Disparities in receipt of 1-st line CDK4/6 inhibitors with endocrine therapy for treatment of hormone receptor positive, HER2 negative metastatic breast cancer in the real-world setting

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4 Novembre 2024
Pilehvari A, Kimmick G, You W, et al.

Disparities in receipt of 1-st line CDK4/6 inhibitors with endocrine therapy for treatment of hormone receptor positive, HER2 negative metastatic breast cancer in the real-world setting

Breast Cancer Res 2024;26(1):144
Simonpietro Marrocco Issues, Novembre 2024

Messaggi chiave

  • Il presente studio ha utilizzato dati osservazionali real world per confrontare i profili di pazienti con carcinoma mammario metastatico (mBC) HR+/HER2- avviate a trattamento di prima linea con endocrinoterapia (ET) da sola o in associazione a un inibitore delle chinasi CDK4/6 (CDK4/6i) nel periodo febbraio 2015 – novembre 2021.
  • È stato incluso un totale di 3917 pazienti. L’analisi di regressione logistica ha evidenziato una maggior probabilità di trattamento con CDK4/6i + ET nelle fasce di età 50-64 anni (odds ratio [OR], 3,42, IC 95%, 2,41-4,86) e 65-74 anni (OR, 3,18, IC 95%, 1,68-6,02) rispetto a 18-49 anni, nelle pazienti con mBC de novo (OR, 1,37, IC 95%, 1,07-1,76) rispetto a una diagnosi iniziale di tumore in stadio I e in presenza di metastasi viscerali (OR, 1,7, IC 95%, 1,06-1,51) rispetto a solo ossee. Viceversa, la probabilità di trattamento con CDK4/6i + ET è risultata inferiore nelle pazienti di etnia nera (OR, 0,76, IC 95%, 0,58-1,00) rispetto a caucasica, in presenza di una diagnosi iniziale di BC in stadio III (OR rispetto allo stadio I, 0,69, IC 95%, 0,52-0,92) e di un performance status peggiore (PS 1: OR, 0,82, IC 95% 0,69-0,97; PS 2+: OR, 0,50, IC 95%, 0,40-0,62) e nelle pazienti con assicurazione esclusivamente Medicare (OR, 0,73, IC 95%, 0,30-1,78) rispetto a un’assicurazione Medicaid e commerciale combinata.
  • Dopo aggiustamento, l’uso di un CDK4/6i in associazione a ET come trattamento di prima linea è stato associato a un miglioramento statisticamente significativo degli esiti di sopravvivenza libera da progressione (27 vs 17 mesi; hazard ratio [HR], 0,61, p <0,001) e sopravvivenza globale (52 vs 42 mesi; HR, 0,74, p <0,001) rispetto all’ET da sola.
  • I risultati presentati supportano ulteriormente l’uso della combinazione CDK4/6i + ET nel trattamento upfront del mBC HR+/HER2- e sottolineano la crucialità di misure e strategie volte a garantire un accesso più equo a questa importante classe di farmaci.

Abstract

Objective

  • This study used real-world observational data to compare profiles of patients receiving different first-line treatment for hormone receptor positive (ER+), HER2 negative, metastatic breast cancer (MBC): CDK4/6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) versus ET alone.

Method

  • From a nationwide electronic health record-derived Flatiron Health de-identified database including 280 US cancer clinics, we identified patients with hormone receptor positive, HER2 negative, metastatic breast cancer receiving 1st-line therapy with ET alone or CDK4/6i plus ET between February 2015 and November 2021.
  • Patient sociodemographic status, MBC treatment regimen and outcomes were the focus of this analysis.
  • Patient characteristics were compared using t-tests and chi-square tests.
  • Logistic regression analysis was performed to examine the association of patient characteristics with the likelihood of receiving 1st-line CDK4/6i plus ET vs. ET alone.
  • Kaplan-Meier method and Cox proportional hazards were used to test the impact of 1st-line treatment regimen on real-world progression-free survival (PFS) and overall survival (OS).
  • Baseline characteristics were balanced using inverse probability weighting (IPW).

Results

  • The study population included 3,917 patients receiving CDK4/6i plus ET (n = 2170) and ET alone (n = 1747) for their MBC.
  • Compared to patients receiving ET alone, those receiving CDK4/6i plus ET were younger (mean age 66.8 vs 68.6, p <0.001), more likely to present with de novo MBC (p <0.001), had better performance status (50.2 vs 40.5% patients with ECOG value 0, p = 0.001) and lower number of comorbidities (29.7 vs 26.6% ≥ 1 comorbidity, p <0.001).
  • Logistic regression revealed increased odds of CDK4/6i plus ET in individuals aged 50-64 (OR: 3.42, 95% CI [2.41, 4.86]) and 65-74 (OR: 3.18, 95% CI [1.68, 6.02]) versus those aged 18-49 years of age.
  • Black individuals had lower odds of CDK4/6i plus ET (OR: 0.76, 95% CI [0.58, 1.00]) compared to White individuals.
  • Other characteristics associated with lower odds of CDK4/6i plus ET included patients with stage III disease (OR: 0.69, 95% CI [0.52, 0.92]), lower performance status (OR: 0.50, 95% CI [0.40, 0.62]), and Medicare insurance (OR: 0.73, 95% CI [0.30, 1.78]) compared to those with commercial and Medicaid insurance.
  • After IPW adjustment, use of CDK4/6i plus ET as 1st-line treatment was associated with significantly longer median PFS compared to ET alone (27 vs 17 months; hazard ratio [HR] = 0.61, p <0.001).
  • Median OS was 52 months in the CDK4/6i plus ET group and was 42 months with ET alone (HR = 0.74, p <0.001).

Conclusion

  • In this real-world database, disparities in receiving 1st-line CDK4/6 inhibitors were seen by age, diagnosis stage, baseline performance status, comorbidity, and insurance status.
  • In adjusted analysis, the use of 1st-line CDK4/6i plus ET yielded better PFS and OS rates than ET alone.
  • Further efforts are essential to enhance equitable use of and access to this crucial drug class.
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