Breast Cancer Clinical Trials in the UK (2026)
Breast cancer is the most common cancer in the UK, with around 55,000 people diagnosed each year. It is also one of the most active areas of clinical research globally, with hundreds of trials running across the UK at any time. This guide explains the types of breast cancer trials currently recruiting, who can take part, and how to find studies that match your situation.
Types of Breast Cancer Clinical Trials
Breast cancer trials span every stage of the disease and nearly every treatment approach. The main categories include:
Testing drugs that target specific features of cancer cells, such as HER2+ therapies (trastuzumab deruxtecan, tucatinib), CDK4/6 inhibitors, PI3K inhibitors, and AKT inhibitors. Many target specific biomarkers like BRCA mutations or PIK3CA.
Particularly active in triple-negative breast cancer (TNBC). Trials combine checkpoint inhibitors (pembrolizumab, atezolizumab) with chemotherapy or test immunotherapy in earlier disease stages.
One of the fastest-growing areas. ADCs like trastuzumab deruxtecan (Enhertu) and sacituzumab govitecan are being tested across multiple breast cancer subtypes and lines of therapy.
For HR+/HER2- breast cancer — the most common subtype. Trials test new oral SERDs (elacestrant, camizestrant), PROTAC degraders, and combination approaches to overcome resistance.
Trial Phases in Breast Cancer
Breast cancer trials range from early-phase dose-finding studies to large Phase 3 randomised trials comparing new treatments against the current standard of care:
- Phase 1 — Testing safety and dosing of entirely new drugs, often for patients who have exhausted standard options
- Phase 2 — Assessing how well a treatment works in a specific subtype (e.g. TNBC with PD-L1 expression)
- Phase 3 — Large randomised trials that may change standard practice. Many UK breast cancer Phase 3 trials are run through the NHS and NCRN network
Biomarkers and Eligibility
Many breast cancer trials require specific biomarker test results to determine eligibility. The most common include:
- HER2 status — Positive, negative, or low expression (HER2-low is an emerging trial category)
- Hormone receptor status — ER+ and/or PR+ vs. triple-negative
- BRCA1/BRCA2 mutations — Required for PARP inhibitor trials
- PIK3CA mutations — Required for PI3K inhibitor trials (alpelisib)
- PD-L1 expression — May be required for immunotherapy trials in TNBC
- ESR1 mutations — Emerging biomarker for oral SERD trials
Tip: You do not need to know your biomarker status to search for trials. Our Smart Matcher lets you skip biomarkers you're unsure about and still find relevant studies.
Who Can Take Part?
Eligibility varies by trial, but common requirements include:
- A confirmed breast cancer diagnosis with specific subtype and stage
- Measurable disease (for trials assessing tumour response)
- Adequate organ function (blood tests, liver and kidney function)
- Performance status indicating you can carry out daily activities
- No recent participation in another clinical trial (typically 28-day washout)
Some trials accept patients who have had prior treatments; others are for treatment-naive patients. The number and type of prior therapies is one of the most important eligibility criteria.
UK Trial Locations
Breast cancer trials run across the UK, with major research centres in:
- London — The Royal Marsden, Guy's Hospital, UCLH
- Manchester — The Christie NHS Foundation Trust
- Cambridge — Addenbrooke's Hospital
- Edinburgh — Edinburgh Cancer Centre
- Glasgow — Beatson West of Scotland Cancer Centre
- Birmingham — Queen Elizabeth Hospital
- Leeds — St James's University Hospital
- Southampton — University Hospital Southampton
Most NHS cancer centres participate in national trials through the National Cancer Research Institute (NCRI) network. Your oncologist can refer you to the nearest participating site.
What to Expect
If you join a breast cancer clinical trial:
- You will receive the trial treatment and standard monitoring at no cost
- Your care team will include both your regular oncologist and the trial research team
- You may need extra hospital visits for blood tests, scans, and assessments
- You can leave the trial at any time without it affecting your standard care
- Your data is protected under GDPR and the trial's ethics approval
How to Find Breast Cancer Trials
The fastest way to find breast cancer trials that match your specific situation is to use our matching tool. It asks about your subtype, biomarkers, treatment history, and location to surface the most relevant studies.
Find Your Matching Trials
Answer a few questions about your breast cancer diagnosis and we'll show you the most relevant actively recruiting trials near you.
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