Therapex showcases competitive edge with DAC-based preclinical results
Therapex, which has demonstrated clinical capabilities with small molecules, is now expanding into degrader antibody conjugates (DACs). Leveraging its experience in small molecule development, the company is aiming to identify a target protein degrader (TPD) and establish a new drug pipeline.
As part of this transition from small molecules to DACs, Therapex is broadening its drug development scope to target a variety of cancers, including both solid tumors such as lung cancer and hematologic malignancies.
At the center of this strategic expansion is CEO Koo Lee, who brings more than 30 years of industry experience from LG Chem and biotech startups. Since joining Therapex (formerly Interpark Bio) in 2021, Lee has spearheaded the clinical entry of the lung cancer pipeline TRX-221 and consolidated the company's efforts around discovering new drug candidates. Within just over four years, the company has achieved both clinical advancement and the identification of new pipelines. Korea Biomedical Review interviewed CEO Lee to learn more about the company’s development roadmap, including updates on its DAC-based pipeline TRX-214.
TRX-214 unveiled at AACR 2025, poised to compete with Orum Therapeutics
Following the clinical entry of its small molecule-based TRX-221 for lung cancer, Therapex moved quickly to secure its next pipeline. The company focused on a TPD-like molecule glue degrader (MGD), believing it to be the best avenue to apply its core small molecule R&D strengths. Though initially a basic research initiative, it has gained momentum with support from the Korea Drug Development Fund (KDDF).
“Based on our core competency in medicinal chemistry, we boldly initiated the DAC project in early 2023,” said CEO Lee. “Upon analyzing existing small molecule TPD drugs, we concluded that they have certain limitations in efficacy and safety.” He added, “Considering future growth potential, we expanded into the TPD modality. Our conviction about DACs was further reinforced by Orum Therapeutics’ global technology transfer.”
TRX-214 is a DAC-based drug candidate composed of an MGD targeting GSPT1, used as the payload, and conjugated to a CD33 monoclonal antibody. GSPT1 regulates the final step of intracellular protein synthesis.
Multiple studies have reported GSPT1 overexpression in hematologic cancer cell lines, encouraging attempts to develop anticancer drugs using MGDs that degrade GSPT1. One such drug is ORM-6151, which Orum Therapeutics licensed to BMS. As a later entrant, Therapex has gathered preclinical data to compare with existing pipelines.
“TRX-214 showed significant differences in Dmax (maximum degradation rate) and DC50 (drug concentration for 50% degradation), key indicators of GSPT1 degradation activity, compared to ORM-6151,” said Lee. “We also developed and evaluated Venclexta (venetoclax)-resistant AML cells, and TRX-214 demonstrated consistent anticancer activity even in these resistant cells.”
“To extend our preclinical data to AML patient samples, we are conducting collaborative research with Professor Cho Byung-sik’s team at The Catholic University of Korea Seoul St. Mary's Hospital. This includes patient-derived xenograft (PDX) model experiments using bone marrow samples from relapsed/refractory AML patients,” Lee added.
“These results are expected in the second half of this year and are anticipated to strengthen the foundation for validating efficacy and feasibility before clinical entry.”
Final candidate expected by end of year, licensing prior to clinical trials
Therapex does not fixate on the “first-in-class” label. The company’s top priority is to develop drugs that can be used effectively in clinical settings. Following this strategy, Therapex has identified preliminary candidates in just over two years.
“We have identified preliminary candidates and aim to select a final development candidate by the end of this year,” Lee said. “To achieve this, we are fully leveraging our in-house medicinal chemistry and biological evaluation capabilities, as well as external collaboration networks.”
Therapex plans to move swiftly through preclinical development and pursue technology transfer before entering clinical trials. Given the significantly higher costs associated with DAC-based drug development compared to small molecules, the company is particularly focused on achieving licensing at the preclinical stage.
“We are doing everything we can to generate differentiated data compared to competitors to enable licensing before entering preclinical development,” said Lee. “Throughout the TRX-214 development process, we are clearly defining our differentiation across medicinal chemistry, pharmacology, and safety. From candidate selection to the entire drug development cycle, we are always keeping commercialization potential in mind.”
Founded in 2020, Therapex is a subsidiary of Gradiant Corp. (formerly Interpark) and is focused on developing novel anticancer drugs. The company is currently conducting a phase 1 clinical trial for TRX-221, its fourth-generation EGFR mutation-targeted lung cancer therapy.