Metastatic Breast CancerPhase 2NCT05954143
Trial of BDC-1001 +/- Pertuzumab in Subjects With HER2-Positive Metastatic Breast Cancer
A Phase 2 study testing BDC-1001 and Pertuzumab in people with Metastatic Breast Cancer and HER2-positive Breast Cancer, run by Bolt Biotherapeutics, Inc. at 4 sites in 2 countries.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Metastatic Breast Cancer, HER2-positive Breast Cancer
- What is being tested?
- BDC-1001 and Pertuzumab
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 11 participants
- Where
- 4 sitesin 2 countries
- Study dates
- 30 Nov 2023to 25 Sep 2024
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
4 sites in 2 countries.
4 sites in 2 countries
United States3 sites
Virginia Cancer Specialists
Arlington, Virginia, 22205
City of Hope
Irvine, California, 92618
Memorial Sloan Kettering Cancer Center
New York, New York, 10065
About this study
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
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®).
Read the 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.
- Being tested
- BDC-1001, Pertuzumab
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
BDC-1001Drug
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.
PertuzumabDrug
Also called Perjeta®
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.
| Study group | Role | What they receive |
|---|---|---|
| BDC-1001 Single Agent | Experimental | BDC-1001 administered intravenously (IV) every 2 weeks Receives: Drug: BDC-1001 |
| 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. Receives: Drug: BDC-1001; Drug: Pertuzumab |
What is being measured
The primary outcome is the main question the study is designed to answer.
Objective Response Rate (ORR) Per RECIST v1.1 as Assessed by Investigator
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.
Measured: Up to approximately 1 year
Secondary outcomes (7)
Duration of Response (DOR) Per RECIST v1.1 as Assessed by Investigator
Duration of Response (DOR) was calculated for participants who achieved confirmed CR or PR. For such participants, DOR is defined as the duration from the start date of CR or PR (whichever response status is observed first) and subsequently confirmed, to the earliest of documented date of PD per RECIST v 1.1 or death.
Of the 8 participants with response assessments, there were no participants with PR or CR. Because there were no responses of PR or CR, the DOR cannot be calculated.
Measured: Up to approximately 1 year
Disease Control Rate (DCR) Per RECIST v1.1 as Assessed by Investigator
Disease Control Rate (DCR) was the proportion of participants who achieved confirmed Complete Response (CR), Partial Response (PR), or Stable Disease (SD) lasting 23 or more weeks following the first dose of study treatment.
Measured: Up to approximately 1 year
Progression-Free Survival (PFS) Per RECIST 1.1 as Assessed by Investigator
Progression-free survival (PFS) was defined as the duration from the date of first study treatment administration (Cycle 1 Day 1) to the earliest date of documented PD per RECIST v1.1 or death. A death was considered a PFS event.
Measured: Up to approximately 1 year
Overall Survival (OS)
Overall Survival (OS) was defined as the duration from the date of first study treatment administration to the date of death, irrespective of cause.
Measured: Up to approximately 1 year
Number of Participants With at Least 1 Treatment Emergent Adverse Event (TEAE)
Treatment Emergent Adverse Events (TEAE) was defined as any AE that started on or after the first administration of study treatment. TEAEs were graded according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0.
Measured: 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
Treatment Emergent Adverse Events (TEAE) was defined as any AE that started on or after the first administration of study treatment. TEAEs were graded according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0.
Measured: 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
Treatment Emergent Adverse Events (TEAE) was defined as any AE that started on or after the first administration of study treatment. TEAEs were graded according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0. A Serious Adverse Event (SAE) was defined as an AE event that resulted in death, was life-threatening, required or prolongs hospitalization, caused persistent or significant disability or incapacity, resulted in congenital anomalies or birth defects, or was an important medical event.
Measured: Continuously from first dose of study treatment through end of treatment and Safety Follow-Up. Up to approximately 1 year.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Jul 2023
- Study start30 Nov 2023
- Primary completion20 Sep 2024
- Study completion25 Sep 2024
Why it stopped: Sponsor Decision
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Metastatic Breast CancerStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- Bolt Biotherapeutics, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Hoffmann-La Roche
- Responsible party
- Sponsor
- Investigators
- Bolt Clinical Development, Study director, Bolt Biotherapeutics
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05954143
- Sponsor's protocol ID
- BBI-20231001
- Status last verified
- Aug 2025
- First submitted
- 23 Jun 2023
- Last updated
- 20 Nov 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- 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
- ClinicalTrials.gov ID
- NCT05954143
- Acronym / sponsor ID
- BBI-20231001
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Sponsor Decision
- Enrolment
- 11 participants (actual)
- Lead sponsor
- Bolt Biotherapeutics, Inc.Industry (pharma, biotech, devices)
- Collaborators
- Hoffmann-La Roche
- Study start
- 30 Nov 2023 (actual)
- Primary completion
- 20 Sep 2024 (actual)
- Study completion
- 25 Sep 2024 (actual)
- First posted
- 20 Jul 2023 (actual)
- Results
- Posted 20 Nov 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| BDC-1001 Single Agent | Experimental | Drug: BDC-1001BDC-1001 administered intravenously (IV) every 2 weeks |
| BDC-1001 in Combination With Pertuzumab | Experimental | Drug: BDC-1001, Drug: PertuzumabBDC-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. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- 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.
Key exclusion criteria (5 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| BDC-1001BDC-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. | Drug | BDC-1001 Single Agent, BDC-1001 in Combination With Pertuzumab |
| PertuzumabAlso: Perjeta®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. | Drug | BDC-1001 in Combination With Pertuzumab |
Primary outcome
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.
7 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.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Nov 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Bolt Clinical Development study director
Bolt Biotherapeutics
4 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing BDC-1001 and Pertuzumab in people with Metastatic Breast Cancer and HER2-positive Breast Cancer, run by Bolt Biotherapeutics, Inc. at 4 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 20 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in United States, Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 20 Nov 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Objective Response Rate (ORR) Per RECIST v1.1 as Assessed by Investigator (time frame: Up to approximately 1 year). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Nov 2025.