REG - AstraZeneca PLC - Camizestrant recommended for breast cancer in EU

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RNS Number : 6560F  AstraZeneca PLC  26 May 2026

26 May 2026

 

Camizestrant in combination with a CDK4/6 inhibitor recommended for approval
in the EU by CHMP for 1st-line advanced ER-positive breast cancer

Recommendation based on SERENA-6 Phase III trial results which showed
combination reduced the risk of disease progression or death by 56% in
patients with an emergent ESR1 tumour mutation

If approved, camizestrant has the potential to reshape 1st-line treatment for
patients in Europe with this type of advanced breast cancer

AstraZeneca's camizestrant in combination with a cyclin-dependent kinase (CDK)
4/6 inhibitor (palbociclib, ribociclib or abemaciclib) has been recommended
for approval in the European Union (EU) for the treatment of adult patients
with estrogen receptor (ER)-positive, HER2-negative locally advanced or
metastatic breast cancer upon detection of ESR1 mutation and without disease
progression during 1st-line endocrine therapy in combination with a CDK4/6
inhibitor.

The Committee for Medicinal Products for Human Use (CHMP) of the European
Medicines Agency (EMA) based its positive opinion on the results from the
pivotal SERENA-6 Phase III trial, which were presented at the 2025 American
Society of Clinical Oncology (ASCO) Annual Meeting and simultaneously
published in The New England Journal of Medicine (https://www.nejm.org/) .(1)

In a planned interim analysis, the camizestrant combination reduced the risk
of disease progression or death by 56% versus standard-of-care treatment with
an aromatase inhibitor (AI) (anastrozole or letrozole) in combination with a
CDK4/6 inhibitor (based on a hazard ratio  HR  of 0.44; 95% confidence
interval  CI  0.31-0.60; p<0.00001; median progression-free survival (PFS)
16.0 versus 9.2 months). Data for the key secondary endpoints of time to
second disease progression (PFS2) and overall survival (OS) were immature at
the time of the interim analysis, however a subsequent pre-planned analysis
demonstrated a statistically significant and clinically meaningful PFS2
benefit of 25.7 months versus 19.1 months in favour of the camizestrant
combination (HR: 0.63; 95% CI: 0.46-0.86; p = 0.00373) and OS continued to
mature in favour of the camizestrant combination (HR: 0.87; 95% CI:
0.57-1.30). The trial will continue to assess OS as a key secondary
endpoint.

François-Clément Bidard, MD, PhD, Professor of Medical Oncology at Institut
Curie & Versailles University (Paris/Saclay), France, and co-principal
investigator for the SERENA-6 trial, said: "This recommendation represents an
important step forward for patients with advanced breast cancer in Europe and
a milestone in the adoption of new treatment strategies. There is a need for
new treatments that delay disease progression in the 1st-line setting, after
which the cancer becomes harder to treat, and a patient's quality of life may
decline. Through prompt intervention with the camizestrant combination to
treat emergence of resistance before it causes disease progression and
deterioration of quality of life, we are able to extend the benefit of
1st-line treatment and optimise outcomes."

 

Susan Galbraith, Executive Vice President, Oncology Haematology R&D,
AstraZeneca, said: "This decision from the EU's CHMP is a vote of confidence
in SERENA-6, the first pivotal trial to demonstrate the clinical value of
monitoring circulating tumour DNA to detect emerging endocrine resistance and
guide a change of therapeutic strategy in the 1st-line setting. If approved,
camizestrant would be the first and only next-generation oral SERD and
complete ER antagonist for use in combination with widely approved CDK4/6
inhibitors in this setting, reinforcing the practice-changing potential of
this approach to advance patient outcomes and evolve the clinical landscape."

 

The safety profile of camizestrant in combination with palbociclib,
ribociclib or abemaciclib in the SERENA-6 trial was consistent with the known
safety profile of each medicine. No new safety concerns were identified and
discontinuations were very low and similar in both arms.(1)

SERENA-6 is the first global, double-blind, registrational Phase III trial to
use a circulating tumour DNA (ctDNA)-guided approach to detect the emergence
of endocrine resistance and inform a switch in therapy before disease
progression. The innovative trial design used ctDNA monitoring via a blood
test at the time of routine tumour scans every two to three months to identify
patients for early signs of endocrine resistance via the emergence of ESR1
mutations. Following detection of an ESR1 mutation without disease
progression, the endocrine therapy of patients was switched to camizestrant
from ongoing treatment with an AI, while continuing combination with the same
CDK4/6 inhibitor.

The camizestrant combination is approved in the United Arab Emirates and Saudi
Arabia in hormone receptor (HR)-positive, HER2-negative advanced breast cancer
patients whose tumours have an emergent ESR1 mutation based on the results of
the SERENA-6 Phase III trial.

 

Regulatory applications for camizestrant in this setting are currently under
review in the US, Japan and several other countries.

 

Notes

 

HR-positive breast cancer

Breast cancer is the second most common cancer and one of the leading causes
of cancer-related deaths worldwide.(2 )More than two million patients were
diagnosed with breast cancer in 2022, with more than 665,000 deaths
globally.(2) While survival rates are high for those diagnosed with early
breast cancer, only about 30% of patients diagnosed with or who progress to
metastatic disease are expected to live five years following diagnosis.(3)

 

HR-positive breast cancer, characterised by the expression of estrogen or
progesterone receptors, or both, is the most common subtype of breast cancer
with 70% of tumours considered HR-positive and HER2-negative.(3) More than 97%
of HR-positive breast cancer tumours are ER-positive.(4,5) ERs often drive the
growth of HR-positive breast cancer cells.(6)

 

Globally, approximately 200,000 patients with HR-positive breast cancer are
treated with a medicine in the 1st-line setting; most frequently with
endocrine therapies that target ER-driven disease, which are often paired with
CDK4/6 inhibitors.(7-9) However, resistance to these therapies develops in
many patients.(9) Once this occurs, treatment options are limited and survival
rates are low with approximately 36% of patients anticipated to live beyond
five years after diagnosis.(3,9)

 

Mutations in the ESR1 gene are a key driver of endocrine resistance and are
associated with poor outcomes, emerging during treatment of the disease and
becoming more prevalent as the disease progresses.(10,11) Approximately 30% of
patients with endocrine sensitive HR-positive disease develop ESR1 mutations
during 1st-line treatment before disease progression.(7)

 

The optimisation of endocrine therapy and overcoming resistance to enable
patients to continue benefiting from these treatments, as well
as identifying new therapies for those who are less likely to benefit, are
active areas of focus for breast cancer research.

 

SERENA-6

SERENA-6 is a Phase III, double-blind, randomised trial evaluating the
efficacy and safety of camizestrant in combination with a CDK4/6 inhibitor
(palbociclib, ribociclib or abemaciclib) versus treatment with an AI
(anastrozole or letrozole) in combination with a CDK4/6 inhibitor
(palbociclib, ribociclib or abemaciclib) in patients with HR-positive,
HER2-negative advanced breast cancer (patients with either locally advanced
disease, or metastatic disease) whose tumours have an emergent ESR1 mutation.

 

The global trial enrolled 315 adult patients with histologically confirmed
HR-positive, HER2-negative advanced breast cancer, undergoing treatment with
an AI in combination with a CDK4/6 inhibitor as 1st-line treatment. The
primary endpoint of the SERENA-6 trial is PFS as assessed by investigator,
with secondary endpoints including OS, and PFS2 by investigator assessment.

 

Camizestrant

Camizestrant is an investigational, potent, next-generation oral selective
estrogen receptor degrader (SERD) and complete ER antagonist that is currently
in Phase III trials for the treatment of HR-positive breast cancer.

 

AstraZeneca's broad, robust and innovative clinical development programme,
including the SERENA-6, SERENA-4, CAMBRIA-1 and CAMBRIA-2 trials, is
evaluating the safety and efficacy of camizestrant when used as a monotherapy
or in combination with CDK4/6 inhibitors to address a number of areas of unmet
need in HR-positive, HER2-negative breast cancer.

 

Camizestrant has demonstrated anti-cancer activity across a range of
preclinical models, including those with ER-activating mutations. In the
SERENA-2 Phase II trial, camizestrant demonstrated a statistically significant
and clinically meaningful improvement in PFS versus Faslodex (fulvestrant) in
the overall trial population, including in patients with ESR1 tumour mutations
irrespective of prior treatment with CDK4/6 inhibitors in patients with
ER-positive locally advanced or metastatic breast cancer, previously treated
with endocrine therapy. The SERENA-1 Phase I trial demonstrated that
camizestrant is well tolerated and has a promising anti-tumour profile when
administered alone or in combination with palbociclib, ribociclib and
abemaciclib; three widely used CDK4/6 inhibitors.

 

AstraZeneca in breast cancer

Driven by a growing understanding of breast cancer biology, AstraZeneca is
challenging, and redefining, the current clinical paradigm for how breast
cancer is classified and treated to deliver even more effective treatments to
patients in need - with the bold ambition to one day eliminate breast cancer
as a cause of death.

 

AstraZeneca has a comprehensive portfolio of approved and promising compounds
in development that leverage different mechanisms of action to address the
biologically diverse breast cancer tumour environment.

 

With Enhertu (trastuzumab deruxtecan), a HER2-directed antibody drug conjugate
(ADC), AstraZeneca and Daiichi Sankyo are aiming to improve outcomes in
previously treated HER2-positive, HER2-low and HER2-ultralow metastatic breast
cancer, and are exploring its potential in earlier lines of treatment and in
new breast cancer settings.

 

In HR-positive breast cancer, AstraZeneca continues to improve outcomes with
foundational medicines Faslodex and Zoladex (goserelin) and aims to reshape
the HR-positive space with first-in-class AKT inhibitor, Truqap, the
TROP-2-directed ADC, Datroway (datopotamab deruxtecan) and next-generation
oral SERD and potential new medicine camizestrant.

 

PARP inhibitor Lynparza (olaparib) is a targeted treatment option that has
been studied in early and metastatic breast cancer patients with an inherited
BRCA mutation. AstraZeneca with MSD (Merck & Co., Inc. in the US and
Canada) continue to research Lynparza in these settings. AstraZeneca is also
exploring the potential of saruparib, a potent and selective inhibitor of
PARP1, in combination with camizestrant in BRCA-mutated, HR-positive,
HER2-negative advanced breast cancer.

 

To bring much-needed treatment options to patients with triple-negative breast
cancer, an aggressive form of breast cancer, AstraZeneca is collaborating with
Daiichi Sankyo to evaluate the potential of Datroway alone and in combination
with immunotherapy Imfinzi (durvalumab).

 

AstraZeneca in oncology

AstraZeneca is leading a revolution in oncology with the ambition to provide
cures for cancer in every form, following the science to understand cancer and
all its complexities to discover, develop and deliver life-changing medicines
to patients.

 

The Company's focus is on some of the most challenging cancers. It is through
persistent innovation that AstraZeneca has built one of the most diverse
portfolios and pipelines in the industry, with the potential to catalyse
changes in the practice of medicine and transform the patient experience.

 

AstraZeneca has the vision to redefine cancer care and, one day, eliminate
cancer as a cause of death.

 

AstraZeneca (https://www.astrazeneca.com/)

AstraZeneca (LSE/STO/NYSE: AZN) is a global, science-led biopharmaceutical
company that focuses on the discovery, development, and commercialisation of
prescription medicines in Oncology, Rare Disease, and BioPharmaceuticals,
including Cardiovascular, Renal & Metabolism, and Respiratory &
Immunology. Based in Cambridge, UK, AstraZeneca's innovative medicines are
sold in more than 125 countries and used by millions of patients worldwide.
Please visit astrazeneca.com (http://www.astrazeneca.com/) and follow the
Company on Social Media @AstraZeneca
(https://www.linkedin.com/company/astrazeneca) .

 

Contacts

For details on how to contact the Investor Relations Team, please click here
(https://www.astrazeneca.com/investor-relations.html#Contacts) . For Media
contacts, click here (https://www.astrazeneca.com/media-centre/contacts.html)
.

 

References

1.   Bidard FC, et al. First-Line Camizestrant for Emerging ESR1-Mutated
Advanced Breast Cancer. N Engl J Med 2025; DOI: 10.1056/NEJMoa2502929.

2.   Bray F, et al. Global cancer statistics 2022: GLOBOCAN estimates of
incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J
Clin. 2024; 1- 35. DOI:10.3322/caac.21834.

3.   National Cancer Institute. Cancer Stat facts: Female breast cancer
subtypes. Available at:
https://seer.cancer.gov/statfacts/html/breast-subtypes.html
(https://seer.cancer.gov/statfacts/html/breast-subtypes.html) . Accessed May
2026.

4.   Bae S, et al. Poor prognosis of single hormone receptor positive breast
cancer: similar outcome as triple-negative breast cancer. BMC Cancer. 2015;
15:138.

5.   Cserni G, et al. Estrogen Receptor Negative and Progesterone Receptor
Positive Breast Carcinomas-How Frequent are they? Pathol. Oncol. Res. 2011;
17:663-668.

6.   Scabia V, et al. Estrogen receptor positive breast cancers have patient
specific hormone sensitivities and rely on progesterone receptor. Nat Commun.
2022; 10.1038/s41467-022-30898-0.

7.   Cerner CancerMPact database. Accessed May 2026.

8.   Lin M, et al. Comparative Overall Survival of CDK4/6 Inhibitors Plus
Endocrine Therapy vs. Endocrine Therapy Alone for Hormone receptor-positive,
HER2-negative metastatic breast cancer. J Cancer. 2020; 10.7150/jca.48944.

9.   Lloyd M R, et al. Mechanisms of Resistance to CDK4/6 Blockade in
Advanced Hormone Receptor-positive, HER2-negative Breast Cancer and Emerging
Therapeutic Opportunities. Clin Cancer Res. 2022; 28(5):821-30.

10.  Brett O, et al. ESR1 mutation as an emerging clinical biomarker in
metastatic hormone receptor‑positive breast cancer. Breast Cancer Res. 2021;
23:85.

11.  Zundelevich A, et al. ESR1 mutations are frequent in newly diagnosed
metastatic and loco-regional recurrence of endocrine-treated breast cancer and
carry worse prognosis. Breast Cancer Res. 2020; 22:16.

 

Matthew Bowden

Company Secretary

AstraZeneca PLC

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