Breast cancer research is becoming more precise, and clinical trials are becoming more demanding. As new therapies target increasingly specific patient populations, sponsors face a growing challenge: identifying the right patients, selecting the right sites and designing studies that can keep pace with advances in treatment.
Breast Cancer Awareness Month offers an opportunity to look at these developments and what they mean for clinical research.
According to the World Health Organization (WHO), an estimated 2.4 million women were diagnosed with breast cancer worldwide in 2024, with approximately 694,000 deaths. Although less common, men can also develop breast cancer. Despite considerable progress, access to early diagnosis, molecular testing and effective treatment continues to vary significantly between regions.
For global clinical development programmes, these differences have practical implications for patient recruitment, site selection and study execution.
Advances Shaping Breast Cancer Clinical Development
Breast cancer treatment is increasingly guided by tumour biology, molecular characteristics and individual patient factors. Several developments are changing both therapeutic approaches and the way clinical trials are designed.
Antibody-drug conjugates (ADCs) and HER2 classification
ADCs are expanding treatment options across different breast cancer subtypes. The recognition of HER2-low and HER2-ultralow disease has also broadened treatment eligibility for certain patient populations.
For clinical trials, this places greater importance on accurate biomarker assessment, standardised testing and the ability to identify patients who meet increasingly specific eligibility criteria.
Next-generation endocrine therapies
New oral endocrine agents, combinations with CDK4/6 inhibitors and biomarker-selected treatment strategies are creating additional options for patients with hormone receptor-positive breast cancer.
Research is also examining how resistance-associated mutations can guide treatment selection and sequencing. These developments bring new opportunities but require careful consideration of previous treatments, molecular testing and evolving standards of care.
Circulating tumour DNA (ctDNA)
Liquid biopsy continues to attract significant interest in oncology research. In breast cancer, ctDNA is being investigated for detecting molecular residual disease, monitoring treatment response and identifying emerging resistance.
While certain mutation-based applications already have a role in treatment selection, other uses, particularly routine recurrence monitoring, remain investigational. Clinical studies will be important in establishing where ctDNA-guided decisions improve patient outcomes.
Treatment de-escalation
Alongside the development of new therapies, researchers are investigating whether treatment intensity can be safely reduced for selected patients.
The objective is to maintain clinical effectiveness while limiting unnecessary toxicity and long-term treatment burden. This requires carefully defined patient populations and appropriate endpoints to demonstrate that reducing treatment does not compromise outcomes.
What These Developments Mean for Clinical Trials
Greater treatment precision introduces new challenges for clinical development.
Biomarker-driven studies often involve smaller and more narrowly defined patient populations. Although breast cancer remains highly prevalent, identifying patients with the required molecular characteristics, treatment history and disease stage can be considerably more difficult.
Recruitment therefore depends on more than patient numbers. Sponsors need to understand whether participating sites have access to the necessary diagnostic tests, how quickly results can be obtained and whether suitable patients can be identified through existing referral pathways.
The changing standard of care adds another consideration. New treatment approvals and evolving clinical guidelines can affect comparator selection, eligibility criteria and recruitment assumptions, particularly in studies running across multiple countries.
Patient-reported outcomes (PROs) are another important part of this discussion.
Traditional endpoints such as tumour response, progression-free survival and overall survival remain central to oncology trials. However, they do not fully capture how treatment affects patients in their daily lives.
PROs provide additional insight into symptoms, tolerability, functional status and quality of life. This is particularly relevant when patients receive treatment over extended periods or when therapies demonstrate similar efficacy but different safety and tolerability profiles.
Research has identified inconsistencies in how PROs are planned, analysed and reported in breast cancer trials. More systematic integration can improve the quality of evidence generated and provide a more complete understanding of treatment benefit.
Planning for Clinical Trial Complexity
Scientific innovation is only one part of successful clinical development. Translating new treatment approaches into well-executed studies requires early planning and a clear understanding of operational realities.
For biomarker-driven breast cancer trials, feasibility assessments must go beyond traditional site capabilities and historical recruitment figures.
Sponsors need to consider several practical questions:
These considerations are particularly important in global studies, where access to diagnostics, treatment pathways and healthcare infrastructure can differ considerably.
In our experience, two common execution risks are underestimating complexity during the planning stage and developing country strategies based on assumptions rather than realistic enrolment potential.
Addressing these risks requires cross-functional feasibility assessments, analysis of historical site performance and flexibility in country and site selection.
Early coordination between clinical operations, regulatory teams, medical experts, laboratories and clinical supply specialists can help identify potential obstacles before they affect study timelines.
Supporting Breast Cancer Clinical Trials at SanaClis
SanaClis has supported well over 200 oncology studies, including over 40 in breast cancer indications, bringing experience across different oncology development programmes.
As a full-service CRO with an integrated clinical supply chain, we understand the importance of aligning study design, patient recruitment, site capabilities and investigational product supply from the outset.
Our teams bring together expertise in project management, clinical operations, regulatory affairs and study start-up, monitoring, data management, biostatistics, medical and safety oversight, and clinical supply chain services.
For breast cancer studies involving complex eligibility requirements or biomarker-driven patient selection, this integrated approach supports more informed feasibility assessments, coordinated study execution and greater continuity throughout development.
We also recognise that no two clinical development programmes face exactly the same challenges. Study strategies need to reflect the target population, treatment approach, geographical footprint and operational requirements rather than relying on a standard model.
Breast cancer research has made significant progress, but turning scientific advances into effective treatments depends on clinical trials that are both scientifically rigorous and operationally realistic.
Identifying the right patients, understanding local treatment pathways and anticipating challenges early can make a meaningful difference to how successfully a study is delivered.
Planning a breast cancer clinical trial?
Connect with the SanaClis oncology team to discuss feasibility, site strategy and clinical supply planning for your development program.