Analysis validates 22-gene genomic classifier in biochemically recurrent prostate cancer

February 25, 2021
Jason M. Broderick

The outcome of the Decipher Prostate test was independently associated with overall survival, prostate cancer–specific mortality, and risk of metastasis.

Decipher Prostate, a 22-gene microarray-based genomic classifier, was clinically validated as a predictor of overall survival (OS) in men with biochemically recurrent prostate cancer after radical prostatectomy (RP), according to an ancillary study of the pivotal phase 3 NRG/RTOG 9601 trial.1,2

The outcome on the genomic classifier, known as the Decipher Score, was independently associate with OS, prostate cancer–specific mortality, and risk of metastasis.

"Identifying which patients with recurrent disease are most likely to benefit from hormonal therapy will improve our ability to extend patient survival, while minimizing unnecessary toxicity for a large group of men with prostate cancer," lead author Felix Feng, MD, vice chair of radiation oncology at University of California, San Francisco, stated in a press release. "Decipher Prostate RP improves upon clinical and pathological risk stratification methods and informs the use of hormonal therapy, making it a reasonable and recommended component of the prostate cancer standard of care."

The ancillary study used RP specimens obtained in the practice-changing NRG/RTOG 9601 (NCT00002874) randomized clinical trial. These specimens from that phase 3 placebo-controlled study were collected between March 1998 and March 2003. The double-blind NRG/RTOG 9601 study included 760 patients with recurrent pT3N0 prostate cancer after RP and pelvic lymphadenectomy.3 Patients were randomized to receive radiation therapy with either antiandrogen therapy (24 months of daily bicalutamide) or placebo tablets daily during and after radiation therapy. OS was the primary end point.

In NRG/RTOG 9601, the OS rate at 12 years was 76.3% in the bicalutamide arm versus 71.3% in the placebo arm, translating to a 33% reduction in the risk of death (HR, 0.77; P = .04). Prostate cancer–related death at 12 years occurred in 5.8% versus 13.4% of the 2 arms, respectively (P <.001).

For the ancillary study, the researchers used specimens from 352 men randomized to either placebo or hormone therapy in NRG/RTOG 9601. The median age of these men was 64.5 years (range, 60-70) and 89.2% were White. Statistical modeling showed that Decipher was independently associated with distant metastasis (HR, 1.17; P = .006),prostate cancer–specific mortality (HR, 1.39; P <.001), and OS (HR, 1.17; P = .002).

"This is very exciting, as the study validates Decipher Prostate as the first independent predictor of overall survival and shows how predicting metastatic risk with the Decipher test can be utilized to better guide treatment decisions in men with a prostate specific antigen recurrence," Tina S. Nova, PhD, president and chief executive officer of Decipher Biosciences, stated in the press release.

References

1. Decipher Test Clinically Validated as a Predictor of Overall Survival in Men with Prostate Cancer. Published online February 11, 2021. Accessed February 25, 2021. https://prn.to/3pZ3X7X.

2. Feng FY; Huang H-C, Spratt DE, et al. Validation of a 22-gene genomic classifier in patients with recurrent prostate cancer: an ancillary study of the NRG/RTOG 9601 randomized clinical trial [published online ahead of print February 11, 2021]. JAMA Oncol. doi: 10.1001/jamaoncol.2020.7671

3. Shipley WU, Seiferheld W, Lukka HR, et al. Radiation with or without antiandrogen therapy in recurrent prostate cancer. N Engl J Med. 2017 Feb 2;376(5):417-428. doi: 10.1056/NEJMoa1607529