Amid a substantial expansion of therapies in several drug classes for the treatment of osteoporosis, there has been a notable increase in the prescription of denosumab for patients with a cancer-related indication.
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In an analysis of claims data from January 2009 to March 2020, the bisphosphonate alendronate represented more than 50% of all prescriptions for bone-directed therapies, but growth in the use of the monoclonal antibody denosumab overall and in cancer-related indications particularly was steady throughout the study period.
“In the malignancy cohort, alendronate and zoledronic acid were each used in approximately 30% of individuals at the onset of the study, but use of both then declined,” Sara Cromer, MD, reported at the annual meeting of the Endocrine Society.
For malignancy-based prescriptions, denosumab surpassed either bisphosphonate by 2013 and then continued to rise.
Denosumab use “reached approximately 50% of all bone-directed medication use in the malignancy cohort” by the end of the study period, said Dr. Cromer, a clinical research fellow in endocrinology at Massachusetts General Hospital, Boston.
The claims data for this analysis was drawn from the Clinformatics Data Mart. The analysis was restricted to individuals aged older than 50 years who received a prescription for a bone-directed therapy. The 15.48 million prescriptions evaluated were drawn from 1.46 million unique individuals. The mean age was 69 years, and 89% of those prescribed a drug were women.
Oncologic indications one of two tracked cohorts
In the context of a large expansion of treatment options in several drug classes for osteoporosis, the objective of this claims analysis was to document trends in treatment choice, according to Dr. Cromer. She and her coinvestigators looked at prescriptions overall as well as in two cohorts defined by ICD codes. One included patients prescribed a prescription by an oncologist. The other included everyone else.
When all prescriptions for bone-directed therapy were evaluated over the study period, alendronate was the most commonly prescribed therapy, and its use increased over time. Prescriptions of zoledronic acid also rose, doubling over the study period, but use was very low in the beginning and it never climbed above 5%.
The proportion of prescriptions written for bisphosphonates other than alendronate and zoledronic acid “declined steadily” over the study period, Dr. Cromer reported.
Denosumab, a monoclonal antibody that targets a step in the process important to maturation of osteoclasts, was approved in 2010. It accounted for 10% of all prescriptions for osteoporosis by 2015 and 15% by 2018. It was still rising through the end of the study period.
In contrast, prescriptions of raloxifene, a selective estrogen receptor modulator, began to decline after 2013. In general, the rates of prescriptions for other agents, including some of the more recently approved drugs, such as teriparatide, abaloparatide, and romosozumab, changed very little over the study period. None of these therapies ever represented more than 2% of prescriptions.
When looking at the cohort of patients who received a bone-directed reason for a noncancer indication, the trends “paralleled those in the all-user analysis,” Dr. Cromer reported.