The Medicines and Healthcare products Regulatory Agency (MHRA) has approved imlunestrant tosylate (Inluriyo), offering a new treatment option for adults with ER-positive, HER2-negative breast cancer whose disease has progressed despite prior hormone therapy.
The approval applies to patients with locally advanced or metastatic breast cancer who carry specific ESR1 gene mutations and have not responded to at least one line of standard hormone-based treatments.
How Inluriyo Works
Breast cancer cells with estrogen receptors (ER) rely on estrogen to grow and multiply. Imlunestrant binds to these receptors, breaking them down and preventing them from functioning. By blocking and degrading estrogen receptors, Inluriyo can slow tumor growth, limit cancer spread, and help destroy cancer cells. The treatment is administered as a daily oral tablet.
Safety and Side Effects
Julian Beach, Interim Executive Director of Healthcare Quality and Access at the MHRA, emphasized patient safety:
“Patient safety is our top priority. The approval of imlunestrant tosylate (Inluriyo) provides a new treatment for adults with recurrent or metastatic breast cancer after prior hormone treatment hasn’t been effective. As with all licensed medicines, we will continue to monitor its safety closely as it becomes more widely used.”
The most common side effects reported with Inluriyo include:
- Elevated liver enzymes
- Fatigue
- Joint, bone, and muscle pain
- Diarrhea
- Increased triglyceride levels
- Nausea
- Back pain
A complete list of side effects will be available in the Patient Information Leaflet (PIL) and the Summary of Product Characteristics (SmPC) on the MHRA website within seven days of approval.
