The Medicines and Healthcare products Regulatory Agency (MHRA) has approved imlunestrant tosylate, marketed as Inluriyo, for the treatment of certain adults with locally advanced or metastatic breast cancer.

The marketing authorisation was granted on February 24, 2026, to Eli Lilly Nederland B.V.

Inluriyo is indicated for adult patients with oestrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer that has progressed following at least one line of hormonal therapy. The treatment is specifically approved for patients whose tumours carry mutations in the ESR1 gene.

Imlunestrant works by binding to oestrogen receptors in cancer cells, leading to their breakdown and blocking their activity. Since oestrogen can drive the growth and multiplication of certain breast cancer cells, the medicine aims to slow disease progression and reduce tumour growth. The therapy is administered as a once-daily oral tablet.

Julian Beach, Interim Executive Director of Healthcare Quality and Access at the MHRA, said patient safety remains the agency’s top priority. He noted that the approval offers a new option for adults with recurrent or metastatic breast cancer whose disease has not responded to prior hormone treatments. He added that the medicine’s safety will continue to be closely monitored as its use expands.

The most commonly reported side effects include elevated liver enzymes, fatigue, joint, bone and muscle pain, diarrhoea, increased triglyceride levels, nausea and back pain. The full safety profile will be detailed in the Patient Information Leaflet and Summary of Product Characteristics to be published on the MHRA website within seven days of approval.

The MHRA said it will continue to monitor the medicine’s safety and effectiveness and encouraged patients and healthcare professionals to report suspected adverse effects through the Yellow Card scheme.