ESMO Breast 2021 | Talazoparib in locally advanced or metastatic breast cancer

I will present my presentation about talazoparib in locally advanced or metastatic breast cancer patients experience from an Early Access Program in Turkey.

As you know, BRCA1 and BRCA2 mutations cause the repair mechanism deficiency for DNA double-strand breaks, and the [inaudible] pathway which repairs single-standard breaks is regulated by PARP enzyme.

As you know, talazoparib is a potent PARP inhibitor and resulted in significant prolonged PFS and compared to standard of chemotherapy in EMBRACA Phase III trial with other patients 0.54, and all clinically relevant subgroups demonstrate the reduction in the risk of progression with talazoparib. Overall survival in EMBRACA trial was immature and the response rate was doubled with talazoparib compared to chemotherapy.

In our study, we aim to determine the real-life efficiency safety profile of talazoparib in BRCA-mutant breast cancer patients in Turkey. In our study, advanced breast cancer patients with BRCA1 or BRCA2 mutation who receive talazoparib treatment via Early Access Programs are retrospective analyzed and the data collected from 24 different oncology centers in Turkey. And there were no exclusion criteria for our study.

In baseline characteristics in our study, there were 47 advanced breast cancer patients. 46 was female, and one only male patient in the study population. The median age of our study group past 41 years old, and most of the tumor histology was hormone receptor positive up to 63% and 30, 36% of patients was triple-negative breast cancer patients. And we know that the classification according to the metastatic sites before talazoparib treatment showed that 76% of patients had visceral metastasis. And we know that about 12% of patients had CNS metastasis at the time of diagnosis.

Median follow-up of our trial after 13 months and the median progression-free survival was 6.5 months. And according to the treatment line, we know that 48% of patients treated with first three lines. The rest of the patients, about 51% of patients, received talazoparib after four or later lines. And according to this study, the median progression-free survival was 9.9 months in first three lines and 3.5 months after fourth and later lines. And the objective response rate was 34.7% in first three lines and about 35% in ITT group in our trial. For BRCA1 and BRCA2 subgroups to a median progression-free survival was 12.6 versus 5.1 months respectively.

In conclusion, our results were consistent with the Phase III EMBRACA trial. Our study demonstrated favorable PFS and objective response rates. Results in heavily plated, real-life BRCA-mutant advanced breast cancer patients. And in our study, median progression-free survival was compatible with this result. And moreover, for the patients who received the treatment in first three lines, just like in the EMBRACA study, median progression-free survival was 9.9 months.