For many men diagnosed with advanced prostate cancer, one of the biggest concerns is how long treatment will continue working.
Although hormone therapy can slow the disease for years, prostate cancer often finds ways to adapt and eventually becomes resistant. Once this happens, treatment becomes more complicated and the risk of disease progression increases.
Researchers at Huntsman Cancer Institute at the University of Utah have reported promising new results that could help delay this process for a specific group of patients. Their study suggests that combining two targeted cancer drugs can significantly extend the period during which advanced prostate cancer remains under control.
The research was published in the New England Journal of Medicine following the successful completion of the TALAPRO-3 Phase III clinical trial.
The study focused on men with metastatic castration-sensitive prostate cancer. In this stage of the disease, cancer has already spread beyond the prostate gland but still responds to hormone-lowering treatment. Doctors often refer to this as an earlier stage of advanced prostate cancer because the disease has not yet developed resistance to hormone therapy.
Not all prostate cancers behave the same way. Some tumors carry genetic changes that make them more aggressive. Mutations in genes such as BRCA1 and BRCA2 are among the best-known examples. These genes normally help repair damaged DNA inside cells. When they are altered, cancer cells may grow more aggressively and become harder to treat.
The TALAPRO-3 trial enrolled men whose tumors carried these types of DNA repair gene mutations. Researchers wanted to determine whether adding a targeted DNA repair drug to standard treatment could improve outcomes.
The first treatment used in the study was enzalutamide, a medicine that blocks prostate cancer cells from responding to male hormones. Since prostate cancer often relies on these hormones to grow, blocking their effects can slow disease progression.
The second treatment was talazoparib, a PARP inhibitor. PARP inhibitors work by interfering with the ability of cancer cells to repair damaged DNA. Because tumors with BRCA and related mutations already have weaknesses in their DNA repair systems, blocking PARP can make it much harder for these cancer cells to survive.
A total of 599 patients participated in the trial. Some received enzalutamide alone, while others received the combination of enzalutamide and talazoparib.
The combination produced a clear benefit. Researchers found a 52% reduction in the risk of disease progression or death among patients receiving both drugs. This is considered a major improvement in cancer treatment outcomes.
The researchers also examined radiographic progression-free survival, a measure that tracks how long patients live without visible signs of cancer growth on imaging scans. After three years, 77% of patients receiving the combination treatment remained free of visible disease progression. Among those receiving enzalutamide alone, the rate was 56%.
For patients and their families, this difference can be highly meaningful. Delaying progression means delaying the point at which cancer becomes more difficult to treat. It may also provide additional time with better disease control and fewer cancer-related complications.
The study delivered another encouraging message. Most patient-reported quality-of-life measures remained stable despite the addition of a second therapy. This suggests that the improved effectiveness did not substantially reduce patients’ day-to-day well-being.
The findings also emphasize the growing role of genetic testing in modern cancer care. Without testing, doctors may not know which patients carry DNA repair gene mutations. Identifying these mutations allows physicians to select treatments that specifically target the weaknesses of an individual tumor.
According to the researchers, approximately 25% to 30% of patients with metastatic castration-sensitive prostate cancer have these types of genetic alterations. This means a substantial number of patients may be candidates for the combination approach.
The TALAPRO-3 results build on earlier success from the TALAPRO-2 study, which investigated the same drug combination in patients whose cancers had already become resistant to hormone therapy. Those earlier findings led to FDA approval of the treatment in 2023 for certain advanced prostate cancer patients.
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Source: University of Utah Huntsman Cancer Institute.
