Bone-modifying agents — most notably denosumab — are often prescribed to prevent skeletal-related complications in patients with metastatic castration-sensitive prostate cancer, but the drugs are not recommended for this indication and can lead to severe toxicities.
How much does Medicare spend each year on non-recommended bone therapy?
The answer, according to a new analysis in JCO Oncology Practice, is more than $44 million, with about $43 million coming from denosumab alone.
Overall, this study found that “the Medicare program pays tens of millions of dollars each year” for bone-modifying agents in patients with metastatic castration-sensitive prostate cancer, “which is not effective and may cause side effects,” lead author Aaron Mitchell, MD, MPH, a medical oncologist at Memorial Sloan Kettering Cancer Center, New York City, and colleagues concluded.
“These findings suggest reducing bone agent overuse could be a rare healthcare ‘win-win.’ Lower costs AND improved patient outcomes,” tweeted Dr. Mitchell. “If I were a payer, I’d be paying attention!”
In Prostate Cancer, Bone-Modifying Drug Indications Vary
Bone-modifying drugs are indicated for some patients with prostate cancer.
The American Society of Clinical Oncology has endorsed guidelines that recommend the use of denosumab in men with nonmetastatic prostate cancer at high risk for fracture while taking androgen deprivation therapy.
Among men with metastatic castration-resistant prostate cancer, guidelines also recommend zoledronic acid or denosumab for preventing or delaying skeletal-related events, such as pathologic fractures and spinal cord compression.
For patients with metastatic castration-sensitive disease, however, the bone-modifying agents show no benefit in preventing skeletal-related events and are not recommended for that indication.
In this population, “treatment with bone agents results only in avoidable toxicity and financial cost,” Dr. Mitchell tweeted. In its higher-dose formulation, denosumab comes with a price tag of approximately $40,000 per year in the United States.
An earlier study from Dr. Mitchell and colleagues revealed that the use of bone-modifying drugs to prevent skeletal events in metastatic castration-sensitive prostate cancer is common.
To better understand the costs associated with this inappropriate use, the researchers reviewed Surveillance, Epidemiology, and End Results Program Medicare data from 2011 to 2015. The team identified the frequency and number of doses of zoledronic acid and denosumab prescribed against recommendations in the metastatic castration-sensitive setting, making sure to distinguish between the use of denosumab to prevent osteoporotic fractures (appropriate use) and to prevent skeletal-related events (non-recommended use).
The team found that, among 2627 patients with metastatic castration-sensitive prostate cancer, 42% received at least one dose of denosumab and 18% received at least one dose of zoledronic acid.
The authors also found that unnecessary use of these drugs increased over time — with a little over 17% of patients receiving zoledronic acid between 2007 and 2009 and just over 28% receiving either denosumab (20.3%) or zoledronic acid (8.4%) from 2012 to 2015.
The annual costs to Medicare from non-recommended prescribing came to $44,105,041 for both agents, with the costs associated with denosumab representing the lion’s share at $43,303,078.
Non-recommended use of these agents also came with adverse events, such as femur fracture and hypocalcemia, which cost an estimated $758,450 to treat annually — $682,865 for denosumab and $75,585 for zoledronic acid.
The study focused on the Medicare-age population, which means the estimates are conservative. “Denosumab overuse for younger patients with castration-sensitive prostate cancer would add substantially to this total,” the authors wrote.
“This study contributes new evidence of overuse in the metastatic castrate-sensitive prostate cancer setting, which I must admit reflects my clinical experience in seeing patients for second opinions who are treated in the community,” said Samuel U. Takvorian, MD, of the Division of Hematology and Oncology, Perelman School of Medicine, Philadelphia, who wasn’t involved in the research. “While there are some circumstances in which one would consider using a bone-modifying agent in the metastatic castrate-sensitive prostate cancer setting, most [of these] men don’t need them upfront.”