Dados do Trabalho

Título

REAL-WORLD TREATMENT OUTCOMES IN METASTATIC HR+ HER2- BREAST CANCER PATIENTS EXPOSED TO CDK4/6 INHIBITORS

Introdução

Cyclin-dependent kinase 4/6 inhibitors (iCDK4/6) have recently been developed and introduced into clinical practice. However, due to the strict criteria used in pivotal trials, the reproducibility of these results in the real-life setting needs to be confirmed, in order to validate the efficacy and safety of this new therapeutic option.

Objetivo

Describe real-world data of iCDK4/6 in the Brazilian population.

Método

We retrospectively analyzed data from patients (PTS) with confirmed HR+/HER2- metastatic breast cancer treated with iCDK4/6: Ribociclib(R), Palbociclib(P), or Abemaciclib(A). A checklist of 191 fields was completed for each patient using the REDCap platform. Outcomes evaluated included, among others, median time to treatment discontinuation (mTTD), median progression-free survival (mPFS), and overall response rate (ORR) by evaluator assessment.

Resultado

Between 01/2015 and 06/2021, 142 PTS were treated with an iCDK4/6 (79 P, 42 R, 21 A). The median age was 59 years, 68.7% had recurrent disease, and concomitant ovarian suppression was used in 34% of PTS. Regarding metastatic sites: 36.7%, 35.4%, 27.9% had 1, 2 or 3+ sites, respectively. 56.5% PTS received iCDK4/6 in first treatment line. Letrozole (45.6%) or Fulvestrant (43.5%) were the most frequently used hormonal agents. The mPFS was 29m (R) vs 22m (P) vs 6m (A), in favor of R (p=0.002), but a higher proportion of PTS received R in the first line setting compared to the other two drugs. However, no difference was seen when the analysis was restricted to the first line scenario (p=0.17). Higher mPFS was statistically correlated with early lines of treatment (p<0.001), lower number of metastatic sites (p=0.002), absence of hepatic metastasis (p<0.001), and normal CEA (p=0.001) and CA 15-3 levels (p=0.001) at the beginning of treatment. Sixty-four PTS required one (34 P, 18 R, 12 A) and 19 needed two dose reductions (13 P, 3 R, 2 A). mTTD was similar among the agents (p=0.072). ORR was 76.2%(R) vs 62% (P) vs 42.9% (A). More patients had complete response with R and P (p=0.009), with no difference for partial response and stable disease (p=0.622). Dose delays occurred in 70% and adverse effects in 94.5% of the population (70% grade 3-4).

Conclusão

Our results confirm the efficacy and tolerability of iCDK 4/6 in routine clinical practice. To our knowledge, this is the first real-world data describing the use of this therapeutic strategy and the first study to compare the efficacy and toxicity of R, P and A in the Brazilian population.

Palavras-chave

Cyclin-dependent kinase 4/6 inhibitors; Real-world data; Brazilian population