Breast cancer treatment has transformed dramatically over the past two decades. What was once a broad, often harsh approach, is now becoming increasingly precise and personalized. This evolution is largely thanks to a deeper understanding of tumor biology, paving the way for targeted therapies that offer remarkable efficacy with fewer side effects.
UCLA Health has consistently stood at the forefront of this revolution, with its researchers and clinicians leading groundbreaking advancements that redefine care for breast cancer patients worldwide. From the introduction of game-changing drugs to the development of sophisticated antibody-drug conjugates, UCLA Health continues to shape the future of oncology.
Table of Contents
- Herceptin: A Turning Point in Breast Cancer Treatment
- Subsequent Advanced Therapies
- A Quantum Leap: Trastuzumab Deruxtecan (T-DXd)
- The Future of Breast Cancer Care
Herceptin: A Turning Point in Breast Cancer Treatment
One of the earliest and most significant breakthroughs in targeted breast cancer therapy was the development of Herceptin (trastuzumab). This revolutionary drug, pioneered by a team of scientists at UCLA Health led by Dr. Dennis Slamon, director of Clinical and Translational Research at UCLA Health Jonsson Comprehensive Cancer Center, has saved an estimated 3 million lives globally since its approval in 1998.
Herceptin specifically targets the HER2 protein, which is overexpressed in about 25-30% of breast cancer cases. By binding to this protein, Herceptin blocks signals that promote cancer cell growth, effectively revolutionizing treatment for HER2-positive breast cancer. Its introduction marked a fundamental shift, moving beyond conventional chemotherapy to a more precise, molecular approach.
Subsequent Advanced Therapies
The success of Herceptin fueled further research, with Dr. Dennis Slamon and his team continuing to lead the charge in identifying and validating new targeted treatments. These efforts led to the adoption of even more sophisticated and precise drugs, expanding the arsenal against breast cancer.
Ibrance (Palbociclib): A New Era for HR+/HER2- Cancer
Following Herceptin, Ibrance (palbociclib) emerged as another transformative therapy. As the first targeted inhibitor of CDK 4/6 enzymes, Ibrance received a “Breakthrough Therapy” designation from the FDA. Its expanded approval in 2017 revolutionized treatment for the most common type of breast cancer: hormone receptor-positive (HR+) and HER2-negative (HER2-) breast cancer.
Ibrance, along with other drugs in its class, represents the biggest advancement in this cancer type since hormonal therapy in the 1970s. These therapies have effectively doubled the number of women who live longer without disease recurrence, marking a significant leap forward in managing advanced breast cancer.
Kisqali (Ribociclib) in Early-Stage Breast Cancer
In a recent development, September 2024 saw the FDA approve Kisqali (ribociclib) for use with hormonal therapy in early-stage (Stage II and III) HR+/HER2- breast cancer patients who face a high risk of recurrence. This expanded approval means a broader range of patients can now benefit from this powerful treatment, which was previously approved only for advanced metastatic breast cancer.
Dr. Dennis Slamon, the lead investigator for the clinical trial that led to this approval, emphasized its importance: “This approval represents a landmark moment in improving breast cancer patient care. It allows us to expand treatment to a greater number of patients, offering a potent option, especially when combined with hormonal therapy, to further reduce the risk of cancer recurrence.” Dr. Slamon’s pioneering research in cancer earned him the prestigious Szent-Györgyi Prize for Progress in Cancer Research in 2024.
A Quantum Leap: Trastuzumab Deruxtecan (T-DXd)
Building on the foundations laid by Herceptin and other targeted therapies, Dr. Aditya Bardia, director of Translational Research Integration and a member of UCLA Health Jonsson Comprehensive Cancer Center, led research into another groundbreaking treatment: Trastuzumab Deruxtecan (T-DXd).
His team’s studies revealed that T-DXd significantly improves progression-free survival compared to traditional chemotherapy, particularly for patients with advanced breast cancer and limited treatment options.
Clinical Study Results: T-DXd Outperforms Chemotherapy
A pivotal study involving 866 patients demonstrated T-DXd’s superior efficacy. Patients receiving T-DXd achieved a progression-free survival rate of 13.2 months, a significant improvement over the 8.1 months observed in those treated with traditional chemotherapy. These crucial findings were published in The New England Journal of Medicine in September 2024.
How T-DXd Differs from Herceptin
T-DXd operates on a more advanced principle than Herceptin. It’s an antibody-drug conjugate (ADC) that links a HER2-targeting antibody directly to a potent chemotherapy agent. This innovative design allows for precise delivery of the chemotherapy drug directly to cancer cells, minimizing damage to healthy cells.
Unlike Herceptin, which was often used alongside chemotherapy as separate treatments, T-DXd integrates both components into a single, targeted dose. As Dr. Aditya Bardia explained, “This combination maximizes efficacy while simultaneously reducing side effects, representing a major therapeutic advance.”
Towards Replacing Chemotherapy with Less Harmful Alternatives
Dr. Bardia articulates a clear vision for the future: “This study confirms that antibody-drug conjugates can achieve superior outcomes with fewer side effects. This is why we are dedicating our efforts to developing more of these immune-oncology treatments, not just for breast cancer but for other cancer types as well.”
T-DXd had previously gained approval for advanced HER2-low tumors. However, the latest study results highlight its potential for earlier use as a viable alternative to chemotherapy for a broader population of patients with advanced breast cancer. Consequently, the FDA granted T-DXd a new approval, further expanding its reach. Its classification as a “Breakthrough Therapy” by the FDA underscores its profound significance in oncology.
The Future of Breast Cancer Care
The relentless pursuit of innovation by institutions like UCLA Health continues to transform the landscape of breast cancer treatment. From Herceptin’s pioneering role to the advanced capabilities of drugs like Ibrance, Kisqali, and T-DXd, each development brings us closer to a future where breast cancer is not only more treatable but also managed with greater precision and fewer burdens on patients.
These breakthroughs underscore the immense potential of targeted therapies to extend lives and enhance the quality of life for millions affected by breast cancer, paving the way for even more personalized and effective treatments in the years to come.
