Australia's Drug Regulator Issues Warnings And Mandates Label Changes, Following Similar Action In Europe; Will FDA Follow Thess Leads?
In early August 2016 we learned about some new apparent side effects of Prolia as well as Xgeva, QT interval prolongation and severe symptomatic hypocalcemia.
Denosumab is the active ingredient for Prolia and Xgeva, both of which are made by biotech pharmaceutical company Amgen Inc. Prolia is a treatment for osteoporosis and osteopenia. Xgeva is a drug used for the prevention of skeletal-related events in adults with bone metastases from solid tumors.
This emerging drug safety issue was recently addressed by Australia’s Therapeutic Goods Administration (TGA), and was initially identified by that drug regulator during an assessment of adverse event reports relating to Prolia and Xgeva.
From this August 12, 2016 article, "Australia’s TGA issues warning on denosumab and QT prolongation", published on the ThePharmaLetter (subscription required) website, we get this detailed information:
Product information update
Hypocalcemia is a known effect of denosumab and was already captured in the Product Information (link is external) (PI). However, there was previously no reference to QT prolongation, which is a potentially life-threatening disorder, or to severe symptomatic hypocalcemia.
The following sections of the PI have been updated:
- in the post-marketing setting, severe symptomatic hypocalcemia has been reported, with most cases occurring in the first weeks of initiating therapy (although it can occur later);
- routine clinical monitoring of calcium levels is recommended; and
- information about the symptoms of hypocalcemia and the importance of maintaining calcium levels should be given to all patients being treated with denosumab.
- Adverse Effects
- examples of the clinical manifestations of severe symptomatic hypocalcemia have included QT interval prolongation, tetany, seizures and altered mental status; and
- symptoms of hypocalcemia in denosumab clinical studies included paresthesias or muscle stiffness, twitching, spasms and muscle cramps.
This updated information has harmonized the Australian PIs with the European Union Summary of Product Characteristics for these products.
We will watch for further developments concerning these emerging drug safety issues with Prolia and Xgeva, such as any similar regulatory action by the FDA here in the US.
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