Breast CancerPhase 1NCT05654532
Study of AC699 in Patients With Estrogen Receptor Positive/Human Epidermal Growth Factor Receptor 2 Negative (ER+/HER2-) Locally Advanced or Metastatic Breast Cancer
A Phase 1 study testing AC699 in people with Breast Cancer, run by Accutar Biotechnology Inc at 9 sites in United States.
Trial summary
This clinical trial is evaluating a drug called AC699 in participants with estrogen receptor positive/human epidermal growth factor 2 negative (ER+/HER2-) locally advanced or metastatic breast cancer. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Breast Cancer
- What is being tested?
- AC699
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 9 sitesUnited States
- Study dates
- 29 Dec 2022to 31 May 2026
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
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
- Signed written informed consent (ICF)
- Adult male and female participants, at least 18 years-of-age at the time of signature of the ICF
- Female participants must be postmenopausal
- Confirmed diagnosis of advanced, unresectable, and/or metastatic breast cancer following disease progression on standard treatment, or for whom no therapy of proven efficacy exists, or who are not amenable to standard therapies
- Histologically and/or cytologically confirmed diagnosis of estrogen-receptor positive (ER+) human epidermal growth factor 2 negative (HER2-) breast cancer
- Must have received at least 2 prior endocrine or at least 1 prior line of endocrine therapy if combined with CDK4/6 inhibitor
Show all 10Show fewer
- Prior chemotherapy is not required, but up to 3 prior regimens of cytotoxic chemotherapy will be allowed in the locally advanced/ metastatic setting
- At least 1 measurable lesion according to Response Evaluation Criteria in Solid Tumors (RECIST) Version 1.1 (Appendix B) or at least 1 predominantly lytic bone lesion in the absence of measurable disease
- Acceptable organ and hematologic function at baseline
- Life expectancy ≥12 weeks after the start of the treatment
Who cannot join
- Treatment with any of the following:
- Any cytotoxic chemotherapy, investigational agents or other anti-cancer drugs for the treatment of locally advanced or metastatic breast cancer within 14 days prior to the first administration of AC699
- Radiation therapy within 14 days prior to first study drug administration that did not resolve to tolerable toxicity, or prior irradiation to >25% of bone marrow. Prior palliative radiotherapy to metastatic lesion(s) is permitted, provided it has been completed 7 days prior to study enrollment and no clinically significant toxicities are expected (e.g., mucositis, esophagitis).
- Major surgery within 21 days prior to the first study drug administration (exception: participants may enroll if fully recovered or without intolerable or clinically significant adverse effects but at least 14 days must have elapsed between major surgery and first study drug administration)
- Known symptomatic brain metastases requiring the use of systemic corticosteroids ≥10 mg/day prednisone or equivalents. Asymptomatic and treated, or asymptomatic untreated brain metastases are allowed as long as participants are clinically stable. Stable doses of anticonvulsants are allowed.
- Any condition that impairs a participant's ability to swallow whole pills. Impairment of gastrointestinal function (GI) or GI disease or other condition at baseline that will interfere significantly with the absorption, distribution, or metabolism of AC699.
Trial locations and contacts
9 sites in 1 country.
9 sites in 1 country
United States9 sites
Site 08
Denver, Colorado, 80218
Site 03
Houston, Texas, 77030
Site 01
Nashville, Tennessee, 37203
Site 05
Norfolk, Virginia, 23502
Site 07
Orlando, Florida, 32746
Site 06
Rockville, Maryland, 21044
Site 09
San Antonio, Texas, 78240
Site 02
Sarasota, Florida, 34232
Site 04
Vancouver, Washington, 98684
About this study
Official title: A Phase I Clinical Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Preliminary Anti-Tumor Activity of AC699 in Patients With Estrogen Receptor Positive/Human Epidermal Growth Factor Receptor 2 Negative (ER+/HER2-) Locally Advanced or Metastatic Breast Cancer
This clinical trial is evaluating a drug called AC699 in participants with estrogen receptor positive/human epidermal growth factor 2 negative (ER+/HER2-) locally advanced or metastatic breast cancer. The main goals of this study are to:
- Identify the recommended dose of AC699 that can be given safely to participants
- Evaluate the safety profile of AC699
- Evaluate the pharmacokinetics of AC699
- Evaluate the effectiveness of AC699
Read the detailed description
This study is a Phase I, first-in-human, open-label dose-escalation study of AC699, an orally bioavailable estrogen receptor degrader, given as a single agent.
- Conditions
- Breast Cancer
- Being tested
- AC699
- Keywords
- Breast Cancer, Estrogen receptor-positive breast cancer, ER positive, ER+, Human epidermal growth factor receptor 2 negative, HER2 negative breast cancer, HER2-, AC699, Metastatic breast cancer, MBC, Locally advanced breast cancer, ER chimeric degrader, ER degrader
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AC699Drug
Participants will receive AC699 orally daily in 28-day cycles.
| Study group | Role | What they receive |
|---|---|---|
| AC699 Dose Escalation | Experimental | Participants will receive an assigned dose of AC699 monotherapy during dose escalation.
One cycle is defined as 28 days. Receives: Drug: AC699 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of dose limiting toxicities (DLTs) from AC699 monotherapy
Measured: First 28 days of treatment. Cycles are 28 days.
Incidence of treatment-emergent adverse events (TEAEs) and clinically significant Grade 3 or higher lab abnormalities following administration of AC699
Measured: Approximately 18 months.
Secondary outcomes (10)
Objective response rate (ORR) to assess the anti-tumor activity of AC699
Measured: Approximately 18 months.
Clinical Benefit Rate (CBR) to assess the anti-tumor activity of AC699 using RECIST 1.1
Measured: Approximately 18 months.
Duration of Response (DOR) to assess the anti-tumor activity of AC699 using RECIST 1.1
Measured: Approximately 18 months.
Disease Control Rate (DCR) to assess the anti-tumor activity of AC699 using RECIST 1.1
Measured: Approximately 18 months.
Progression Free Survival (PFS) to assess the anti-tumor activity of AC699 using RECIST 1.1
Measured: Approximately 18 months.
Pharmacokinetic Analysis: Area under the concentration-time curve over the dosing interval (AUC(0-infinity))
Measured: Up to approximately 28 weeks
Pharmacokinetic Analysis: Area under the concentration-time curve over the dosing interval (AUC(0-tau))
Measured: Up to approximately 28 weeks
Pharmacokinetic Analysis: Maximum plasma concentration (Cmax)
Measured: Up to approximately 28 weeks
Pharmacokinetic Analysis: Time to maximum plasma concentration (tmax)
Measured: Up to approximately 28 weeks
Pharmacokinetic Analysis: Terminal elimination half-life (t1/2)
Measured: Up to approximately 28 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Dec 2022
- Study start29 Dec 2022
- Primary completion31 Mar 2026 (estimated)
- Study completion31 May 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for 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 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Accutar Biotechnology Inc
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05654532
- Sponsor's protocol ID
- AC699-001
- Status last verified
- Sep 2025
- First submitted
- 8 Dec 2022
- Last updated
- 30 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Hamilton E, Layman RM, Cosgrove D, Danso M, Zhang H, He W, Kim SY, Fan J, Patel MR. ER degradation for ER+/HER2- advanced or metastatic breast cancer: a phase 1 trial. Nat Commun. 2025 Dec 17;17(1):796. doi: 10.1038/s41467-025-67485-y.
PubMed 41407710
Study at a glance
From the registry record, last updated by the sponsor on 30 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase I Clinical Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Preliminary Anti-Tumor Activity of AC699 in Patients With Estrogen Receptor Positive/Human Epidermal Growth Factor Receptor 2 Negative (ER+/HER2-) Locally Advanced or Metastatic Breast Cancer
- ClinicalTrials.gov ID
- NCT05654532
- Acronym / sponsor ID
- AC699-001
- Conditions
- Breast Cancer
- Keywords
- Breast Cancer, Estrogen receptor-positive breast cancer, ER positive, ER+, Human epidermal growth factor receptor 2 negative, HER2 negative breast cancer, HER2-, AC699
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Accutar Biotechnology IncIndustry (pharma, biotech, devices)
- Study start
- 29 Dec 2022 (actual)
- Primary completion
- 31 Mar 2026 (estimated)
- Study completion
- 31 May 2026 (estimated)
- First posted
- 16 Dec 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This clinical trial is evaluating a drug called AC699 in participants with estrogen receptor positive/human epidermal growth factor 2 negative (ER+/HER2-) locally advanced or metastatic breast cancer. The main goals of this study are to:
- Identify the recommended dose of AC699 that can be given safely to participants
- Evaluate the safety profile of AC699
- Evaluate the pharmacokinetics of AC699
- Evaluate the effectiveness of AC699
Detailed description
This study is a Phase I, first-in-human, open-label dose-escalation study of AC699, an orally bioavailable estrogen receptor degrader, given as a single agent.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| AC699 Dose Escalation | Experimental | Drug: AC699Participants will receive an assigned dose of AC699 monotherapy during dose escalation. One cycle is defined as 28 days. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- Signed written informed consent (ICF)
- Adult male and female participants, at least 18 years-of-age at the time of signature of the ICF
- Female participants must be postmenopausal
- Confirmed diagnosis of advanced, unresectable, and/or metastatic breast cancer following disease progression on standard treatment, or for whom no therapy of proven efficacy exists, or who are not amenable to standard therapies
- Histologically and/or cytologically confirmed diagnosis of estrogen-receptor positive (ER+) human epidermal growth factor 2 negative (HER2-) breast cancer
Key exclusion criteria (6 listed)
- Treatment with any of the following:
- Known symptomatic brain metastases requiring the use of systemic corticosteroids ≥10 mg/day prednisone or equivalents. Asymptomatic and treated, or asymptomatic untreated brain metastases are allowed as long as participants are clinically stable. Stable doses of anticonvulsants are allowed.
- Any condition that impairs a participant's ability to swallow whole pills. Impairment of gastrointestinal function (GI) or GI disease or other condition at baseline that will interfere significantly with the absorption, distribution, or metabolism of AC699.
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 |
|---|---|---|
| AC699Participants will receive AC699 orally daily in 28-day cycles. | Drug | AC699 Dose Escalation |
Primary outcome
Incidence of dose limiting toxicities (DLTs) from AC699 monotherapy
Time frame: First 28 days of treatment. Cycles are 28 days.
Incidence of treatment-emergent adverse events (TEAEs) and clinically significant Grade 3 or higher lab abnormalities following administration of AC699
Time frame: Approximately 18 months.
10 secondary outcomes
Objective response rate (ORR) to assess the anti-tumor activity of AC699
Time frame: Approximately 18 months.
Clinical Benefit Rate (CBR) to assess the anti-tumor activity of AC699 using RECIST 1.1
Time frame: Approximately 18 months.
Duration of Response (DOR) to assess the anti-tumor activity of AC699 using RECIST 1.1
Time frame: Approximately 18 months.
Disease Control Rate (DCR) to assess the anti-tumor activity of AC699 using RECIST 1.1
Time frame: Approximately 18 months.
Progression Free Survival (PFS) to assess the anti-tumor activity of AC699 using RECIST 1.1
Time frame: Approximately 18 months.
Pharmacokinetic Analysis: Area under the concentration-time curve over the dosing interval (AUC(0-infinity))
Time frame: Up to approximately 28 weeks
Pharmacokinetic Analysis: Area under the concentration-time curve over the dosing interval (AUC(0-tau))
Time frame: Up to approximately 28 weeks
Pharmacokinetic Analysis: Maximum plasma concentration (Cmax)
Time frame: Up to approximately 28 weeks
Pharmacokinetic Analysis: Time to maximum plasma concentration (tmax)
Time frame: Up to approximately 28 weeks
Pharmacokinetic Analysis: Terminal elimination half-life (t1/2)
Time frame: Up to approximately 28 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Sep 2025.
- Derived from this study: PubMed 41407710Hamilton E, Layman RM, Cosgrove D, Danso M, Zhang H, He W, Kim SY, Fan J, Patel MR. ER degradation for ER+/HER2- advanced or metastatic breast cancer: a phase 1 trial. Nat Commun. 2025 Dec 17;17(1):796. doi: 10.1038/s41467-025-67485-y.
- 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.
The record lists no contact. Use the official record to reach the sponsor.
9 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing AC699 in people with Breast Cancer, run by Accutar Biotechnology Inc at 9 sites in United States.
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 10 inclusion and 6 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: under way, not looking for participants, as of the sponsor's last update on 30 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 9 sites in United States. 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 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
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?
Incidence of dose limiting toxicities (DLTs) from AC699 monotherapy (time frame: First 28 days of treatment. Cycles are 28 days.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05654532, which also lists 1 linked publication.
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 30 Sep 2025.