China NMPA Grants IND Clearance to Adcentrx's STEAP1-Targeting ADC ADRX-0405 for Late-Stage Solid Tumors
核心洞察
China's NMPA has cleared Adcentrx Therapeutics (搜索)' IND application for ADRX-0405, a first-in-class STEAP1 (搜索)-targeting antibody-drug conjugate, enabling inclusion of China-based clinical centers in the ongoing Phase 1a/1b trial.
The open-label, multicenter study is enrolling patients with metastatic castration-resistant prostate cancer (搜索), gastric cancer (搜索), and non-small cell lung cancer (搜索), with the Phase 1a portion expected to complete by Q4 2026.
ADRX-0405 utilizes Adcentrx's i-Conjugation platform featuring a cleavable linker and stable conjugation chemistry with a drug-antibody ratio of 8 to maximize payload delivery to solid tumors.
Adcentrx Therapeutics (搜索) announced on June 8, 2026 that the China National Medical Products Administration (NMPA) has granted Investigational New Drug (IND) clearance for ADRX-0405, a potential first-in-class, next-generation antibody-drug conjugate (ADC) targeting STEAP1 (搜索). The regulatory milestone enables the San Diego and Shanghai-based biotechnology company to include China-based clinical centers in its ongoing Phase 1a/1b trial (NCT06710379), broadening geographic representation and accelerating patient enrollment in the study evaluating patients with late-stage solid tumors.
"NMPA's clearance of the ADRX-0405 IND is another important milestone for Adcentrx," said Hui Li, Ph.D., Founder and Chief Executive Officer of Adcentrx. "This clearance expands our ability to enroll patients in both the U.S. and China, broadening geographic representation and allowing us to generate clinical data across more diverse patient populations. This enables ADRX-0405 to address important unmet needs across multiple tumor types."
STEAP1 (搜索): An Emerging Therapeutic Target
ADRX-0405 targets six-transmembrane epithelial antigen of the prostate 1 (STEAP1 (搜索)), a cell surface protein that is overexpressed in prostate cancer and certain other malignancies, with limited expression in healthy tissue. The therapeutic rationale for targeting STEAP1 has gained increasing attention in the oncology community. In an article published in Trends in Cancer, lead author Rohit Singh, Ph.D., a researcher in the Department of Cancer Immunology at the Institute for Cancer Research and Oslo University Hospital, and co-investigator Jon Amund Kyte, M.D., Ph.D., suggested that STEAP1 could emerge as a promising therapeutic target.
"[E]arly results suggest that elevated STEAP1 (搜索) expression may be associated with more favorable treatment responses, underscoring the potential benefit of refined patient selection criteria," Singh stated in the publication. The authors also noted that "despite these promising developments, challenges remain. Immune-mediated AEs, such as musculoskeletal inflammation, including myalgia and arthralgia, and limited clinical benefit observed in the earlier trials warrant further investigation."
i-Conjugation Platform and ADC Design
ADRX-0405 is composed of a humanized IgG1 antibody coupled with a novel topoisomerase inhibitor linker-payload through Adcentrx's innovative i-Conjugation technology platform. The platform utilizes a cleavable linker and stable conjugation chemistry to enhance payload delivery, enabling a highly stable ADC with a drug-antibody ratio of eight (DAR 8) to maximize payload delivery to solid tumors. Preclinical studies have demonstrated favorable pharmacokinetics, safety profile, and significant efficacy across multiple animal tumor models.
Phase 1a/1b Trial Design
The first-in-human Phase 1a/1b clinical trial of ADRX-0405 is an open-label, multicenter dose escalation and dose expansion study enrolling patients with select advanced solid tumors, including metastatic castration-resistant prostate cancer (搜索) (mCRPC), gastric cancer (搜索), and non-small cell lung cancer (搜索) (NSCLC).
In the Phase 1a portion, patients will receive escalating doses of ADRX-0405 to identify the maximum tolerated dose (MTD), with the recommended dose subsequently used in the Phase 1b protocol. The primary endpoint of the trial is the incidence of adverse effects (AEs). Secondary endpoints include maximum blood concentration, trough concentration, area under the blood concentration curve, as well as efficacy outcomes including objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).
Eligible patients in the Phase 1 protocol must have measurable disease per RECIST v1.1 guidelines or evaluable disease per the Prostate Cancer Working Group 3 (PCWG3) criteria, adequate hematologic, liver, and renal function, and an ECOG performance status of 0 to 1. For the Phase 1b portion, patients must have histologically confirmed castration-resistant prostate adenocarcinoma and an ECOG performance status of up to 2.
Key exclusion criteria include active and uncontrolled central nervous system metastases, significant cardiovascular disease, history of a separate malignancy within 3 years of study treatment, history of non-infectious interstitial lung disease (ILD) or pneumonitis requiring steroids within 2 years of study enrollment, current or suspected ILD/pneumonitis, and receipt of systemic antimicrobials for active infection. Patients who received anticancer or investigational therapies within 5 elimination half-lives or 14 days (or within 4 weeks for prostate cancer radiopharmaceutical therapies) are also ineligible.
The company anticipates completing the Phase 1a portion of the trial by the fourth quarter of 2026.
Regulatory Context
The FDA previously granted orphan drug designation to ADRX-0405 for the treatment of patients with gastric cancer (搜索) in July 2025. The NMPA clearance now positions Adcentrx to generate clinical data across more diverse patient populations spanning both U.S. and China-based sites, potentially accelerating the development timeline for this STEAP1 (搜索)-targeted ADC across multiple tumor types with significant unmet medical need.