#USA #San Antonio #MEDSIR #HER2+ Breast Cancer #ctDNA

The Breakthrough of Circulating Tumor DNA in Breast Cancer Research

The PHERGuide study has made significant strides in the field of oncology by effectively demonstrating how circulating tumor DNA (ctDNA) can serve as a pivotal tool for the early detection and ongoing monitoring of localized HER2+ breast cancer. This study, unveiled during the 2025 San Antonio Breast Cancer Symposium (SABCS), underscores the potential of ctDNA in revolutionizing patient care through more personalized treatment options.

Groundbreaking Findings

Conducted by MEDSIR, a prominent player in oncology research, the results from the PHERGuide study have opened new avenues in non-invasive cancer monitoring. The research involved analyzing over 250 patient samples to investigate the correlation between the presence of ctDNA and disease stage. The findings show that higher levels of ctDNA in the bloodstream align directly with advanced stages of the disease.

Furthermore, the study revealed that treating patients resulted in a remarkable reduction of ctDNA. After just two cycles of therapy, about 75% of the participants experienced the elimination of ctDNA, with even more impressive results preceding surgery, where levels minimized by 83%. Those patients who successfully cleared ctDNA exhibited a significantly higher chance of positive treatment response.

Dr. Antonio Llombart-Cussac, the study's principal investigator and Head of Oncology at Hospital Arnau de Villanova in Valencia, Spain, expressed excitement about these implications. He notes, “This finding lays the groundwork for employing liquid biopsies as non-invasive tools to assess a patient's disease status. Real-time insights into disease status will empower us to make more tailored and effective treatment decisions for patients.”

Impact on Prognosis

Patients who either presented no ctDNA initially or cleared it prior to surgery enjoyed a substantially more favorable prognosis, with their likelihood of developing invasive disease reduced by four to five times over a three-year follow-up period. Such outcomes provide compelling evidence for the integration of ctDNA monitoring in clinical practices.

Looking Ahead: PONTIAC and CEBBRAH Studies

In addition to the PHERGuide findings, MEDSIR also showcased the design of the PONTIAC study at SABCS 2025. This Phase II trial aims to assess the efficacy and safety of trastuzumab deruxtecan (T-DXd) as a first-line treatment for patients with HR+/HER2-low/ultralow breast cancer. This specific type of breast cancer presents decreased sensitivity to conventional hormonal therapies, necessitating the evaluation of innovative treatment strategies.

T-DXd represents a new generation of treatment combining trastuzumab, an antibody that targets HER2 protein, with deruxtecan, a potent chemotherapy agent. This therapeutic strategy is anticipated to maximize anti-tumor effects while minimizing adverse side effects, hence contributing to improved patient treatment experiences.

Dr. Javier Cortés, leading investigator of the PONTIAC study, has emphasized the promise this study holds for patients with hard-to-treat subtypes of breast cancer. The ongoing quest for effective and less damaging alternatives could radically alter treatment paradigms for this population.

Contributions to Scientific Discourse

MEDSIR's participation in the SABCS extended beyond the PHERGuide study. They also presented insights from the CEBBRAH study, which delved into the presence of ctDNA in both plasma and cerebrospinal fluid among individuals with HER2+ breast cancer complicated by leptomeningeal disease receiving T-DXd. Data indicated that patients showing reduced ctDNA in the cerebrospinal fluid after treatment showed significantly better disease control.

A Paradigm Shift in Oncology

The congress also featured discussions on new trends in oncological research, led by top experts from both national and international spheres. The roundtable sessions spotlighted the relevance of utilizing technologies like ctDNA for managing HER2+ breast tumors, accentuating precision oncology's growing impact on enhancing patient life quality.

MEDSIR's commitment to advancing oncological research was further evident through their various presentations at SABCS 2025, including additional studies like ADELA and TUXEDO-3, which evaluated new treatment strategies in differing contexts of breast cancer.

Conclusion

The developments from the PHERGuide study and concurrent research underscore an exciting era in breast cancer treatment and monitoring. By integrating ctDNA as a standard in clinical practice, healthcare professionals could enhance patient outcomes through more personalized, informed treatment pathways. As research continues to evolve, the potential of liquid biopsy in oncology promises to redefine patient care and the future landscape of cancer treatment.