NMPA Grants ADRX-0405 IND Clearance in Late-Stage Solid/Prostate Tumors

The China National Medical Products Association (NMPA) has granted next-generation antibody drug conjugate (ADC) ADRX-0405 investigational new drug (IND) clearance for the treatment of adult patients with late-stage solid tumors, including metastatic castration-resistant prostate cancer (CRPC), according to a news release from the developer, Adcentrx Therapeutics.¹

Additionally, according to the developers, the clearance enables the inclusion of China-based clinical centers to the ongoing phase 1a/1b trial (NCT06710379) evaluating ADRX-0405 among patients with late-stage solid tumors.

"NMPA's clearance of the ADRX-0405 IND is another important milestone for Adcentrx," Hui Li, PhD, founder and chief executive officer of Adcentrx, said in the release.¹ "This clearance expands our ability to enroll patients in both the US 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."

The first-in-human, open-label, multicenter dose escalation and expansion study is enrolling patients with histologically confirmed advanced/metastatic CRPC, gastric cancer, and non–small cell lung cancer. ² In the phase 1a protocol, patients will receive escalating doses of ADRX-0405 to identify the maximum tolerated dose (MTD), with the recommended dose used in the phase 1b protocol.

The primary end point of the trial is the incidence of adverse effects (AEs). Secondary end points include maximum blood concentration, trough concentration, area under the blood concentration curve, as well as efficacy outcomes including objective response rate, progression-free survival, and overall survival.

ADRX-0405 was developed to target six-transmembrane epithelial antigen of the prostate 1 (STEAP1), which is an overexpressed cell surface protein among prostate cancer and other malignancies with limited expression in healthy tissue. The agent is composed of a humanized IgG1 antibody in tandem with a topoisomerase inhibitor linker-payload through the developer’s i-Conjugation platform. Additionally, payload delivery is enhanced through the platform’s use of a cleavable linker and stable conjugation chemistry.

Preclinical studies have demonstrated the feasibility of ADRX-0405 based on pharmacokinetic, safety, and efficacy data across animal tumor models.

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). They also need to have adequate hematologic, liver, and renal function and an ECOG performance status of 0 to 1. In the phase 1b portion of the trial, patients had histologically confirmed castration-resistant prostate adenocarcinoma only and had an ECOG performance status of up to 2.

Ineligibility criteria for the phase 1 trial included active and uncontrolled central nervous system metastases, significant cardiovascular disease, and a history of a separate malignancy within 3 years of study treatment. Additionally, patients who received anticancer or investigational therapies within 5 elimination half-lives or 14 days, or within 4 weeks for prostate cancer radiopharmaceutical therapies; those with a history of non-infectious interstitial lung disease (ILD) or pneumonitis requiring steroids within 2 years of study enrollment, current ILD/pneumonitis, or suspected ILD/pneumonitis; and those who received systemic antimicrobials for active infection except for antimicrobial prophylaxis were excluded from trial enrollment.

The FDA previously granted orphan drug designation to ADRX-0405 for the treatment of patients with gastric cancer in July 2025.³

Moreover, in an article published in Trends in Cancer, lead author Rohit Singh, PhD, a researcher in the department of Cancer Immunology at the Institute for Cancer Research and Oslo University Hospital in Oslo, Norway, suggested that STEAP1 could emerge as a promising therapeutic target.⁴

“[E]arly results suggest that elevated STEAP1 expression may be associated with more favorable treatment responses, underscoring the potential benefit of refined patient selection criteria,” Singh stated in the publication with study coinvestigator, Jon Amund Kyte, MD, PhD.⁴ “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. In this context, the incorporation of STEAP1-targeted imaging, biomarker-driven enrollment, and combination strategies…may be crucial for optimizing the clinical impact of these therapies.”

References

1. China NMPA grants IND clearance to Adcentrx Therapeutics’ ADRX-0405 STEAP1 ADC for the treatment of late-stage solid tumors, including prostate cancer. News release. Adcentrx Therapeutics. June 9, 2026. Accessed June 9, 2026. https://tinyurl.com/ybt723hw
2. A study of ADRX-0405 in subjects with select advanced solid tumors. ClinicalTrials.gov. Updated April 9, 2025. Accessed June 9, 2026. https://tinyurl.com/kfj7j3pb
3. U.S. FDA grants orphan drug designation to Adcentrx Therapeutics' ADRX 0405 STEAP1 ADC for gastric cancer. News release. Adcentrx Therapeutics. July 8, 2025. Accessed June 9, 2026. https://tinyurl.com/3wsxaej5
4. Singh R, Kyte JA. STEAP1: a promising target in prostate cancer therapy. Trends Cancer. 2025;11(8):722-725. doi:10.1016/j.trecan.2025.05.007