Pfizer says experimental breast cancer drug cuts risk of disease worsening in mid-stage trial

Pfizer said on Tuesday its experimental combination reduced the risk of ​disease progression or death by 40% in ‌patients with breast cancer. Here are some ​details:

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 ‌atirmociclib in 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.