South Korean biotech stocks’ issuers including Celltrion, Samsung Bioepis, LigaChem Biosciences, and IntoCell are accelerating the development of nectin-4 targeted antibody-drug conjugates, aiming to surpass the current market leader Padcev in safety and tolerability. In April, the U.S. FDA granted Celltrion’s CT-P71 fast track status.
Celltrion CT-P71: FDA fast track status
According to Celltrion’s announcement, CT-P71 is a nectin-4 ADC candidate jointly developed by Celltrion and the Korean biotech company Pinotbio. Global Phase I clinical trials were initiated in South Korea, the U.S., and other regions in July of last year. In April 2026, the FDA granted CT-P71 fast track status for patients with previously treated locally advanced or metastatic urothelial cancer.
CT-P71 uses a differentiated payload designed to cause damage during the DNA replication process in cancer cells. Preclinical studies show that it demonstrates consistent anti-cancer effects even in cancers that have developed resistance to Padcev. Celltrion’s clinical development plan is: in 2026, determine the appropriate dose in a Phase 1a trial; in 2027, conduct a Phase 1b trial to select effective solid tumor indications; then move into Phase II clinical trials with urothelial cancer as the primary indication.
Samsung Bioepis SBE303: Phase I launched this month in the U.S. and Korea
According to a statement from Samsung Bioepis, Samsung Bioepis, along with partner IntoCell, signed the final commercialization agreement the day before (July 23). SBE303 has already started Phase I clinical trials this month in the U.S. and South Korea, with plans to advance globally through July 2031.
SBE303 uses IntoCell’s OPAS linker platform technology and a payload from China’s cutting-edge biopharmaceutical industry. Samsung Bioepis and IntoCell signed a research agreement in December 2023 to jointly discover up to five ADC candidate drugs, and SBE303 was the first identified from that effort. Last month, preclinical results presented at AACR (American Association for Cancer Research) showed that SBE303’s tolerability was 13 times better than the originator therapy Padcev.
LigaChem Biosciences: Two candidate drugs and the Padcev market backdrop
According to the original report, LigaChem Biosciences is working with antibody development company Nectin Therapeutics to develop two candidate drugs by combining LigaChem’s ADC platform “ConjuALL” with Nectin Therapeutics’ antibody technology. The two candidates first appeared at the European Society for Medical Oncology (ESMO) annual meeting in October 2025, where preclinical studies showed efficacy and safety even at high doses, sparking market interest in whether they can improve on Padcev’s known issues of skin toxicity and neurotoxicity.
Padcev (enfortumab vedotin) was first approved by the FDA in December 2019 for metastatic urothelial cancer and was approved by South Korea’s Ministry of Food and Drug Safety in March 2026. It is the first ADC drug approved in South Korea for urothelial cancer.
FAQ
What are the timing and indication for the FDA fast track granted to Celltrion CT-P71?
According to the original report, in April 2026 the U.S. FDA granted Celltrion’s CT-P71 fast track status for patients with previously treated locally advanced or metastatic urothelial cancer; the global Phase I clinical trial began in July of last year.
How much better are the preclinical results for Samsung Bioepis SBE303 than Padcev?
According to preclinical results presented by Samsung Bioepis at AACR, SBE303’s tolerability was 13 times higher than the originator therapy Padcev; Phase I clinical trials have been launched in the U.S. and South Korea this month (July).
What is Padcev’s current approval status in South Korea?
According to the original text, in March 2026 South Korea’s Ministry of Food and Drug Safety approved Padcev (enfortumab vedotin) for treating locally advanced or metastatic urothelial cancer. It is the first ADC drug approved in South Korea for urothelial cancer.
