The landscape of advanced breast cancer treatment has expanded with the FDA's 2024 approval of Itovebi (inavolisib) in combination with Ibrance (palbociclib) and Faslodex (fulvestrant). This new therapeutic option targets adults with endocrine-resistant, PIK3CA-mutated, hormone receptor (HR)-positive, HER2-negative locally advanced or metastatic breast cancer, though healthcare providers must carefully monitor specific side effects.
Key Safety Considerations and Side Effects
The INAVO120 trial, which led to the approval, revealed several significant side effects occurring in at least 20% of patients. Notable adverse events included decreased levels of neutrophils, hemoglobin, and platelets, alongside metabolic changes such as increased fasting glucose levels. Patients also experienced stomatitis, diarrhea, and various electrolyte imbalances.
Dr. Yuan Yuan, professor of medicine and director of breast oncology at Cedars-Sinai Medical Center, emphasizes the importance of understanding the treatment's toxicity profile. "There are important toxicity side effect profiles that our audience should be aware of, especially when we hit the PIK3CA pathway, which is also instrumental for our normal physiological metabolism of glucose," she explains.
Blood Sugar Management and Patient Monitoring
A particular concern with Itovebi is its impact on blood sugar levels. The INAVO120 trial implemented strict eligibility criteria, requiring patients to have a hemoglobin A1C less than 6.0. This requirement poses challenges for patients with diabetes, necessitating careful management and monitoring.
"The patient may develop oral mucositis, mouth sores, the patient may have diarrhea," Dr. Yuan notes. "All of these toxicities need to be carefully managed and very carefully treated."
Multidisciplinary Approach to Treatment
Success with Itovebi therapy requires a coordinated healthcare approach. Dr. Yuan emphasizes the need for collaboration: "We will need to work very cohesively with our endocrinologist and try to monitor the patient and [work with] support from nursing, from pharmacy. I think it's all needed in order to have a successful program treating patients on Itovebi."
This integrated care model ensures proper monitoring and management of side effects, particularly for patients with pre-existing diabetes or those who develop treatment-related hyperglycemia.
