[Edaily Reporter Kim Jinsoo ] Aptabio Therapeutics Inc.(293780) “Apta-16,” a new drug candidate for blood cancer, has been selected for presentation at major international cancer conferences for the third consecutive time, drawing attention on the global stage of anticancer drug development.

In particular, unlike existing antibody-drug conjugates (ADCs), Apta-16 is based on next-generation drug delivery technology utilizing aptamers. As global competition in the ADC sector intensifies, interest in XDCs—a new type of drug complex—is growing, and interest in Apta-16 is expected to continue. Furthermore, analysts suggest that Apta-16 has a high potential for technology export, given its demonstrated ability to target resistance to existing anticancer drugs.

From AACR to ESMO… Three Consecutive Presentations

According to the pharmaceutical and biotech industry on the 21st, Aptabio Therapeutics Inc. will present the Phase 1 clinical trial design for Apta-16 as a poster at the European Society for Medical Oncology (ESMO) conference, taking place in Madrid, Spain, from the 23rd to the 27th.

Following the presentation of preclinical results for Apta-16 at the American Association for Cancer Research (AACR) conferences last year and this year, Aptabio Therapeutics Inc. will unveil its clinical development strategy at ESMO 2026.

Specifically, at AACR 2025, the company presented research findings showing that Apta-16 maintains anticancer activity even in blood cancer cells resistant to the existing anticancer drug cytarabine; this year, it identified the mechanism of action involved in resistance to another anticancer drug, venetoclax. At this year’s ESMO, the company will unveil the Phase 1 clinical trial design intended to apply these two studies to actual patients.

An Aptabio Therapeutics Inc. official stated, “The fact that we have made three consecutive presentations at major cancer conferences, even without clinical efficacy data yet, signifies that our aptamer-based drug delivery technology and treatment strategies for intractable blood cancers are attracting significant attention on the global stage.”

As ADC Competition Intensifies, XDC Emerges… Focus Shifts to Aptamers

Another reason Apta-16 is garnering

attention

is the shifting landscape of the global anticancer drug development market. While ADCs have recently established themselves as a core area for next-generation anticancer drugs in the global pharmaceutical industry, competition is becoming increasingly fierce as numerous candidate compounds are being developed around major targets such as HER2 and TROP2.

As the number of competing drugs targeting the same targets increases, securing new targets and differentiated drug delivery technologies has emerged as a critical challenge, leading to expanded research into “XDC” (X-Drug Conjugate), a new form of drug conjugate that goes beyond ADCs.

XDC refers to a variety of conjugates, such as those that use substances other than antibodies as target-recognition agents or those that bind drugs other than conventional cytotoxic anticancer agents. Research is underway on methods that utilize peptides, aptamers, and small-molecule compounds as delivery vehicles and bind them to target protein degraders (TPDs) or nucleic acid-based therapeutics.

Aptabio Therapeutics Inc. possesses aptamer technology and is applying it to new drug development. Aptamers are nucleic acid molecules that selectively recognize specific proteins; unlike antibodies, they can be chemically synthesized and structurally engineered. They are attracting attention as candidates for next-generation drug delivery platforms because delivery vehicles can be designed to target specific new targets.

Apta-16 is an aptamer-drug conjugate that combines an aptamer with the existing anticancer drug cytarabine. It differs from conventional ADCs in that it delivers the drug by recognizing nucleolin (NCL) on the surface of cancer cells.

An Aptabio Therapeutics Inc. official emphasized, “If Apta-16 demonstrates efficacy and safety in clinical trials, it will demonstrate the potential of Aptabio Therapeutics Inc.’s aptamer technology as a drug delivery method that can replace or complement antibodies,” adding, “This means that not only the value of this single new drug candidate but also the commercial value of the entire aptamer-based drug delivery platform could increase.”

Targeting Simultaneous Resistance to Cytarabine and Venetoclax… Significant Unmet Medical Need

The high

unmet

medical need for relapsed and refractory acute myeloid leukemia (AML) is one of the reasons Apta-16 is drawing attention on the global stage and at major oncology conferences.

AML is an intractable blood cancer for which treatment options are significantly limited if the disease recurs after treatment or if the patient does not respond to existing drugs. According to Aptabio Therapeutics Inc., approximately 40–60% of AML patients experience recurrence, and the median survival period for patients with relapsed or refractory disease is about 6–9 months.

Apta-16 targets resistance to cytarabine and venetoclax. Cytarabine is an anticancer drug that has long been used to treat AML; it acts by relying on the cell membrane transporter “ENT1” and the intracellular activating enzyme “dCK,” and its efficacy can diminish if problems arise in these pathways.

Apta-16 is designed to deliver cytarabine by utilizing nucleorin on the surface of cancer cells. This represents a way to overcome some of the limitations of existing drug delivery pathways. According to the study, in cytarabine-resistant AML cell lines, Apta-16 inhibited cell proliferation at a concentration approximately 50 times lower than that of conventional cytarabine. This demonstrates the potential to improve activity against resistant cells by altering the delivery method of the same drug.

Furthermore, research conducted this year revealed additional evidence that Apta-16 can overcome venetoclax resistance. Venetoclax inhibits the “BCL-2” protein, which aids in cancer cell survival, but it faces resistance issues due to increased expression of another survival protein called “MCL-1.” The study found that nucleorin regulates MCL-1 expression, and a significant improvement in survival was observed in a venetoclax-resistant mouse model following administration of Apta-16 alone.

This demonstrates that Apta-16 not only delivers cytarabine to cancer cells but also has the potential to inhibit cancer cell survival signals. By simultaneously targeting resistance arising from the drug delivery process and resistance stemming from cancer cell survival mechanisms—all with a single candidate compound—the company has secured a unique position and competitive edge.

Aptabio Therapeutics Inc. aims to submit an Investigational New Drug (IND) application for a Phase 1 clinical trial of Apta-16 in South Korea in the fourth quarter of this year, with the goal of administering the first dose to a patient in the first half of 2027. Apta-16 was designated as an orphan drug by the U.S. FDA in 2021.

Since changes in cancer cells and biomarkers in blood cancers can be directly observed through blood and bone marrow tests, it is possible to confirm early signs of efficacy relatively quickly compared to solid tumors. Aptabio Therapeutics Inc. plans to focus on determining whether treatment responses occur in patients who have shown resistance to existing anticancer drugs.

An Aptabio Therapeutics Inc. official stated, “If the clinical trial demonstrates the potential to overcome resistance, discussions regarding global technology licensing will begin in earnest, and the overall commercial value of the Apta-DC platform will increase.”