Real-world data comparison: the efficacy of enzalutamide and abiraterone acetate in the treatment of mCRPC

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Prostate cancer is the second most common cancer in men in the world.
Most advanced prostate cancer patients will progress to castration-resistant prostate cancer (CRPC) after receiving androgen deprivation therapy (ADT)
.

Enzalutamide and abiraterone acetate are androgen receptor targeted drugs for the treatment of metastatic castration-resistant prostate cancer (mCRPC).
The PREVALIL study and the COU-AA 302 study confirmed the efficacy of the two drugs
.

At present, enzalutamide and abiraterone acetate have been approved in many countries for the treatment of mCRPC patients before chemotherapy
.

However, enzalutamide and abiraterone acetate have no head-to-head phase III clinical studies, which drug has better efficacy and safety, and which drug should be preferred.
It is not yet clear.
Real-world data and more are needed.
The results of large patient groups are discussed
.

In this context, this study compared the baseline characteristics, efficacy, and survival time of enzalutamide and abiraterone acetate in mCRPC patients, and analyzed the effects on imaging progression-free survival (rPFS) and overall survival ( OS) prognostic factors
.

Study introduction The study adopts a retrospective study design and included 250 mCRPC patients from 5 centers (all from Turkey) from 2012 to 2015, receiving enzalutamide 160 mg/day or abiraterone 1000 mg/day combined with prednisone 10mg/day, until disease progression, death or intolerable toxicity occurs
.

Except for patients with bilateral orchiectomy, all patients continued to receive ADT treatment with a serum testosterone level of 50ng/dL (≤2.
0nmol/L)
.

The results of the study are shown in Table 1 for the baseline characteristics of patients
.

For the proportion of patients with metastasis found at the time of diagnosis, the abiraterone acetate group was higher than the enzalutamide group (P=0.
016); for the number of patients without PSA decline, the abiraterone acetate group was higher than the enzalutamide group; In the zalutamide group, the proportion of patients whose PSA decreased by ≥50% was higher (P=0.
020) (Figure 1)
.

After 12 weeks of treatment, compared with the enzalutamide group, the abiraterone group had a higher rate of disease progression and a lower rate of disease stability
.

The median follow-up time was 13 months.
During the follow-up period, the disease progression rate of the abiraterone acetate group (82%) was significantly higher than that of the enzalutamide group (P<0.
001)
.

The benefits of rPFS (P<0.
001) and OS (P=0.
027) in the enzalutamide group were more significant (Figure 2)
.

Table 1 Baseline characteristics of patients Figure 1 Results of PSA reduction Figure 2 Results of rPFS and OS based on the results of subgroup analysis stratified before/after docetaxel treatment, as shown in Table 2, whether before or after docetaxel treatment , The rPFS of enzalutamide group was significantly higher than that of abiraterone acetate group
.

Analysis of OS results found that there was no significant difference in OS between the two groups before docetaxel treatment; after docetaxel treatment, the OS of the enzalutamide group was significantly longer than that of the abiraterone acetate group (Figure 3)
.

Table 2 Subgroup analysis before/after docetaxel treatment Figure 3 Results of rPFS and OS before/after docetaxel treatment Regarding the prognostic factors affecting rPFS and OS, the results of univariate analysis showed that the treatment drug (Enzalutamide or Abiraterone acetate) has a significant impact on the prognosis
.

Other prognostic factors that significantly affect rPFS include age, stratification before/after docetaxel treatment, and PSA decline rate; prognostic factors that significantly affect OS include stratification before/after docetaxel treatment and PSA decline rate
.

The results of multivariate Cox regression analysis showed that age, treatment drugs, PSA decline rate, and metastasis location are independent prognostic factors of rPFS, and independent prognostic factors of OS have not been observed
.

Discussion This study discussed the treatment of rPFS and OS in mCRPC patients with enzalutamide and abiraterone acetate
.

Compared with abiraterone acetate, rPFS and OS in the enzalutamide group had statistically significant advantages, but did not significantly reduce the risk of death
.

The results of the study showed that the overall cohort's rPFS and OS were 12 months and 20 months, respectively, the enzalutamide group was 15 months and 29 months, and the abiraterone acetate group was 7 months and 16 months ( rPFS: P<0.
001; OS: P=0.
027)
.

In the phase III AFFIRM study, patients who had previously received docetaxel treatment, after receiving enzalutamide treatment, the OS and the time to PSA progression were 18.
4 months and 8.
3 months, respectively
.

In the PREVALIL study, the use of enzalutamide for rPFS in patients who had not previously received docetaxel chemotherapy was significantly better than the placebo group (20 vs 5.
4 months), and the study was terminated early
.

In the PREVAIL study, the median OS of the enzalutamide group and the placebo group were 35.
3 months and 31.
3 months, respectively
.

In this study, patients after and before treatment with docetaxel were treated with enzalutamide, rPFS was 11 months and 17 months, and OS was 26 months and 29 months, respectively
.

Although the follow-up time of this study is slightly shorter than that of the AFFIRM study and the PREVALIL study, the results of the study are consistent
.

Study conclusions The study showed that, compared with the abiraterone acetate group, the rPFS and OS of the enzalutamide group were longer
.

The stratification of patients before/after docetaxel treatment showed that before and after docetaxel treatment, the rPFS of the enzalutamide group was significantly better than that of the abiraterone acetate group; and, after the docetaxel treatment, The OS of the enzalutamide group was significantly longer than that of the abiraterone acetate group
.

References: Ayşe Demirci, Cemil Bilir, Burcu Gülbağcı, et al.
Sci Rep.
2021 Jul 8;11(1):14131.