Newly diagnosed men with high-risk metastatic hormone-naive prostate cancer (mHNPC) lived significantly healthier, longer lives when doctors added Zytiga (abiraterone acetate) and prednisone to their androgen deprivation therapy (ADT), according to results from the Phase 3 LATITUDE trial.

The trial (NCT01715285), designed by Belgian pharmaceutical giant Janssen, assessed the safety and effectiveness of the triple combination compared to that of ADT alone. Zytiga is an inhibitor of androgen production of the testes, adrenal glands and the tumor itself, while prednisone is an immunosuppressant.

“In the LATITUDE trial, we found that abiraterone acetate plus prednisone, in combination with androgen deprivation therapy, demonstrated statistically significant and clinically meaningful improvements in patients with high-risk metastatic hormone-naive prostate cancer,” Dr. Karim Fizazi, principal investigator of the trial, said in a press release.

Janssen conducted the study at 235 sites in Canada and 33 European, Asian and Latin American countries.  Of the 1,199 men enrolled, 597 were randomly selected to receive ADT in combination with Zytiga plus prednisone, and 602 received ADT and placebo, in a double-blind manner—neither patients nor doctors knew which patient was receiving which treatment.

The trial primary goals were to determine patients’ overall survival and time to disease progression or death, assessed by spread in radiographic scans.

Participants receiving the triple combo showed a 38 percent lower risk of death and a 53 percent lower risk of disease progression (assessed by metastases spread in radiographic scans). It took a median 33 months before the disease progressed in men on the triple combo, compared to a median 14.8 months for those on placebo.

The combined treatment also improved all secondary measures, such as the time it took for pain to progress. It also delayed the initiation of chemotherapy or the next subsequent form of therapy, and postponed progression of PSA blood levels and of bone metastases. Its most common side effects were higher blood pressure and lower potassium levels in the blood.

“This is important new information, as not all patients respond well to the current standard of care,” Fizazi said. “LATITUDE suggests that abiraterone acetate plus prednisone, in combination with androgen deprivation therapy, can offer a new and much-needed option for patients with high-risk newly diagnosed mHNPC.”