FDA Approves New Therapy for Advanced Breast Cancer

The Food and Drug Administration on Sept. 25 approved a new therapy for advanced breast cancer, based on data from a phase 3 clinical trial.

Regulators said in a statement that they approved imlunestrant, also known as Inluriyo, from Eli Lilly.

The therapy, an estrogen receptor antagonist, is cleared for adults who have advanced or metastatic breast cancer with estrogen receptor-1 mutations.

Metastatic breast cancer, also called Stage IV breast cancer, occurs when the disease has spread beyond the breast and nearby lymph nodes to other parts of the body, most commonly the bones, lungs, liver, or brain.

Some breast cancers develop estrogen receptor-1 mutations, which make estrogen receptors overly active. These receptors normally help regulate cell growth, but when mutated, they can drive cancer progression.

Inluriyo is designed to target these overactive receptors by binding to the estrogen receptor, blocking its activity, and breaking it down to help slow the spread of the disease.

A phase 3 randomized, open-label trial with 874 patients that compared imlunestrant to a different investigational regimen, found that participants who received the therapy were more likely to survive and not have any cancer progression.

Among participants with estrogen receptor-1 mutation, median progression-free survival was 5.5 months in the therapy arm, compared to 3.8 months in the other arm, according to results posted to clinicaltrials.gov.

“We are deeply grateful to the patients, investigators, Lilly team members and clinical care teams who made this advancement possible. This therapy has the potential to make the treatment journey more manageable for those living with breast cancer,” Jacob Van Naarden, executive vice president and president of Lilly Oncology, said in a statement.

“With its demonstrated efficacy, tolerability profile and oral administration, this therapy provides a meaningful alternative treatment option for this patient population,” added Dr. Komal Jhaveri, clinical director of early drug development at Memorial Sloan Kettering Cancer Center, and the principal investigator of the trial, in a statement released by the company.

Adverse events among imlunestrant participants included abdominal pain and cardiac arrest. The label for the drug warns that it can cause fetal harm when taken by pregnant women, based on findings in animal studies and the drug’s mechanism of action.

The therapy is expected to be available in the United States in the next few weeks, with a list price of $22,500 per 28 days for the 400 milligram dose, according to the company. The therapy is recommended once a day, across two tablets of 200 milligrams each.