies if the partners are to complete all five candidates envisaged in their collaboration. Intocell has announced two next-generation payloads, Nexatecan32 and Isonexatecan3, as potential successors to Nexatecan3. An industry official said Samsung Bioepis appeared likely to use all the rights obtained from Frontline, while additional candidates would need to incorporate Intocell’s newer payloads.

The development also highlights Samsung Bioepis’ broader effort to build a proprietary drug pipeline beyond the biosimilars for which it is best known. The company has widened its ADC partnerships in China, including a joint development agreement with Frontline for two bispecific-antibody and dual-payload candidates. It also established a research partnership this year with Atlatl Innovation Center, a Chinese biotechnology research and development platform.

The confirmed license gives Samsung Bioepis a clearer path for advancing SBE303 and two more Nexatecan3-based assets, but it also sets a firm boundary around the technology available for the wider Intocell collaboration. Progress with the newer payloads will therefore be an important factor in determining whether the partners can fill out the full five-candidate research program.