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Treatment dynamics of bone‐targeting agents among men with bone metastases from prostate cancer in the United States
Author(s) -
Butler Anne M.,
Cetin Karynsa,
Hernandez Rohini K.,
Diane Reams B.,
Overman Robert A.,
I. Kim Jung,
Hirsch Bradford R.,
Abernethy Amy P.,
Liede Alexander,
Alan Brookhart M.
Publication year - 2018
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.4360
Subject(s) - medicine , denosumab , zoledronic acid , prostate cancer , bone metastasis , cumulative incidence , androgen deprivation therapy , incidence (geometry) , oncology , cancer , metastasis , prostate , urology , osteoporosis , cohort , physics , optics
Purpose To examine the dynamics of treatment with 2 bone‐targeting agents (BTAs)—denosumab and zoledronic acid—among men with bone metastases from prostate cancer. Methods Using electronic health record data from oncology practices across the US, we identified prostate cancer patients diagnosed with bone metastasis in 2012/2013 without evidence of BTA use within 6 months prior to diagnosis. We examined the risk and predictors of BTA initiation, interruption, and re‐initiation. Results Among 897 men diagnosed with prostate cancer, the cumulative incidence of BTA initiation after bone metastasis diagnosis was 34% (95% confidence interval [CI], 31–37%) at 30 days, 64% (95% CI, 61–68%) at 180 days, and 88% (95% CI, 85–91%) at 2 years. Denosumab was initiated more frequently than zoledronic acid. Men with diabetes, more bone lesions, history of androgen deprivation therapy, or no hospice enrollment were more likely to initiate treatment. Following initiation, the cumulative incidence of treatment interruption was 17% (95% CI, 14–19%) at 60 days and 70% (95% CI, 66–74%) at 2 years, with interruption more likely among patients receiving emerging therapies for prostate cancer or enrolling in hospice. The cumulative incidence of re‐initiation following interruption was 36.3% (95% CI, 32.7–40.2%) at 15 days, 49.8% (95% CI, 45.9–54.1%) at 30 days, and 81.0% (95% CI, 77.5–84.7%) at 1 year. Conclusions Bone‐targeting agent therapy is initiated by the majority of men living with bone metastases following a prostate cancer diagnosis; however, the timing of initiation is highly variable. Once on treatment, gaps or interruptions in therapy are common.