FDA Approves New Treatment for Advanced Breast Cancer

The U.S. Food and Drug Administration has green-lighted a new option for treating advanced breast cancer. Eli Lilly announced the approval of Inluriyo, which is an oral estrogen receptor antagonist, on September 25. This drug is aimed at adults suffering from specific types of the disease.

These types include estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2–), and ESR1 altered progressive or metastatic breast cancer.

A New Hope for Patients

According to a press statement, this once-daily pill is for patients who have experienced disease progression following at least one prior endocrine (hormonal) therapy. In the Phase 3 EMBER-3 trial, Inluriyo demonstrated a 38% reduction in the risk of cancer advancement or mortality when compared to traditional endocrine treatments.

Patients with ESR1-degenerate breast cancer had a significant boost in progression-free survival from this therapy, outpacing other hormonal treatments like Fulvestrant and Exemestane, with median survival times of 5.5 and 3.8 months, respectively.

Eli Lilly explains that certain cancers develop mutations that can fuel unrestrained growth. Inluriyo targets these receptors, working to curb their activity and thus slow down disease progression.

Dr. Komal Jhaveri from the Memorial Sloan Kettering Cancer Center highlighted how this advancement is promising, especially for patients with the ESR1 mutation—found in nearly half of those receiving hormone therapy and often linked to treatment resistance. He noted the drug’s efficacy, tolerability, and convenience can greatly enhance treatment options for these patients.

However, there are precautions. Inluriyo comes with a warning regarding potential risks to a fetus, which means women who are pregnant or planning to conceive should consult their healthcare providers beforehand.

During the Phase 3 trial, common side effects were noted as relatively mild but included lab abnormalities, musculoskeletal pain, fatigue, gastrointestinal issues, and changes in blood chemistry. Approximately 4.6% of patients had to stop the treatment because of these issues, while 2.4% opted for a reduced dose.

A Step Forward

Jacob Van Narden, a vice president at Lilly Oncology, expressed optimism about this therapy, indicating it marks significant progress for patients battling breast cancer. Inluriyo is also participating in an ongoing Phase 3 trial for patients with early-stage ER+ and HER2-negative breast cancer, which plans to enroll about 8,000 participants globally.

Lilly anticipates Inluriyo will be available in the U.S. in the coming weeks.

Dr. Nicole Saphier, a radiologist and breast imaging director at the Memorial Sloan Kettering Cancer Center, commented on the FDA’s approval, noting its significance for patients who develop resistance to first-line therapies. She emphasized the importance of remaining vigilant about potential safety risks associated with the treatment.