Pfizer brings Ibrance to new subset of breast cancer patients, regardless of menopausal status
Pfizer has expanded Ibrance’s use to include a new subset of breast cancer patients, the company slipped into its quarterly earnings report on Tuesday.
The drug was approved in combination with an aromatase inhibitor (AI) in mid-December to treat women with HR-positive, HER2-negative metastatic breast cancer regardless of menopausal status, Pfizer announced.
Ibrance was first approved in postmenopausal women with advanced breast cancer back in 2015. The CDK4/6 inhibitor has since racked up a slate of label expansions, but until the latest add-on, the AI combo treatment was only indicated for postmenopausal women or men.
Regulators requested that Pfizer include pre- and perimenopausal women in the indication back in December 2021, prompting the pharma giant to file a supplemental new drug application (sNDA) last March, according to an approval letter.
“With an estimated 17% of the HR+/HER2- mBC population consisting of peri/pre-menopausal patients, there remained an unmet need for this patient population,” Pfizer said in an email to Endpoints News.
Pfizer tested Ibrance in combination with fulvestrant in women regardless of menopausal status in the Phase III PALOMA-3 study, however 80% of the 521 patients enrolled were postmenopausal, according to the drug’s label. Patients treated with the Ibrance combo in that study saw a median progression-free survival of 9.5 months, compared to a median 4.6 months in the placebo group.
“Consistent PFS results were observed across patient subgroups of disease site, sensitivity to prior hormonal therapy, and menopausal status,” the label states.
Pfizer said the label expansion was based on subgroup analyses from PALOMA-3 and PALOMA-2, another Phase III study in which a subgroup of pre- and perimenopausal women were treated with Ibrance and letrozole following an oophorectomy. Evidence was also included from an investigator-initiated study.
While executives did not mention the new approval in prepared remarks during Pfizer’s Q4 earnings call, CSO Mikael Dolsten did say that the team expects a pivotal readout for Ibrance in HR-positive, HER2-positive breast cancer in the next 18 months.
Global Ibrance sales were down 6% last year, totaling roughly $5.1 billion. While the drug has long been a market leader, rivals from Eli Lilly and Novartis are looking to take a bite out of its market share. Eli Lilly’s Verzenio earned $617 million in Q3, up 84% from the previous year, while Novartis’ Kisqali raked in $327 million, up 49%. Gilead has also filed for approval of Trodelvy in pretreated HR-positive, HER2-negative metastatic breast cancer, and is expecting a decision this month.
Editor’s Note: This story has been updated to include comment from Pfizer.