Real-world treatment patterns and clinical outcomes in patients receiving palbociclib combinations for HR+/HER2- advanced/metastatic breast cancer in Japan: Results from the IRIS study.

BACKGROUND: The incidence of breast cancer is rising in Japan, particularly in postmenopausal women. The CDK 4/6 inhibitor palbociclib has demonstrated efficacy in clinical studies in patients with hormone receptor-positive (HR+), human epidermal growth factor 2 (HER2)-negative advanced/metastatic breast cancer (ABC/MBC). The Ibrance Real World Insights (IRIS) study (NCT03159195) collected real-world data for palbociclib-treated patients in several countries including Japan, where such data are currently scarce. METHODS: IRIS was a retrospective chart review study of patients with confirmed HR+/HER2- ABC/MBC receiving palbociclib according to approved indications in real-world clinical practice. In Japan, physicians each abstracted data from patient medical records for up to eight sequential patients treated with palbociclib plus an aromatase inhibitor (P+AI) or fulvestrant (P+F). Outcomes included progression-free rates (PFRs) and survival rates (SRs). RESULTS: Fifty-eight physicians abstracted data for 170 patients receiving palbociclib in the first (64.1%) or second or later line (35.9%), in combination with AI (51.2%) or fulvestrant (48.8%). Median follow-up was 10.4 months. Most patients were initiated on palbociclib 125 mg/d (P+AI, 63.2%; P+F, 78.3%). PFRs at 12 and 24 months were 76.2% and 52.6%, respectively, for P+AI and 71.6% and 65.6%, respectively for P+F. PFRs at 12 and 24 months were 85.4% and 66.5%, respectively, for first-line palbociclib combinations and 56.4% and 50.7%, respectively, for second- or later-line palbociclib combinations. CONCLUSIONS: In this analysis of the Japanese IRIS cohort, outcomes in terms of PFRs and SRs appear to be better with first- versus second or later-line palbociclib, regardless of the endocrine partner.

Real-world treatment of patients with palbociclib for HR+/HER2-advanced/metastatic breast cancer: the Europe IRIS study.

Aim: To report the Europe Ibrance Real World Insights study findings. Methods: Physicians abstracted demographic/clinical characteristics, treatment and outcomes data for women with HR+/HER2- locally advanced breast cancer (ABC) or metastatic  breast cancer (MBC) receiving palbociclib + aromatase inhibitor (AI) or palbociclib + fulvestrant. Kaplan-Meier analysis estimated progression-free rates (PFRs) and survival rates (SRs). Results: 238 physicians abstracted data for 1723 patients. For patients (>90%) initiating at 125 mg/day, dose was reduced in 18.9% of palbociclib + AI and 12.3% of palbociclib + fulvestrant patients. At 12 months, PFR for palbociclib + AI was 88.1%, and SR was 97.3%; PFR for palbociclib + fulvestrant was 79.8%, and SR was 97.5%. Conclusion: Low dose-reduction rates and favorable PFRs and SRs suggest that palbociclib + AI/fulvestrant is well tolerated and effective for HR+/HER2- ABC/MBC in real-world clinical practice.

Lay abstract We describe findings of the Europe Ibrance Real World Insights study. Patients were women with a common type of breast cancer that had worsened but not spread or that had spread. Doctors collected medical information about the women and looked at their progress while on treatment. The treatment was either palbociclib + an aromatase inhibitor or palbociclib + fulvestrant. Two hundred thirty-eight doctors collected information on 1723 women. More than 90% of women started this treatment at a dose of 125 mg/day; the dose was reduced for fewer than 20% of women. At 12 months, more than 80% of women survived without their breast cancer worsening, and more than 97% of women survived. These good results suggest that this treatment is safe and effective for women with breast cancer that had worsened but not spread or that had spread.