NEW YORK CITY — Pfizer said on Tuesday its experimental combination reduced the risk of disease progression or death by 40% in patients with breast cancer.
Pfizer's atirmociclib in combination with fulvestrant, a hormone therapy, was being tested in a mid-stage study in patients whose cancer had spread and had received prior treatment.
The experimental drug combo was being compared to fulvestrant or everolimus plus exemestane, a widely used targeted therapy regimen for postmenopausal women with the common type of breast cancer
Pfizer said the study enrolled patients whose cancer returned soon after treatment with widely used CDK4/6 drugs, a group that is harder to treat.
The company said more than 90% of patients started atirmociclib within three months of stopping their previous cancer medicine.
The drug had a manageable safety profile, with 6.4% of patients stopping treatment due to side effects, Pfizer said.
The company said overall survival data, a secondary goal, were still early and not ready for conclusions at this stage.
Pfizer said the results support plans to test atirmociclibin first-line and early-stage of breast cancer, where longer-lasting disease control could help more patients.
Atirmociclib is an experimental oral drug that targets CDK4, a cell-cycle protein that drives tumor growth.
The company said a large late-stage study of the drug in newly diagnosed metastatic breast cancer patients is already underway.
