It’s been seven years since Pfizer scored an expansion for its breast cancer blockbuster Ibrance, and during that time, the drug has started to lag sales of two others in its class—Eli Lilly’s Verzenio and Novartis’ Kisqali.
But on Wednesday, the FDA gave the CDK4/6 inhibitor a shot in the arm, signing off on Ibrance as a maintenance option for patients with HR-positive, HER2-positive locally advanced or metastatic breast cancer after induction treatment.
CDK4/6 inhibitors such as Ibrance are well-established treatments for HR-positive, HER2-negative breast cancer, but the HR+/HER2+ indication represents a new frontier.
“With today’s FDA approval, Ibrance becomes the first and only CDK4/6 inhibitor indicated for patients with HR+ metastatic breast cancer regardless of HER2 status, extending its impact to patients who continue to face challenges with treatment resistance," Aamir Malik, Pfizer's U.S. commercial chief, said in a Jun. 24 statement.
Ibrance is cleared for the new use in combination with a standard-of-care regimen, which includes Roche’s Herceptin (trastuzumab), with or without Perjeta (pertuzumab), in addition to endocrine therapy.
Paving the way for the expansion were results from the phase 3 Patina study, which showed that Ibrance added to standard of care reduced the risk of disease progression or death by 24% in the specific patient population following induction treatment, Pfizer said in a Wednesday press release.
The Ibrance combo also extended the median progression-free survival time of patients by 15.2 months to 44.3 months.
The results ended a losing streak for Ibrance, which had come up short in the phase 3 Paloma-2 trial in first-line HR-positive/HER2-negative breast cancer in 2022 and simultaneously flunked a pair of post-surgery adjuvant studies.
In October of last year, Pfizer also scored in a phase 3 breast cancer trial with Tukysa, the HER2-targeted tyrosine inhibitor that the company gained in its $43 billion acquisition of Seagen.
In the study of patients with HER2-positive metastatic breast cancer, Tukysa significantly prolonged the time before disease progression or death versus placebo when added to the standard maintenance regimen of Herceptin and Perjeta.
In 2015, Ibrance became the first CDK4/6 inhibitor to reach the market. Its sales peaked in 2020 at $5.4 billion. Last year, Pfizer reported that the oncology blockbuster's sales had slid to $4.1 billion.
Meanwhile, Lilly's Verzenio and Novartis' Kisqali, which both reached the CDK4/6 breast cancer market in 2017, topped Ibrance for the first time in 2024 and 2025, respectively. Last year, Verzenio generated $5.7 billion while Kisqali pulled in $4.8 billion.