National Cancer Institute (NCI)
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. Trastuzumab deruxtecan is in a class of medications called antibody-drug conjugates. It is composed of a monoclonal antibody, called trastuzumab, linked to a chemotherapy drug, called deruxtecan. Trastuzumab attaches to HER2 positive tumor cells in a targeted way and delivers deruxtecan to kill them. Giving pidnarulex in combination with trastuzumab deruxtecan may be safe, tolerable and/or effective in treating patients with metastatic, unresectable, or locally advanced HER2-expressing breast cancer or other solid tumors.
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
Biopsy Procedure
Biospecimen Collection
Echocardiography Test
Multigated Acquisition Scan
Pidnarulex
Radiologic Imaging Procedure
Trastuzumab Deruxtecan
PHASE1
PRIMARY OBJECTIVES: I. To determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of CX-5461 (pidnarulex) when used in combination with trastuzumab deruxtecan (T-DXd) in patients with human epidermal growth factor receptor 2 (HER2)-low breast cancer, hormone receptor (HR)-positive HER2-ultralow breast cancer or HER2-positive (immunohistochemistry \[IHC\] 3+) solid tumors. (Dose escalation primary objective) II. To evaluate safety and tolerability of the combination of CX-5461 (pidnarulex) with T-DXd at the RP2D in patients with HER2-low breast cancer and HR-positive HER2-ultralow breast cancer. (Dose expansion primary objective) SECONDARY OBJECTIVES: I. To observe and record anti-tumor activity. II. To evaluate the plasma pharmacokinetic (PK) profiles of CX-5461 (pidnarulex) and T-DXd when administered in combination. III. To determine markers of deoxyribonucleic acid (DNA) damage response (DDR) in tumor specimens at baseline and on-treatment in patients with HER2-low and ultralow breast cancer in the dose expansion cohort (pharmacodynamic \[PD\] objective). OUTLINE: This is a dose-escalation study of pidnarulex followed by a dose-expansion study. Patients receive pidnarulex intravenously (IV) over 60 minutes on day 8 of each cycle and T-DXd IV over 30-90 minutes on day 1 of each cycle. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. Patients also undergo echocardiography (ECHO) or multigated acquisition scan (MUGA), collection of blood samples, and radiologic imaging throughout the trial. Patients may also undergo biopsy throughout the trial. After completion of study treatment, patients are followed up at 30 days and then for 3 years.
| Study Type : | INTERVENTIONAL |
| Estimated Enrollment : | 36 participants |
| Masking : | NONE |
| Primary Purpose : | TREATMENT |
| Official Title : | Phase 1b Study of Pidnarulex and Trastuzumab Deruxtecan in Patients With HER2 Expressing Solid Tumors |
| Actual Study Start Date : | 2026-10-05 |
| Estimated Primary Completion Date : | 2028-01-10 |
| Estimated Study Completion Date : | 2028-01-10 |
Information not available for Arms and Intervention/treatment
| Ages Eligible for Study: | 18 Years |
| Sexes Eligible for Study: | ALL |
| Accepts Healthy Volunteers: |
Want to participate in this study, select a site at your convenience, send yourself email to get contact details and prescreening steps.
RECRUITING
Dana-Farber - Harvard Cancer Center LAO
Boston, Massachusetts, United States, 02115