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Advanced Breast CancerPhase 2SERENA-1bNCT07427394

Study to Evaluate the Safety and Tolerability of Camizestrant in Combination With Atirmociclib in Women With Advanced Breast Cancer

A Phase 2 study testing Camizestrant and Atirmociclib in people with Advanced Breast Cancer, run by AstraZeneca at 6 sites in 2 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

A study to investigate camizestrant in combination with atirmociclib in participants with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer previously treated with a cyclin dependent kinase 4/6 (CDK4/6) inhibitor. Read more about this study

Who is it for?
Ages 18 years and older, women only
Conditions the study is for
Advanced Breast Cancer
What is being tested?
Camizestrant and Atirmociclib
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
24 participants
Where
6 sitesin 2 countries
Study dates
6 May 2026to 28 Dec 2027
Phase
Phase 2
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
  • Women only
  • No healthy volunteers
  • Adult, Older adult

Main Inclusion Criteria:

  • Participants with advanced adenocarcinoma of the breast and must have received prior adequate therapy in accordance with local practice for their tumor type and stage of disease.
  • Metastatic or locoregionally recurrent disease and radiological or objective evidence of progression on or after the last systemic therapy prior to starting investigational medicinal products.
  • Eastern cooperative oncology group (ECOG)/World Health Organization (WHO) performance status 0 to 1, and a minimum life expectancy of 12 weeks.
  • At least one lesion that is measurable and/or non-measurable, as per RECIST 1.1 and that can be accurately assessed at baseline and is suitable for repeated assessment by computed tomography (CT), magnetic resonance imaging (MRI), or plain X-ray, or clinical examination.
  • Menopausal status
  • Pre-menopausal women must start GnRH agonist therapy at least 4 weeks before study treatment and continue throughout the study.
  • Post-menopausal women must meet one of these criteria: bilateral oophorectomy, age ≥60 years, age ≥50 years with ≥12 months amenorrhea and intact uterus without hormonal therapy, or age <60 years with ≥12 months amenorrhea and post-menopausal hormone levels.
  • Histological or cytological confirmation of adenocarcinoma of the breast.
  • Participants of childbearing potential must agree to use one highly effective contraceptive measure.
  • Documentation of ER-positive tumor irrespective of progesterone receptor status.

Main Exclusion Criteria:

  • A participant who has received 2 or more lines of CDK4/6 inhibitors in the advanced disease setting.
  • A participant who has received prior camizestrant or atirmociclib treatment in the advanced disease setting.
  • Patients previously treated with other next generation selective estrogen receptor degrader (SERDs) or other experimental ETs in the advanced disease setting.
  • Patients previously treated with other experimental cyclin-dependent kinase (CDK) inhibitors are not eligible.
  • Inability to swallow oral medications.
  • Any unresolved toxicities of Grade ≥ 2 from prior anti-cancer therapy (with the exception of alopecia).
  • Presence of life-threatening metastatic visceral disease.
  • Any evidence of severe or uncontrolled systemic diseases.
  • Contraindication to or known intolerance/hypersensitivity of/to camizestrant or atirmociclib.

Trial locations and contacts

6 sites in 2 countries. Contact the study team or a site near you to ask about taking part.

AstraZeneca Clinical Study Information Center contact

1-877-240-9479

information.center@astrazeneca.com

6 sites in 2 countries

United States3 sites, 3 recruiting

  • Research Site

    East Providence, Rhode Island, 02915

    Recruiting

  • Research Site

    Nashville, Tennessee, 37203

    Recruiting

  • Research Site

    St Louis, Missouri, 63108

    Recruiting

Other trials in United States

United Kingdom3 sites, 3 recruiting

  • Research Site

    Cambridge, CB2 0QQ

    Recruiting

  • Research Site

    London, EC1M6BQ

    Recruiting

  • Research Site

    Manchester, M20 4GJ

    Recruiting

Other trials in United Kingdom

About this study

Official title: A Phase IIa, Open-label Study to Evaluate the Safety, Pharmacokinetics and Preliminary Efficacy of Camizestrant in Combination With Atirmociclib in Participants With ER-positive, HER2-negative Advanced Breast Cancer (SERENA-1b)

A study to investigate camizestrant in combination with atirmociclib in participants with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer previously treated with a cyclin dependent kinase 4/6 (CDK4/6) inhibitor.

Read the detailed description

This is a Phase IIa, sequential assignment, non- randomized, open-label treatment study to determine the safety, tolerability, pharmacokinetics (PK) and preliminary anti-tumor activity of camizestrant in combination with atirmociclib.

The single-arm study includes:

  • Screening period
  • Atirmociclib single dose period
  • Doublet intervention period
  • Post-treatment follow-up period
Being tested
Camizestrant, Atirmociclib
Keywords
Estrogen receptor (ER)-positive, Human epidermal growth factor receptor 2 (HER2)-negative, Cyclin-Dependent Kinase (CDK) 4 inhibitors, Pharmacokinetics, Anti-tumor activity, Selective Estrogen Receptor Degrader (SERD), Safety, Tolerability

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • CamizestrantDrug

    Camizestrant will be administered orally.

  • AtirmociclibDrug

    Atirmociclib will be administered orally.

Study groups in NCT07427394
Study groupRoleWhat they receive
Camizestrant + AtirmociclibExperimentalParticipants will receive a single dose of atirmociclib on Day -1 followed by combination of camizestrant and atirmociclib from Day 1.
Receives: Drug: Camizestrant; Drug: Atirmociclib

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Number of participants with adverse events (AEs) and serious AEs

    To investigate the safety and tolerability of camizestrant in combination with atirmociclib.

    Measured: Up to Post-Treatment Follow up (Day 30 Post Dose)

Secondary outcomes (20)

  1. Maximum concentration observed (Cmax)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  2. Area under plasma concentration-time curve from time 0 to infinity (AUCinf)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  3. Area under plasma concentration-time curve from time 0 to last quantifiable concentration (AUClast)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  4. Time to reach maximum (peak) plasma concentration following drug administration (tmax)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  5. Terminal elimination rate constant (λz)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  6. Terminal elimination half-life (t½λz)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  7. Apparent total body clearance (CL/F)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  8. Apparent volume of distribution at steady state (Vss/F)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  9. Apparent volume of distribution based on the terminal phase (Vz/F)

    To characterize the PK profile and parameters of atirmociclib.

    Measured: At pre-defined intervals from Day -1 to Day 57

  10. Maximum concentration observed at steady state (Cssmax)

    To characterise the PK profile and parameters of atirmociclib and camizestrant after administration in combination with each other.

    Measured: At pre-defined intervals from Day -1 to Day 57

  11. Area under the curve from 0 to the end of dosing interval (AUC0-tau)

    To characterise the PK profile and parameters of atirmociclib and camizestrant after administration in combination with each other.

    Measured: At pre-defined intervals from Day -1 to Day 57

  12. Area under the curve from 0 to the end of dosing interval at steady state (AUCss0-tau)

    To characterise the PK profile and parameters of atirmociclib and camizestrant after administration in combination with each other.

    Measured: At pre-defined intervals from Day -1 to Day 57

  13. Time to reach maximum plasma concentration at steady state (tssmax)

    To characterise the PK profile and parameters of atirmociclib and camizestrant after administration in combination with each other.

    Measured: At pre-defined intervals from Day -1 to Day 57

  14. Objective Response Rate (ORR)

    To assess the preliminary anti-tumor activity and efficacy of camizestrant in combination with atirmociclib.

    Measured: Up to 2 years

  15. Duration of Response (DOR)

    To assess the preliminary anti-tumor activity and efficacy of camizestrant in combination with atirmociclib.

    Measured: Up to 2 years

  16. Clinical Benefit Rate at 24 Weeks (CBR24)

    To assess the preliminary anti-tumor activity and efficacy of camizestrant in combination with atirmociclib.

    Measured: At 24 weeks

  17. Percentage change in tumor size

    To assess the preliminary anti-tumor activity and efficacy of camizestrant in combination with atirmociclib.

    Measured: Up to 2 years

  18. Progression Free Survival (PFS)

    To assess the preliminary anti-tumor activity and efficacy of camizestrant in combination with atirmociclib.

    Measured: Up to 2 years

  19. Progression-free survival landmark 6 months (PFSLM6m)

    To assess the preliminary anti-tumor activity and efficacy of camizestrant in combination with atirmociclib.

    Measured: At 6 months

  20. Progression-free survival landmark 12 months (PFSLM12m)

    To assess the preliminary anti-tumor activity and efficacy of camizestrant in combination with atirmociclib.

    Measured: At 12 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted23 Feb 2026
  2. Study start6 May 2026
  3. Primary completion28 Dec 2027 (estimated)
  4. Study completion28 Dec 2027 (estimated)

Resources

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
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
24 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07427394
Sponsor's protocol ID
D853CC00001
Acronym
SERENA-1b
Status last verified
Sep 2026
First submitted
16 Feb 2026
Last updated
29 Sep 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure. Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Camizestrant and Atirmociclib in people with Advanced Breast Cancer, run by AstraZeneca at 6 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?

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: looking for participants now, as of the sponsor's last update on 29 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 6 sites in United States, United Kingdom. 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?

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?

Contact AstraZeneca Clinical Study Information Center (1-877-240-9479, information.center@astrazeneca.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Number of participants with adverse events (AEs) and serious AEs (time frame: Up to Post-Treatment Follow up (Day 30 Post Dose)). 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 NCT07427394.

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 29 Sep 2026.

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