Here are brief reports on three oncology approvals by the U.S. Food and Drug Administration (FDA) in September 2025:
• Estrogen Receptor Antagonist in Advanced or Metastatic Breast Cancer: The FDA has approved imlunestrant (Inluriyo), an estrogen receptor antagonist, for adults with estrogen receptor (ER)-positive, HER2-negative, estrogen receptor 1 (ESR1)-mutated advanced or metastatic breast cancer after at least one line of endocrine therapy. The FDA also approved the Guardant360 CDx assay as a companion diagnostic device to identify patients who have breast cancer with ESR1 mutations for imlunestrant treatment.
Efficacy was evaluated in EMBER-3, a multicenter trial of 874 patients with ER-positive, HER2-negative locally advanced or metastatic breast cancer previously treated with an aromatase inhibitor either alone or in combination with a CDK4/6 inhibitor. Patients were randomly assigned 1:1:1 to receive imlunestrant, an investigator’s choice of endocrine therapy (fulvestrant or exemestane), or an additional investigational combination regimen.
In the ESR1-mutated population (n = 256), a statistically significant difference in investigator-assessed progression-free survival for imlunestrant compared with investigator’s choice of endocrine therapy was observed. The median progression-free survival was 5.5 months in the imlunestrant arm and 3.8 months in the investigator’s choice arm (hazard ratio = 0.62. 95% confidence interval [CI] = 0.46–0.82; P = .0008). The objective response rate was 14.3% in the imlunestrant arm and 7.7% in the investigator’s choice arm. At the time of the progression-free survival analysis, overall survival data were immature, with 31% of deaths occurring in the ESR1-mutated population.
The most common adverse events (occurring in at least 10% of patients receiving imlunestrant) were decreased hemoglobin, musculoskeletal pain, decreased calcium, decreased neutrophils, increased aspartate transaminase, fatigue, diarrhea, increased alanine transaminase, increased triglycerides, nausea, decreased platelets, constipation, increased cholesterol, and abdominal pain. The recommended imlunestrant dose is 400 mg orally once daily until disease progression or unacceptable toxicity.
• Intravesical System for Non–Muscle-Invasive Bladder Cancer: The FDA has approved the gemcitabine intravesical system (Inlexzo) for adults with bacillus Calmette-Guérin (BCG)-unresponsive non–muscle-invasive bladder cancer with carcinoma in situ with or without papillary tumors. The gemcitabine intravesical system is co-packaged with a urinary catheter and stylet used for insertion through the urinary catheter into the bladder.
Efficacy was evaluated in cohort 2 of SunRISe-1, a single-arm, multicenter trial that enrolled 83 patients with BCG-unresponsive non–muscle-invasive bladder cancer with carcinoma in situ with or without papillary tumors following transurethral resection (TURBT). The complete response rate with the gemcitabine intravesical system was 82%; 51% of patients with a complete response had a duration of response lasting at least 12 months.
The prescribing information includes warnings and precautions when administering the gemcitabine intravesical system in patients with a perforated bladder, metastatic bladder cancer with delayed cystectomy, and magnetic resonance imaging safety.
The gemcitabine intravesical system delivers 225 mg of gemcitabine into the bladder. The gemcitabine intravesical system is inserted once every 3 weeks for up to 6 months (eight doses), followed by once every 12 weeks for up to 18 months (six doses), or until persistent or recurrent high-grade non–muscle-invasive bladder cancer, disease progression, or unacceptable toxicity.
• Kinase Inhibitor for Neurofibromatosis Type 1: The FDA has approved selumetinib (Koselugo) granules and capsules for pediatric patients aged 1 year and older with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas. The FDA previously approved selumetinib capsules for pediatric patients aged 2 years and older with NF1 who have symptomatic, inoperable plexiform neurofibroma.
The approval was based on adequate bridging between the oral granule and approved capsule formulations in a relative bioavailability study in healthy adults (Study 89) and exposure matching between the pediatric patient populations in the SPRINT phase II Stratum I study (capsule formulation, ≥ 2 years of age) and the SPRINKLE study (oral granule formulation, ≥ 1 year of age). Similar exposure between the formulations supports extrapolation of efficacy from pediatric patients ≥ 2 years of age to ≥ 1 year of age.
The selumetinib prescribing information includes warnings and precautions for cardiomyopathy; ocular, gastrointestinal, and skin toxicity; increased creatine phosphokinase; and increased levels of vitamin E and increased bleeding risk (capsule formulation).
