Evaluating the effectiveness and safety of talazoparib for the treatment of patients with metastatic castration-resistant prostate cancer.

This study evaluated the effectiveness and safety outcomes of talazoparib (Talzenna) for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) with mutations in DNA repair genes. The data showed that talazoparib was effective with manageable side effects for these patients.

mCRPC is an aggressive form of PC that has spread beyond the prostate gland and is no longer responsive to hormonal therapy such as androgen-deprivation therapy (ADT). ADT reduces the production of androgens (male sex hormones such as testosterone). Reducing these androgens prevents cancer cell growth.

Talazoparib is a targeted therapy that blocks a protein called PARP, which helps damaged cells to repair themselves. Therefore, PARP inhibitors like talazoparib keep cancer cells from repairing themselves which eventually causes them to die. It is used for the treatment of breast cancer which is BRCA mutation-positive (abnormal gene) and HER2 negative. However, the effectiveness and safety outcomes of talazoparib for patients with mCRPC with mutations in DNA repair genes are still unknown.

This study involved a total of 127 men with mCRPC who received at least one dose of talazoparib. The average follow-up time was 16.4 months. The average duration of talazoparib treatment was 6.1 months.

The average overall survival was 16.4 months. The objective response rate (ORR; partial or complete disappearance of cancer) was 29.8%. The average time until patients responded to treatment was 3.4 months. The average duration of response was 12.8 months. 

The most common treatment-related side effects were low white blood cell counts (8%), low red blood cell counts (31%), and low platelet counts (9%).

This study concluded that talazoparib was effective with manageable side effects for patients with mCRPC with mutations in DNA repair genes.

The sample size was very small and had no control group. This study was funded by Pfizer, the manufacturers of talazoparib.