We describe the clinical and therapeutic course of a 51-year-old woman with HER-2+
breast cancer who developed leptomeningeal (LM) and spinal cord
metastases after 8 years of stable disease on combination
therapy with intravenous (IV)
trastuzumab. Due to progressive
CNS disease, intrathecal (IT)
trastuzumab was introduced to enhance HER-2+
therapy into the CSF space. A combination HER-2+ targeted approach achieved clinical remission with stable disease in our patient 46 months after she was diagnosed with LM
metastases. However, spinal cord C-1
metastasis was not fully controlled with IT
trastuzumab, ultimately leading to the patient's respiratory compromise. In our patient, IT
trastuzumab immunotherapy improved prognosis and was an effective strategy to manage HER-2+ LM disease. Given alone or alongside other anti-HER-2+
therapeutics with sufficient CNS penetration, IT
trastuzumab could extend the lifespan of patients with leptomeningeal and CNS
metastases.