Phase III data showed that Inluriyo improves progression-free survival versus standard endocrine therapy.
The FDA has approved the use of Eli Lilly’s imlunestrant, now to carry the brand name Inluriyo, as a second-line treatment for patients with certain types of breast cancer.
Inluriyo is indicated for adult patients with ER-positive and HER2-negative advanced or metastatic breast cancer, who also carry ESR1 mutations. Lilly expects to make Inluriyo available “in the coming weeks,” according to a Thursday news release. A company spokesperson told Endpoints News that a 28-day course of the drug will cost $22,500, which comes out to roughly $293,000 per year.
The drug’s label doesn’t come with a boxed warning, though it does bear precautions for embryo-fetal toxicities.
Supporting Inluriyo’s approval are data from the Phase III EMBER-3 study, which tested the drug in more than 870 patients whose disease progressed after treatment with an aromatase inhibitor. Participants were randomized to receive Inluriyo alone, Inluriyo plus Lilly’s cancer drug Verzenio or an investigator’s choice of endocrine therapy.
Results, presented in December 2024, showed that in patients with ESR1 mutations, Inluriyo improved progression-free survival (PFS) by 38% versus standard endocrine therapy, an effect that was highly statistically significant. Overall survival, something the FDA recently recommended be a primary endpoint when possible, was immature at the time of the analysis but would continue to be evaluated as a secondary endpoint, Lilly said. A posthoc analysis of the study also hinted at Inluriyo’s ability to reduce central nervous system progression, though a statistical analysis could not be carried out due to low event numbers.
Meanwhile, comparing a combination versus monotherapy regimen of Inluriyo showed that using the drug with Verzenio led to significantly better PFS, regardless of participants’ ESR1 mutation status.
Taken orally once-a-day on an empty stomach, Inluriyo belongs to a class of drugs called oral selective estrogen receptor degrader, or SERDs. These agents work by targeting the estrogen receptor and tagging them for destruction. In turn, this mechanism prevents the estrogen-mediated growth and proliferation of cancer cells, while also sidestepping the treatment resistance typically observed with other endocrine therapies.
Arguably the most well-known SERD is AstraZeneca’s Faslodex, which was approved in 2002 for breast cancer and is administered via an intramuscular injection. In recent years, drugs like Inluriyo have pushed for an oral route of administration to make treatment easier for patients.
Joining this effort is Roche, which on Monday notched a Phase III win for giredestrant in the same indication as Inluriyo. While the pharma did not provide specific data, it noted that giredestrant plus the chemotherapy drug everolimus significantly improved PFS in patients as compared with standard-of-care endocrine therapy plus everolimus.
