World Prostate Cancer Day is on June 11 and we wanted to highlight our randomized phase IIZZFIRST Study, designed to evaluate the antitumor activity of the combination of talazoparib, an inhibitor drug of a protein called PARP, enzalutamide and antitumor therapy androgen suppression in patients with hormone-sensitive metastatic prostate cancer who are not candidates for curative treatment.
Prostate cancer is one of the most common tumors in men. Most cases are detected in the early stages and are curable. However, between 5 and 10% of cases are detected when it has already invaded other tissues of the body, which is known as metastatic prostate cancer. For these cases, there are no curative options, so the objective of current treatments is to extend the survival of patients and preserve their quality of life.
In recent years, therapies directed against PARP, a protein involved in the process of repairing damaged DNA inside cells (a process known as DNA Damage Response (DDR)), have led to one of the greatest advances in the cancer treatment. These types of therapies attack cancer cells in patients with certain genetic mutations that prevent DNA alterations from being repaired.
In the ZZFIRST trial, all patients will begin treatment with androgen suppression therapy and the hormonal agent enzalutamide. After eight weeks of treatment with enzalutamide (two treatment cycles of 4 weeks) a random group of patients will be given the PARP inhibitor drug talazoparib.
The main objective of the study is to observe the antitumor activity of this new therapeutic strategy. The answer will be determined based on the levels of prostate specific antigen (PSA) and will serve to define the optimal combination of drugs that allow obtaining the maximum benefit for each patient. This study is a proof of concept with a special interest in obtaining sequential tumor samples during treatment to carry out molecular analysis so as to identify those subgroups of patients that may benefit more from certain drug combinations.
The hypothesis of the study is that the addition of talazoparib to enzalutamide could increase the clinical benefit of the treatment. It is expected that the combination of talazoparib and enzalutamide can extend the clinical benefit of patients, regardless of mutations in the DDR DNA repair pathway.
The secondary objectives of the trial include analyzing the development of resistance to therapy in patients treated with the combination of talazoparib and enzalutamide, correlating the results of molecular analysis with antitumor activity (especially those associated with the existence of defects in DNA repair), and to evaluate the safety and tolerability of the combination with talazoparib.
The ZZFIRST study, which is currently in the recruitment phase, will be developed under the scientific direction of Dr. Joaquín Mateo, medical oncologist at the Vall d'Hebron Institut d'Oncologia (VHIO), in Barcelona, and a total of 54 patients will participate from nine Spanish centers.
Coinciding with World Prostate Cancer Day, we wanted to express our appreciation to the multitude of centers and numerous patients for their participation in trials designed for these types of tumors. Their involvement has allowed for important advances, especially in the treatment of advanced cases of prostate cancer.