---
title: Trial of BDC-1001 +/- Pertuzumab in Subjects With HER2-Positive Metastatic Breast Cancer
nct_id: NCT05954143
overall_status: TERMINATED
phase: PHASE2
sponsor: Bolt Biotherapeutics, Inc.
study_type: INTERVENTIONAL
primary_condition: Metastatic Breast Cancer
countries: United States, Spain
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT05954143.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT05954143"
ct_last_update_post_date: 2025-11-20
last_seen_at: "2026-05-12T07:34:16.285Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# Trial of BDC-1001 +/- Pertuzumab in Subjects With HER2-Positive Metastatic Breast Cancer

**Official Title:** Phase 2, Multi-Center, Randomized, Open-Label Trial of BDC-1001 as a Single Agent and in Combination With Pertuzumab in Subjects With HER2-Positive Metastatic Breast Cancer Previously Treated With Trastuzumab Deruxtecan

**NCT ID:** [NCT05954143](https://clinicaltrials.gov/study/NCT05954143)

## Key Facts

- **Status:** TERMINATED
- **Why Stopped:** Sponsor Decision
- **Phase:** PHASE2
- **Study Type:** INTERVENTIONAL
- **Target Enrollment:** 11
- **Lead Sponsor:** Bolt Biotherapeutics, Inc.
- **Collaborators:** Hoffmann-La Roche
- **Conditions:** Metastatic Breast Cancer, HER2-positive Breast Cancer
- **Start Date:** 2023-11-30
- **Completion Date:** 2024-09-25
- **CT.gov Last Update:** 2025-11-20

## Brief Summary

This is an open-label, Phase 2 study to evaluate preliminary anti-tumor activity, safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of BDC-1001 administered as a single agent and in combination with pertuzumab in subjects with human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC) previously treated with trastuzumab deruxtecan (Enhertu®).

## Detailed Description

Eligible subjects will be randomly assigned in a 1:1 ratio to receive BDC-1001 as a single agent or BDC-1001 in combination with pertuzumab. Within each treatment arm, a Simon 2-stage design will be applied. Subjects will receive study treatment (i.e., BDC-1001 or BDC-1001 in combination with pertuzumab) for up to 24 months after Cycle 1 Day 1 (C1D1), until disease progression, unacceptable toxicity, or withdrawal for any reason.

Bolt amended the protocol to transition any subjects still receiving BDC-1001 to continue receiving BDC-1001 in the Maintenance Phase. Subjects remaining on BDC-1001 will continue to receive BDC-1001 until a criterion for discontinuation has been met.

## Eligibility

- **Minimum age:** 18 Years
- **Sex:** ALL
- **Healthy Volunteers:** No

```
Key Inclusion Criteria:

* Histologically confirmed adenocarcinoma of the breast that is HER2+ (IHC 3+ or gene amplification by ISH or NGS).
* Have received 2 or more prior lines of anti-HER2-directed therapies, at least 1 in the metastatic setting and including trastuzumab deruxtecan.
* Measurable disease as determined by RECIST v.1.1.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
* Have life expectancy of greater than 12 weeks per the Investigator.
* All subjects must agree to have a biopsy prior to enrollment. If, in the judgment of the Investigator, a biopsy is not safely accessible or clinically feasible an archival tumor tissue sample must be submitted in lieu of a freshly collected specimen.

Key Exclusion Criteria:

* History of severe hypersensitivity to any ingredient of BDC-1001 or pertuzumab.
* Previous treatment with a small molecule TLR7/8 agonist or TLR7/8 agonist that has been conjugated to tumor-targeting antibody such as ISACs within 12 months before starting study treatment.
* Impaired cardiac function or history of clinically significant cardiac disease.
* Human Immunodeficiency virus (HIV) infection, active hepatitis B infection, or hepatitis C infection.
* Central nervous system metastases with the exception of disease that is asymptomatic, clinically stable, and has not required steroids for at least 28 days before starting study treatment.
```

## Arms

- **BDC-1001 Single Agent** (EXPERIMENTAL) — BDC-1001 administered intravenously (IV) every 2 weeks
- **BDC-1001 in Combination With Pertuzumab** (EXPERIMENTAL) — BDC-1001 administered intravenously (IV) every 2 weeks, in combination with pertuzumab administered intravenously (IV) as a fixed non-weight-based dose of 840-mg IV loading dose and then 420-mg IV maintenance dose every 3 weeks.

## Interventions

- **BDC-1001** (DRUG) — BDC-1001 is an immune-stimulating antibody conjugate (ISAC) designed to be delivered systemically (intravenously) and act locally by targeting HER2-expressing tumors and related metastatic disease for destruction by the innate and adaptive immune systems. BDC-1001 consists of an investigational biosimilar of the humanized monoclonal antibody (mAb) trastuzumab that is chemically conjugated to a toll-like receptor (TLR)7/8 agonist (payload) with an intervening non-cleavable, cell membrane impermeable linker.
- **Pertuzumab** (DRUG) — Pertuzumab is a monoclonal antibody that targets HER2 and prevents dimerization of HER2 with other members of the HER family (HER1, HER3, and HER4), thereby blocking ligand-activated downstream signaling.

## Primary Outcomes

- **Objective Response Rate (ORR) Per RECIST v1.1 as Assessed by Investigator** _(time frame: Up to approximately 1 year)_ — Objective Response Rate (ORR) was defined as the proportion of participants with best overall response of confirmed Complete Response (CR) or Partial Response (PR) as determined by the treating Investigator using RECIST v1.1 criteria.

## Secondary Outcomes

- **Duration of Response (DOR) Per RECIST v1.1 as Assessed by Investigator** _(time frame: Up to approximately 1 year)_
- **Disease Control Rate (DCR) Per RECIST v1.1 as Assessed by Investigator** _(time frame: Up to approximately 1 year)_
- **Progression-Free Survival (PFS) Per RECIST 1.1 as Assessed by Investigator** _(time frame: Up to approximately 1 year)_
- **Overall Survival (OS)** _(time frame: Up to approximately 1 year)_
- **Number of Participants With at Least 1 Treatment Emergent Adverse Event (TEAE)** _(time frame: Continuously from first dose of study treatment through end of treatment and Safety Follow-Up. Up to approximately 1 year)_
- **Number of Participants Who Had Any Treatment Emergent Adverse Event (TEAE) Related to Study Treatment** _(time frame: Continuously from first dose of study treatment through end of treatment and Safety Follow-Up. Up to approximately 1 year.)_
- **Number of Participants With Any Treatment Emergent Serious Adverse Event (SAE) Related to Study Treatment** _(time frame: Continuously from first dose of study treatment through end of treatment and Safety Follow-Up. Up to approximately 1 year.)_

## Locations (4)

- City of Hope, Irvine, California, United States
- Memorial Sloan Kettering Cancer Center, New York, New York, United States
- Virginia Cancer Specialists, Arlington, Virginia, United States
- Hospital Universitario 12 de Octubre, Madrid, Spain

## Recent Field Changes (last 30 days)

- `status.overallStatus` — added _(2026-05-12)_
- `status.whyStopped` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.phases` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `outcomes.secondary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_
- `sponsor.collaborators` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `locations.city of hope|irvine|california|united states` — added _(2026-05-12)_
- `locations.memorial sloan kettering cancer center|new york|new york|united states` — added _(2026-05-12)_
- `locations.virginia cancer specialists|arlington|virginia|united states` — added _(2026-05-12)_
- `locations.hospital universitario 12 de octubre|madrid||spain` — added _(2026-05-12)_

---

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*Source data (authoritative): https://clinicaltrials.gov/study/NCT05954143*  
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