Real-world implementation of pertuzumab from 2013 to 2023 for de Novo HER2-positive metastatic breast cancer in the Netherlands: a population-based study.

BACKGROUND

We aimed to describe the implementation of pertuzumab and identify factors associated with its use among patients with de Novo HER2-positive metastatic breast cancer (HER2+ MBC) in the Netherlands.

METHODS

Using Netherlands Cancer Registry data, we identified patients diagnosed with de Novo HER2+ MBC in 2013-2023 who received systemic therapy. Pertuzumab uptake by year of diagnosis was assessed, and segmented regression was used to estimate the time point at which a plateau was reached. Factors associated with pertuzumab use during the plateau period were evaluated using multivariable logistic regression, with adjusted odds ratios converted to adjusted relative risks (aRR).

RESULTS

Among 1,982 patients with de Novo HER2+ MBC, pertuzumab use increased from 9% in 2013 to 49% in 2014, 61% in 2016 and 78% in 2018, after which it plateaued at a rate of 78%. In 2018-2023, pertuzumab use was independently associated with age [50-74 years (aRR 0.75, 95% CI: 0.61-0.87) and ≥75 years (aRR 0.04, 95% CI: 0.02-0.07) vs < 50 years]; socioeconomic status [middle (aRR 0.88, 95% CI: 0.75-0.99) and low (aRR 0.80, 95% CI: 0.65-0.94) vs high]; hormone receptor status [positive (aRR 0.46, 95% CI: 0.34-0.60) vs negative disease]; and grade [3 (aRR 1.06, 95% CI: 1.01-1.10) vs 1-2].

CONCLUSION

Pertuzumab uptake reached a plateau five years after approval of reimbursement in the Netherlands. Nowadays, around 80% of patients with de Novo HER2+ MBC received first-line pertuzumab-based therapy. Factors associated with pertuzumab non-use provide important insights for health policymakers aiming to ensure optimal access to effective cancer therapies.