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Taking people in United KingdomPhase 2

Camizestrant plus atirmociclib for advanced ER-positive, HER2-negative breast cancer

Tests camizestrant with atirmociclib in women whose advanced breast cancer was treated before.

Key facts

Who runs it
AstraZeneca
Where
Cambridge, London, and Manchester, United KingdomSee the 3 sitesAlso in 1 other country, 3 sites
Trial code
Registry title
Study to Evaluate the Safety and Tolerability of Camizestrant in Combination With Atirmociclib in Women With Advanced Breast Cancer
Status
Recruiting
Phase
Phase 2
People taking part
24 people, planned
Started
6 May 2026
Expected to end
28 Dec 2027
Type of study
Interventional
Treatments tested
  • Camizestrant
  • Atirmociclib
Record updated
29 September 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for women with advanced breast cancer that is ER-positive and HER2-negative. The cancer must have progressed after earlier treatment, including a CDK4/6 inhibitor.

Age
18 years or older
Sex
Women only
Disease stage
Advanced adenocarcinoma of the breast, metastatic or locoregionally recurrent, with signs of progression on or after the last treatment. At least one lesion that can be assessed on scans or by clinical examination. Performance status (ECOG/WHO) 0 to 1 and expected life span of at least 12 weeks.
Earlier treatment
Must have had adequate earlier treatment for the tumor type and stage, and a CDK4/6 inhibitor. Cannot have had 2 or more lines of CDK4/6 inhibitors, camizestrant, atirmociclib, other next generation SERDs, other experimental hormone therapies or other experimental CDK inhibitors for advanced disease. Women before menopause must start GnRH agonist therapy at least 4 weeks before study treatment.
Biomarker or test result
ER-positive tumor, whatever the progesterone receptor status. HER2-negative.

Main reasons for not taking part

  • 2 or more lines of CDK4/6 inhibitors for advanced disease
  • Earlier treatment with camizestrant, atirmociclib, other next generation SERDs or experimental CDK inhibitors
  • Cannot swallow oral medicines
  • Unresolved side effects of Grade 2 or higher from earlier cancer treatment (except hair loss)
  • Life-threatening metastatic disease of the internal organs, or severe or uncontrolled systemic disease

The registry criteria, word for word

Show all 18 criteriaShow less

Other criteria

  • 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

Where in United Kingdom

Also in 1 other country, 3 sites

  • CambridgeHospital not named in the registryTaking people
  • LondonHospital not named in the registryTaking people
  • ManchesterHospital not named in the registryTaking people

About the trial

What the trial wants to find out

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.

The group in the trial

  • Camizestrant + AtirmociclibTreatment being tested

    Participants will receive a single dose of atirmociclib on Day -1 followed by combination of camizestrant and atirmociclib from Day 1.

    Treatment: Camizestrant and Atirmociclib

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov.
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)
Plain-language title
Camizestrant plus atirmociclib for advanced ER-positive, HER2-negative breast cancerGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 12 November 2026.
Record updated
29 September 2026