Pfizer Inc., in collaboration with Alliance Foundation Trials, LLC (AFT), has shared outcomes from the phase 3 PATINA trial. The investigation highlighted that incorporating Ibrance (palbociclib) into the existing standard first-line maintenance treatment (post induction chemotherapy) significantly boosted progression-free survival (PFS) based on assessment by investigators in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC). Sponsored by AFT, the trial revealed a median PFS of 44.3 months (95% CI: 32.4-60.9) for those administered Ibrance alongside anti-HER2 therapy (trastuzumab or trastuzumab plus pertuzumab) and endocrine treatment versus 29.1 months (95% CI: 23.3-38.6) for those receiving solely anti-HER2 therapy and endocrine treatment [HR: 0.74 (95% CI, 0.58-0.94); unstratified 1-sided p= 0.0074], marking a PFS extension exceeding 15 months. Comprehensive survival insights, a secondary endpoint, remain to be matured for accurate analysis. These findings were presented at the late-breaking oral session (Abstract GS2-12) of the 47th San Antonio Breast Cancer Symposium (SABCS) in San Antonio, Texas.
“PATINA stands as the pioneering large phase 3 study highlighting the advantage of CDK4/6 inhibition for HR-positive, HER2-positive metastatic breast cancer,” noted Otto Metzger, M.D., principal investigator for Alliance Foundation Trials and Medical Oncologist at Dana-Farber Cancer Institute. “The outcomes endorse this maintenance treatment’s potential to decelerate disease advancement and enhance clinical results within this patient group.”
Around 10% of all breast cancers are characterized as HR+, HER2+, alternatively named double-positive or triple-positive breast cancer. Despite medical progress, resistance to anti-HER2 and endocrine therapies remains an obstacle, necessitating innovative therapeutic approaches for HR+, HER2+ MBC. Ibrance is not presently sanctioned for HR+, HER2+ MBC.
“As the first CDK4/6 inhibitor, Ibrance transformed HR-positive, HER2-negative metastatic breast cancer treatment and has served over 773,000 patients since its 2015 debut,” stated Roger Dansey, M.D., chief development officer of oncology at Pfizer. “The findings reveal promising potential for Ibrance alongside standard care for maintenance therapy in HR-positive, HER2-positive conditions. PATINA reaffirms Pfizer’s dedication to addressing the unfulfilled needs facing breast cancer patients, with plans to engage regulatory bodies concerning these results.”
The safety and tolerability of Ibrance in the PATINA trial mirrored its established safety profile in HR+, HER2-negative MBC, with no novel safety signals detected. Common adverse effects included hematologic toxicities like neutropenia and leukopenia; non-hematologic side effects such as fatigue, stomatitis, and diarrhea were generally mild to moderate.
Since obtaining initial regulatory approval in 2015, Ibrance has remained a standard first-line treatment for HR+, HER2- MBC, approved in over 108 countries globally. Pfizer intends to present the PATINA findings to regulatory bodies.
The PATINA (AFT-38) trial is a randomized, open-label phase 3 exploration assessing both the efficacy and safety of Ibrance (palbociclib) combined with anti-HER2 therapy (trastuzumab or trastuzumab plus pertuzumab) plus endocrine therapy as opposed to anti-HER2 therapy and endocrine therapy alone as initial maintenance treatment (subsequent to induction chemotherapy) for hormone receptor-positive (HR+), human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer (MBC) patients. While financially supported by Pfizer, the PATINA study is backed by Alliance Foundation Trials, LLC (AFT) in partnership with six global cancer research entities across the US, France, Germany, Italy, Spain, Australia, and New Zealand.
Participants previously treated with anti-HER2 therapy were randomly assigned to receive Ibrance, in addition to anti-HER2 therapy and endocrine therapy (n=261), or solely anti-HER2 therapy plus endocrine therapy (n=257). The primary focus is progression-free survival (PFS) as determined by the investigator, alongside overall survival as a secondary measure.
Ibrance functions as an oral CDKs 4 and 6 inhibitor, essential for cell cycle regulation and cellular progression initiation. Within the US, Ibrance is prescribed for adult patients with HR+, HER2- advanced or metastatic breast cancer in combination with an aromatase inhibitor for initial endocrine-based treatment in postmenopausal women or men; or with fulvestrant for disease progression post-endocrine therapy.
Alliance Foundation Trials, LLC (AFT) serves as a research body orchestrating and executing cancer clinical trials closely with Alliance for Clinical Trials in Oncology (Alliance) scientific researchers and associated institutional networks, research partners, and non-NCI funding contributors.