A new drug combination offers reason for optimism for men facing advanced prostate cancer, especially those with genetic mutations making their cells less able to fight the disease.

Pairing a targeted therapy called niraparib with standard hormone treatment for prostate cancer can significantly delay the progression of the disease and improve a man's quality of life, a major international study has found.

What makes the research especially exciting is that all the participants were particularly tough cases.

The findings come from the University College London's Cancer Institute's Phase III Amplitude trial. The study enrolled 696 men from 32 countries, all diagnosed with metastatic prostate cancer that had spread beyond the prostate and who had not yet received treatment.

The men were, on average, 68 years old. Half were randomly assigned to receive the new combination therapy, niraparib plus the standard drugs abiraterone acetate and prednisone (known as AAP). The other half received AAP plus a placebo.

What makes the research especially exciting is that all the participants had a genetic disadvantage that made them tough cases. Each of the men had changes in the genes known to reduce DNA repair. These genes — BRCA1, BRCA2, CHEK2, and PALB2 — help fix genetic damage that occurs naturally as cells divide.

When these genes are faulty, cancer cells can grow and spread faster. Roughly one in four men with advanced prostate cancer have these genetic alterations, which also tend to make their disease more aggressive and less responsive to traditional treatments.

Standard care for advanced prostate cancer typically involves hormone-blocking therapy, sometimes alongside chemotherapy. But for men with BRCA gene mutations, cancer progression often comes sooner, and life expectancy is shorter.

That's what makes the results so noteworthy.

After a follow-up at 30.8 months, researchers found that adding niraparib reduced the risk of cancer growth by 37 percent compared with AAP alone.

For men with BRCA1 or BRCA2 mutations the benefits were even more striking — a 48 percent reduction in the risk of progression. In practical terms, the time until symptoms worsened was twice as long in the niraparib group compared with those receiving only the standard therapy. The proportion of men experiencing significant symptom worsening dropped from 34 percent to 16 percent.

“The 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,” lead author Gerhardt Attard, Chair of Medical Oncology at University College London's cancer institute, said in a news release.

“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. By combining with niraparib we can delay the cancer returning and hopefully significantly prolong life expectancy," Attard commented.

Adding niraparib reduced the risk of cancer growth by 37 percent.

While promising, the treatment isn't without side effects. The niraparib group reported higher rates of anemia and high blood pressure, and about one in four required blood transfusions. There were also 14 treatment-related deaths in the niraparib group compared with seven in the placebo group, although discontinuation rates remained low.

Researchers emphasized that these risks must be weighed carefully against the significant delay in disease progression and the worsening of symptoms. Still, the overall message is one of progress. Even though a longer follow-up is needed to confirm whether niraparib ultimately extends survival, early signs point in that direction.

The study team also noted that this research strengthens the case for routine genomic testing for all men diagnosed with prostate cancer to identify those most likely to benefit from targeted therapies. For men facing life-threatening cancer, the new drug therapy offers a promising treatment option.

Published in Nature Medicine.