Drug Combo Effective Against Advanced Prostate Cancer

FRIDAY, Oct. 10, 2025 (HealthDay News) — A new drug combo is offering hope for men with advanced prostate cancer.

Adding the targeted cancer drug niraparib to hormone therapy reduced the risk of prostate tumor growth and slowed symptom advance, according to findings published Oct. 7 in the journal Nature Medicine.

The combination was even more effective among men with genetic mutations driving their prostate cancer, researchers noted.

“Although current standard treatments are very effective for the majority of patients with advanced prostate cancer, a small but very significant proportion of patients have limited benefit,” said lead researcher Dr. Gerhardt Attard, chair of medical oncology with the University College London Cancer Institute.

“By combining with niraparib we can delay the cancer returning and hopefully significantly prolonging life expectancy,” he said in a news release.

Niraparib is a “maintenance” drug approved to keep certain types of cancer from coming back, including ovarian cancer, according to Drugs.com.

The drug, sold under the brand name Zejula, is PARP inhibitor that works by blocking the ability of cancer cells to repair themselves. This increases the odds that the cells will die off.

For this new study, researchers combined niraparib to the standard treatment of abiraterone acetate (Zytiga) and prednisone.

Zytiga blocks production of testosterone, which can fuel prostate cancer growth, while prednisone blocks some side effects that come with treatment.

The study focused on patients with advanced prostate cancer who had alterations to genes involved in an essential type of DNA defect repair, known as homologous recombination repair (HRR).

Faulty HRR-related genes can help cancers grow and spread more aggressively, researchers said in background notes. About 1 in 4 men with advanced prostate cancer have alterations in HRR genes, which include BRCA1, BRCA2, CHEK2 and PALB2.

The clinical trial enrolled nearly 700 advanced prostate cancer patients across 32 countries with a median age of 68. (Half were older, half younger.) More than half (56%) had alterations in their BRCA1 or BRCA2 genes.

Half of the patients received the new combo therapy, and the rest received standard treatment plus a placebo in place of niraparib.

After follow-up of around two and a half years, researchers found that the combo treatment reduced the risk of cancer growth by 37% compared to standard care.

Results were even better among patients with BRCA1 or BRCA2 mutations, reducing by 48% their risk of cancer growth.

The time until symptom progression was twice as long for patients who got niraparib, reducing the share of patients with notable worsening of symptoms from 34% to 16%, researchers found.

There also was a trend toward improved overall survival in the niraparib group, but longer follow-up is needed to confirm that the combo improves life expectancy, researchers said.

The combo also came with more side effects, including significantly more cases of anemia and high blood pressure. About 25% of patients required blood transfusions, researchers noted.

Treatment-related deaths also were higher in the combo group, 14 versus 7, but rates of people dropping treatment were low, researchers said.

“These findings are striking because they support widespread genomic testing at diagnosis with use of a targeted treatment for patients who stand to derive the greatest benefit,” Attard said.

“For cancers with a mutation in one of the eligible HRR genes, where niraparib has been approved, a doctor should consider a discussion that balances the risks of side effects against the clear benefit to delaying disease growth and worsening symptoms,” he added.

More information

The American Cancer Society has more on prostate cancer treatment.

SOURCE: University College London, news release, Oct. 7, 2025

What This Means For You

Men with prostate cancer should ask for a genetic test to see if they might benefit from niraparib treatment.