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AstraZeneca (AZN) sees FDA delay but EMA backs camizestrant combo

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6-K

Rhea-AI Filing Summary

AstraZeneca reports that the US FDA has extended the Prescription Drug User Fee Act (PDUFA) decision date for the New Drug Application for camizestrant combined with a CDK4/6 inhibitor as 1st-line treatment for HR-positive, HER2-negative advanced breast cancer with emergent ESR1 mutations, to review additional requested data from the Phase III SERENA-6 trial.

The company has submitted new analyses, including ctDNA clearance data linked to longer-term efficacy that will be presented at ASCO 2026. In contrast to the extended US timeline, the European Medicines Agency’s human medicines committee has issued a positive opinion recommending approval, and camizestrant is already approved in this setting in the UAE and Saudi Arabia, with further regulatory reviews ongoing in Japan and other countries.

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Insights

FDA decision on camizestrant is delayed for more data, while Europe moves toward approval.

The FDA’s extension of the PDUFA date for camizestrant in 1st-line HR-positive, HER2-negative advanced breast cancer reflects a need to assess additional SERENA-6 data, including ctDNA clearance tied to longer-term outcomes. This follows an advisory committee that did not reach a majority in favor of benefit.

At the same time, Europe is moving ahead: the EMA’s committee has adopted a positive opinion recommending approval, and the drug is already approved in the UAE and Saudi Arabia, with filings under review in Japan and other markets. Overall direction is constructive, but US timing now depends on the FDA’s review of the supplemental analyses.

Global breast cancer incidence 2022 More than 2,000,000 cases Worldwide diagnoses in 2022
Global breast cancer deaths 2022 More than 665,000 deaths Worldwide breast cancer mortality in 2022
US annual breast cancer cases More than 300,000 cases New US diagnoses per year
US annual breast cancer deaths More than 42,000 deaths US breast cancer mortality per year
HR-positive, HER2-negative share 70% of tumors Proportion of breast cancers that are HR-positive, HER2-negative
SERENA-6 enrollment 315 patients Adults with HR-positive, HER2-negative advanced breast cancer
PDUFA date regulatory
"it will extend the Prescription Drug User Fee Act (PDUFA) date to review additional data"
PDUFA date is the deadline the U.S. Food and Drug Administration sets to complete its review of a drug or biologic application and decide whether to approve it. Investors watch it like a court verdict date: the decision can unlock sales and growth if approved or sharply reduce expected value if denied, so markets often move significantly as the date approaches or when the outcome is announced.
New Drug Application regulatory
"to support the New Drug Application (NDA) for camizestrant in combination with a cyclin-dependent kinase"
A new drug application is a formal request submitted to government regulators seeking approval to market a new medicine. It is like a detailed proposal that shows the drug has been tested for safety and effectiveness. For investors, receiving approval signals that the drug may soon become available for sale, potentially leading to revenue growth and impacting the company's value.
Breakthrough Therapy Designation regulatory
"The FDA granted Breakthrough Therapy Designation for the camizestrant combination in this setting"
A breakthrough therapy designation is a regulatory fast-track given to a drug or treatment that shows early signs of providing a major improvement over existing options for a serious condition. Think of it as a VIP lane that can speed up development and more intensive guidance from regulators, which matters to investors because it can shorten time to market, reduce development risk and potentially increase a company’s value — though it does not guarantee approval.
circulating tumour DNA (ctDNA) medical
"after detection of an ESR1 mutation in circulating tumour DNA (ctDNA) prior to radiographic progression"
selective estrogen receptor degrader (SERD) medical
"Camizestrant is an investigational, potent, next-generation oral selective estrogen receptor degrader (SERD)"
Phase III trial medical
"The NDA is based on positive results from the pivotal SERENA-6 Phase III trial"
A phase III trial is a large, late-stage clinical study that tests whether a new drug or medical treatment works and is safe in a broad group of patients; think of it as the final road test before regulators decide if a product can be sold widely. Investors watch these trials closely because positive results often trigger regulatory approval and major increases in a company’s value, while failures can sharply reduce prospects and share price.
FORM 6-K
 
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
 
 
Report of Foreign Issuer
 
Pursuant to Rule 13a-16 or 15d-16 of
the Securities Exchange Act of 1934
 
For the month of May 2026 
 
Commission File Number: 001-11960
 
AstraZeneca PLC
 
1 Francis Crick Avenue
Cambridge Biomedical Campus
Cambridge CB2 0AA
United Kingdom
 
 
Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.
 
Form 20-F X Form 40-F __
 
Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):
 
Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ______
 
Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.
 
Yes __ No X
 
If “Yes” is marked, indicate below the file number assigned to the Registrant in connection with Rule 12g3-2(b): 82-_____________
 
 
 
AstraZeneca PLC
 
INDEX TO EXHIBITS
 
 
1.
US FDA decision date on camizestrant extended
 
 
27 May 2026
 
US FDA decision date extended for SERENA-6 filing of camizestrant
to enable review of additional data
 
The US Food and Drug Administration (FDA) has informed AstraZeneca that it will extend the Prescription Drug User Fee Act (PDUFA) date to review additional data requested to support the New Drug Application (NDA) for camizestrant in combination with a cyclin-dependent kinase (CDK) 4/6 inhibitor (palbociclib, ribociclib or abemaciclib) for the 1st-line treatment of patients with hormone receptor (HR)-positive, HER2-negative advanced breast cancer whose tumours have an emergent ESR1 mutation.
 
The NDA is based on positive results from the pivotal SERENA-6 Phase III trial presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting and simultaneously published in The New England Journal of Medicine.1 The FDA granted Breakthrough Therapy Designation for the camizestrant combination in this setting in May 2025.
 
In April 2026, the FDA's Oncologic Drugs Advisory Committee did not reach a majority vote in favour of the benefit of switching to camizestrant in combination with a CDK4/6 inhibitor after detection of an ESR1 mutation in circulating tumour DNA (ctDNA) prior to radiographic progression, based on the SERENA-6 Phase III trial. Subsequently, the Company has provided additional analyses requested by the FDA in support of the application, including ctDNA clearance data linked to longer-term efficacy outcomes that will be presented on 02 June at ASCO 2026.
 
Susan Galbraith, Executive Vice President, Oncology Haematology R&D, AstraZeneca, said: "We are committed to continuously advancing the clinical landscape in oncology in pursuit of improving outcomes for patients. The SERENA-6 treatment strategy epitomises this approach by monitoring patients for the emergence of ESR1 mutations in ctDNA and testing if a switch of endocrine backbone therapy at this point improves outcomes. We look forward to continuing the dialogue with the FDA in order to bring the benefits of camizestrant with this innovative treatment strategy to eligible patients in the US as quickly as possible."
 
On 22 May, the European Medicines Agency's Committee for Medicinal Products for Human Use adopted a positive opinion recommending approval of the camizestrant combination in this setting based on the results of the SERENA-6 Phase III trial.
 
Camizestrant is approved in the United Arab Emirates and Saudi Arabia in this setting. Regulatory applications are also currently under review in Japan and several other countries based on the SERENA-6 Phase III trial.
 
Notes
 
HR-positive breast cancer
Breast cancer is the second most common cancer and one of the leading causes of cancer-related deaths worldwide.More than two million patients were diagnosed with breast cancer in 2022, with more than 665,000 deaths globally.2 In the US, breast cancer is the most common cancer in women, with more than 300,000 new cases of the disease diagnosed annually, and more than 42,000 deaths.3 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.4 
 
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.4 Estrogen receptor (ERs) often drive the growth of HR-positive breast cancer cells.5
 
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.6-8 In the US, approximately 37,000 patients with HR-positive metastatic breast cancer are treated with these therapies in the 1st-line setting.6-8 However, resistance to these therapies develops in many patients.8 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.4,8
 
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.9,10 Approximately 30% of patients with endocrine sensitive HR-positive disease develop ESR1 mutations during 1st-line treatment before disease progression.6
 
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 expanding 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 (capivasertib), 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
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 and follow the Company on Social Media @AstraZeneca.
 
Contacts
For details on how to contact the Investor Relations Team, please click here. For Media contacts, click here.
 
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.   American Cancer Society. Key Statistics for Breast Cancer. Available at: https://www.cancer.org/cancer/types/breast-cancer/about/how-common-is-breast-cancer.html. Accessed May 2026.
4.   National Cancer Institute. Cancer Stat facts: Female breast cancer subtypes. Available at: https://seer.cancer.gov/statfacts/html/breast-subtypes.html. Accessed May 2026.
5.   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.
6.   Cerner CancerMPact database. Accessed May 2026.
7.   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.
8.   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.
9.   Brett O, et al. ESR1 mutation as an emerging clinical biomarker in metastatic hormone receptor-positive breast cancer. Breast Cancer Res. 2021; 23:85.
10.  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​
 
 
SIGNATURES
 
Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
 
 
AstraZeneca PLC
 
 
Date: 27 May 2026
 
 
By: /s/ Matthew Bowden
 
Name: Matthew Bowden
 
Title: Company Secretary

FAQ

What did AstraZeneca (AZN) announce about the FDA review of camizestrant?

AstraZeneca announced that the US FDA extended the PDUFA decision date for camizestrant’s New Drug Application to review additional requested data from the SERENA-6 Phase III trial in HR-positive, HER2-negative advanced breast cancer with emergent ESR1 mutations.

What is the SERENA-6 trial referenced by AstraZeneca (AZN)?

SERENA-6 is a Phase III, double-blind, randomized trial of camizestrant plus a CDK4/6 inhibitor versus an aromatase inhibitor plus a CDK4/6 inhibitor in 315 adults with HR-positive, HER2-negative advanced breast cancer whose tumors developed emergent ESR1 mutations during 1st-line therapy.

How has the EMA progressed camizestrant for AstraZeneca (AZN)?

The European Medicines Agency’s Committee for Medicinal Products for Human Use adopted a positive opinion recommending approval of camizestrant in combination with a CDK4/6 inhibitor for HR-positive, HER2-negative advanced breast cancer with emergent ESR1 mutations, based on SERENA-6 results.

In which countries is camizestrant already approved, according to AstraZeneca (AZN)?

Camizestrant is approved in the United Arab Emirates and Saudi Arabia for 1st-line treatment of HR-positive, HER2-negative advanced breast cancer with emergent ESR1 mutations, using the SERENA-6 Phase III trial as the key evidence base for these regulatory decisions.

What additional data is AstraZeneca (AZN) providing for camizestrant’s FDA review?

AstraZeneca is providing extra analyses requested by the FDA, including circulating tumor DNA (ctDNA) clearance data linked to longer-term efficacy outcomes from SERENA-6, with these results scheduled for presentation at the ASCO 2026 meeting before being fully considered in the regulatory review.

How common is HR-positive, HER2-negative breast cancer targeted by camizestrant?

HR-positive, HER2-negative breast cancer represents about 70% of breast tumors, and globally around 200,000 patients are treated with 1st-line endocrine therapy plus CDK4/6 inhibitors annually, highlighting a large population that could be affected by resistance and potential new treatment options like camizestrant.