Should the denosumab metastasis prevention trial change practice for men with nonmetastatic prostate cancer?
Authors: Saylor PJ, Michaelson MD
Presentation of the case. A 68-year-old man presents for management of prostate-specific antigen (PSA)-recurrent prostate cancer. His PSA level had become undetectable after prostatectomy for a high-risk localized tumor but began to rise 8 months later. This later led to the initiation of androgen deprivation therapy (ADT), which he has received for the last 3.5 years. After initially falling in response to ADT, his PSA level again trended steadily upward and is now 13.2. Restaging with an abdominal and pelvic computed tomography scan and a bone scan reveals no evidence of metastases. Is this man likely to benefit from denosumab? Bone is the most common site of metastasis for advanced prostate cancer. Bone metastases can cause considerable morbidity in the form of pain, pathologic fractures, and even spinal cord compression. Two bone-targeted therapies (zoledronic acid and denosumab) have been shown to reduce the risk for skeletal events (SREs) among men with bone metastases and a rising PSA level despite a testosterone level <50 ng/dL (castration-resistant prostate cancer [CRPC]). Until recently, no therapy had been shown to reduce the risk for developing bone metastases for the first time. Denosumab 147 was a randomized, placebo-controlled, phase III trial that enrolled 1,432 men with CRPC, no bone metastases, and at least one feature consistent with a high risk for the development of bone metastases (PSA ≥8 ng/mL or PSA doubling time ≤10 months). Participants were treated every 4 weeks with s.c. denosumab (120 mg) or placebo. The trial was positive because denosumab led to a 4.2-month significantly longer bone-metastasis-free survival time relative to placebo (median, 29.5 months versus 25.2 months; hazard ratio [HR], 0.85; 95% confidence interval [CI], 0.73-0.98; p = .028) . The time to first bone metastasis and risk for symptomatic bone metastasis were also significantly better with denosumab treatment. Dror Michaelson and Philip Saylor discuss the potential implications of this trial.
PMID: 22267850 [PubMed – indexed for MEDLINE]