Aptsci
Seoul, KR Β· Public Β· 2 known investors
AptsciAptamer Science develops aptamer-based drug delivery and diagnostic platforms for precision medicine applications. The company specializes in cancer therapeutics using its proprietary ApDC (Aptamer-Drug Conjugate) technology, as well as early-stage lung cancer diagnostic kits and emerging programs in immunotherapy and metabolic disease.
Also known as Aptamer Sciences Β· Aptamer Sciences Inc. Β· AptSci Β· μνλ¨Έμ¬μ΄μΈμ€
Founders & leadership
Investors Β· 2
Company profile
researched Aug 2026Aptamer Sciences Inc. (AptSci) is a South Korean biotechnology company built around aptamer technology β single-stranded oligonucleotides, roughly 40 nucleotides long, that bind protein targets with high specificity and affinity. The company operates an integrated aptamer discovery platform based on its own SELEX and optimization methods using modified nucleic acids, and applies it through ApDC (Aptamer-Drug Conjugate), a targeted drug-delivery platform in which a cytotoxic payload is conjugated to a target-binding aptamer. The company positions aptamers as roughly one-tenth the molecular size of antibodies, arguing this yields greater tumor penetration and lower immunogenicity than antibody-drug conjugates (ADCs). It has also completed development of a proprietary dendrimer-type linker technology that allows multiple payloads per aptamer and raises the drug-to-aptamer ratio, with domestic Korean and PCT patent applications filed.
The lead program, AST-201, is an ApDC pairing a GPC3-binding aptamer with the chemotherapeutic gemcitabine, developed for hepatocellular carcinoma and other GPC3-positive solid tumors including non-small cell lung cancer. An IND for a Phase 1 trial was filed with Korea's Ministry of Food and Drug Safety in March 2024, and the trial runs across CHA Bundang Medical Center, Samsung Medical Center, Severance Hospital and the National Cancer Center, with Dr. Hong Jae Chon as coordinating investigator. Additional pipeline assets include AST-202 targeting CD25 in hemato-oncology, AST-203, a Trop2-targeting ApDC presented in preclinical form at AACR 2025, a Trop2-ApDC program selected for Korea's National New Drug Development Program, plus ApRC (Aptamer Radioligand Conjugate) and ApIS (Aptamer Immune Stimulator Conjugate) modalities and an aptamer-siRNA conjugate effort.
Alongside therapeutics, the company has offered aptamer research tools and services, including catalogued validated DNA aptamers, custom aptamer generation against customer-supplied targets, AptoPrep protein isolation kits based on an aptamer "aptoprecipitation" pull-down method for receptor tyrosine kinases, and the AptoCyto cell separation kit, as well as aptamer-based exosome and HCV isolation kits under development.
Business model
The company develops proprietary aptamer-based drug candidates and platform technologies, seeking value through clinical advancement, out-licensing/technology transfer and co-development agreements with global pharmaceutical companies and research institutions. It has also commercialized aptamer research products and custom aptamer generation services for research, diagnostic and therapeutic applications.
Reported funding sources include revenue from aptamer services and products, together with government grants and investment from strategic investors; the therapeutics business is oriented toward technology-transfer and co-development deals.
Traction
AST-201 Phase 1 dosed its first patient in March 2025 and reached cohort 3 by June 2025, with tolerability and safety described as favorable; the trial runs at four Korean hospitals. In April 2026 the company signed a clinical trial collaboration and supply agreement with Merck (MSD) covering a Phase 2 combination study of AST-201 with pembrolizumab (Keytruda). A Trop2-ApDC program was selected for Korea's National New Drug Development Program in June 2026, providing two years of government support, and a US composition-of-matter patent for AST-201 was registered in August 2026, adding to prior rights in Korea, China and Japan. A joint development agreement with Curigin covers aptamer-conjugated bispecific siRNA therapeutics.
Latest developments
In August 2026 the company announced registration of a US patent covering AST-201's composition of matter, following its April 2026 clinical trial collaboration and supply agreement with Merck for combination studies with Keytruda and the June 2026 selection of its Trop2-ApDC program for Korea's National New Drug Development Program, which funds lead optimization and preclinical work over two years. The company states it is pursuing global technology transfer and co-development opportunities for both programs.
βΈFull profile β market position, technology, go-to-market, geography, history
Market position
The company describes itself as a KOSDAQ-listed player in the aptamer field with an integrated aptamer technology platform focused on oncology pipelines, and frames ApDC as complementary to antibody-drug conjugates by addressing ADC limitations in solid-tumor penetration, immunogenicity and toxicity.
Differentiation is claimed on aptamer size (approximately one-tenth that of an antibody) giving deeper tumor penetration; the ability to target GPC3, described as difficult to address with ADCs, with rapid cellular internalization; a dendrimer linker raising payload capacity; and preclinical AST-203 data reported at up to 8x higher tumor penetration than conventional ADCs with lower toxicity. Management also cites unusually fast Phase 1 cohort escalation for AST-201.
Technology
Core technology is a proprietary SELEX-based aptamer discovery and optimization platform incorporating modified nucleic acids for improved binding specificity and stability. On top of it sits ApDC (Aptamer-Drug Conjugate) for targeted delivery of small-molecule payloads, extended by a dendrimer-type linker enabling multiple payloads per aptamer and an adjustable drug-to-aptamer ratio via thiol-mediated click conjugation. Related modalities include ApRC (Aptamer Radioligand Conjugate), ApIS (Aptamer Immune Stimulator Conjugate) and aptamer-siRNA conjugates. Research-tool technologies include aptoprecipitation protein pull-down using aptamers conjugated to magnetic beads (AptoPrep) and aptamer-based cell separation (AptoCyto) with FITC/biotin bi-labeling for downstream flow cytometry.
Go-to-market
Clinical development is conducted in Korea across major hospital sites, while business development runs through partnering activity β private partnering meetings with global pharmaceutical companies and investors at BIO USA 2025, data presentations at AACR 2025, a clinical trial collaboration and supply agreement with Merck (MSD), and material transfer agreements and joint research with Korean biotech firms.
Oncology patient populations addressed through clinical development (hepatocellular carcinoma, GPC3-positive advanced solid tumors, Trop2-expressing solid tumors, hemato-oncology), with global pharmaceutical companies and research institutions as licensing and co-development counterparties; research-product customers include universities, hospitals and research organizations.
Geography
Operations are centered in South Korea, with corporate locations referenced as Seoul, Seongnam and Pohang; clinical trials are run at Korean hospitals, and business development activity extends to the United States, including partnering at BIO USA in Boston and discussions with a US National Cancer Institute-affiliated research organization. Patents for AST-201 are held in Korea, China, Japan and the United States.
History
AptSci was launched in 2011 in Pohang, South Korea, initially commercializing aptamer generation services and research products such as AptoPrep protein isolation kits and the AptoCyto cell separation kit, under leadership including Sung Ho Ryu, Dongil Han and Sung Key Jang, with an advisory board including Marty Stanton, Byung Hwan Ryoo, Yoon Keun Kim and Andy Ellington. The company subsequently listed on KOSDAQ (ticker 291650) and shifted emphasis to therapeutic development, completing a proprietary ApDC linker technology, filing an IND for AST-201 in March 2024, beginning Phase 1 dosing in March 2025 and expanding into combination clinical work with Merck and additional ApDC, ApRC and siRNA programs.
Compiled by commissioned research from 5 cited public sources β announcements, filings, and press listed under research sources below.
Key figures
latest reportedCompany-reported or press-reported figures, each dated to when it was claimed β not independently audited.
Timeline Β· 8
launches, deals, and filingsThe company announced that the composition-of-matter patent for AST-201, a GPC3-targeting ApDC, was registered with the US Patent and Trademark Office, adding to existing patent rights in Korea, China and Japan.
The company's Trop2-targeting ApDC candidate was selected as a research project under Korea's National New Drug Development Program, providing government support over two years for lead optimization and preclinical development.
Aptamer Sciences signed a Clinical Trial Collaboration and Supply Agreement with Merck (MSD) to evaluate AST-201 in combination with the anti-PD-1 therapy Keytruda (pembrolizumab) in a Phase 2 trial; Merck supplies Keytruda and provides scientific collaboration.
Aptamer Sciences and RNA gene therapy developer Curigin agreed to jointly develop aptamer-based precision-targeted siRNA therapeutics, combining Aptamer Sciences' targeted delivery technology with Curigin's bispecific siRNA platform.
The AST-201 Phase 1 trial entered its third dose cohort roughly three months after first patient dosing, with tolerability and safety reported as favorable.
Preclinical results for AST-203, a Trop2-targeting ApDC, were presented at AACR 2025, reporting up to 8x higher tumor penetration than conventional ADCs, lower toxicity and antitumor efficacy; a technical review meeting with a US National Cancer Institute-affiliated research organization followed.
Dosing of the first patient began in the domestic Phase 1 trial of AST-201 for hepatocellular carcinoma, conducted at the National Cancer Center, CHA Bundang Medical Center, Samsung Medical Center and Severance Hospital.
Aptamer Sciences filed an Investigational New Drug application with the Korean Ministry of Food and Drug Safety for a Phase 1 trial of AST-201, a GPC3-targeting ApDC with gemcitabine payload, in GPC3-positive advanced solid tumors.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
βΈResearch sources Β· 5
primary sources listed
- Aptsciaptsci.com Β· web
5 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does Aptsci do?
- Korean KOSDAQ-listed biotech developing aptamer-drug conjugate (ApDC) oncology therapeutics and aptamer research products.
- Who are Aptsci's investors?
- Aptsci's investors include Aju IB Invesment Corporation, Kiwoom Investment.
- Where is Aptsci headquartered?
- Aptsci is headquartered in Seoul, KR.