Successful Trastuzumab Deruxtecan Treatment After AdjuvantTrastuzumab-Induced Heart Failure: A Case Report
This case report demonstrates that trastuzumab deruxtecan (T-DXd) can be a safe and effective treatment option for recurrent HER2-positive breast cancer in a patient who previously experienced trastuzumab-induced heart failure, provided that cardiac function has sufficiently recovered and is closely monitored.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Breast cancer that carries a specific protein on its surface, known as HER2, grows aggressively, but doctors have powerful tools to stop it. One of the most effective treatments is a drug called trastuzumab, which acts like a targeted key to lock down the cancer's growth signals. However, this key can sometimes jam the heart's engine. In a small number of patients, the treatment causes the heart muscle to weaken, a condition known as cardiotoxicity, forcing doctors to stop the life-saving cancer therapy. For years, the medical community faced a difficult question: if a patient's heart recovers after stopping the drug, can they safely return to HER2-targeted treatments if the cancer comes back? The answer was unclear, leaving many patients without a clear path forward when their disease returned.
This story begins with a seventy-nine-year-old woman who had successfully treated breast cancer twenty-three years prior. Seven years ago, the cancer returned, this time with a specific profile that made her a candidate for HER2-targeted therapy. She underwent surgery and began a rigorous regimen of chemotherapy combined with trastuzumab and another drug, pertuzumab. The treatment worked well at first, but during the second cycle of maintenance therapy, she developed sudden shortness of breath. An ultrasound of her heart revealed that its pumping strength, measured as the left ventricular ejection fraction, had dropped from a healthy sixty percent down to thirty-three percent. This severe decline meant her heart was struggling to circulate blood effectively. She was hospitalized for a week, and the medical team immediately stopped the HER2-targeted drugs. Under careful heart failure management, her cardiac function slowly healed, returning to the sixty percent range over seven months.
Four years after her surgery, the cancer returned again, this time spreading to her liver and lymph nodes. The medical team faced a critical crossroads. Her heart had recovered, but her cardiologist advised against restarting the original HER2-targeted therapy due to the risk of the heart failing again. Without these drugs, the doctors tried other treatments, including hormone therapy and different chemotherapies, but the cancer continued to grow. The patient, who wished to avoid the hair loss common with many cancer drugs, tried several alternatives, yet the disease progressed. With few options left and the cancer spreading, the team considered a newer drug called trastuzumab deruxtecan. This medication is a sophisticated version of the original drug, designed to deliver a potent cancer-killing agent directly to the tumor cells while minimizing exposure to healthy tissue. Although it shares the same targeting mechanism as the drug that previously hurt her heart, its structure limits how much of the toxic payload reaches the heart muscle.
The decision to use this new drug was a calculated risk, balancing the need to stop the cancer against the history of heart failure. The patient began treatment, and for the first ten months, the results were remarkable. She received thirteen cycles of the drug over a ten-month period. During this time, her heart remained stable; the pumping strength did not drop, and she showed no signs of heart failure. The cancer responded well, shrinking and staying controlled for a sustained period. However, the treatment was not without challenges. Four months into the therapy, she developed a lung condition known as interstitial lung disease, a known side effect of this specific drug. The medical team paused the treatment, managed the lung issue, and then resumed the drug at a lower dose. Throughout this entire process, her heart function remained secure, proving that the drug could be used safely in a patient with her specific history.
The patient continued to live with her family, fulfilling a personal wish to see her grandchild, and remained active until the very end of her life. When the cancer eventually progressed again, she received other treatments, but the period of stability provided by the new drug allowed her to spend meaningful time with her loved ones. She remained ambulatory at her final treatment visit but died at home one week later. Her family later expressed deep gratitude to the medical team, noting that the care she received allowed her to maintain her quality of life during her final stage. This case demonstrates that for patients who have recovered from heart damage caused by earlier HER2 treatments, a newer, more targeted drug can offer a viable path forward. It suggests that with careful monitoring by both cancer and heart specialists, the fear of heart damage does not have to permanently block access to effective cancer therapies. The recovery of the heart function allowed for the safe return of HER2-directed treatment, offering a durable response without further harm to the heart.
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