Testing the Safety of the Combination of Anti-Cancer Drugs CX-5461 (Pidnarulex) and Trastuzumab Deruxtecan (T-DXd) for Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Solid Tumors and Breast Cancer

Summary

This phase I trial tests the safety, side effects, and best dose of pidnarulex in combination with trastuzumab deruxtecan in treating patients with breast cancer and other solid tumors that express varying levels of a protein called HER2 and that has spread from where it first started (primary site) to other places in the body (metastatic), that cannot be removed by surgery (unresectable), or that has spread to nearby tissue or lymph nodes (locally advanced). Pidnarulex is an enzyme inhibitor that causes cell death and prevents tumor cell growth.

Shortened from the sponsor's brief summary. View official record on ClinicalTrials.gov

Conditions studied

• Anatomic Stage III Breast Cancer AJCC v8
• Anatomic Stage IV Breast Cancer AJCC v8
• Invasive Breast Carcinoma
• Locally Advanced Breast Carcinoma
• Metastatic Breast Carcinoma
• Metastatic HER2-Low Breast Carcinoma
• Metastatic HER2-Positive Breast Carcinoma
• Metastatic Hormone Receptor-Positive Breast Carcinoma
• Metastatic Malignant Solid Neoplasm
• Metastatic Triple-Negative Breast Carcinoma
• Unresectable Breast Carcinoma
• Unresectable HER2-Low Breast Carcinoma
• Unresectable HER2-Positive Breast Carcinoma
• Unresectable Hormone Receptor-Positive Breast Carcinoma
• Unresectable Malignant Solid Neoplasm
• Unresectable Triple-Negative Breast Carcinoma

Eligibility basics and study details

Study type

Interventional

Phase

Phase 1

Ages

18 years and older

Sex

All

Healthy volunteers

Not accepted

Sponsor

National Cancer Institute (NCI)

Last updated on ClinicalTrials.gov

July 13, 2026

These are the basic criteria only. The full inclusion and exclusion criteria are on the official record, and the study team decides who can take part.

US recruiting sites