Xtandi Cardiotoxicity Explained by Vioxx Similarity

Xtandi (Enzalutamide) has been FDA approved but comes with a seizure risk warning on the label. Xtandi has a biarylcyclopentane molecular structure that is very similar to the drug Vioxx which was withdrawn from the market due to cardiotoxic risks. The APPROVE study showed an increased risk of cardiotoxicity with Vioxx compared to a placebo and a similar trial should be conducted on Enzalutamide.

Molecular Structure of Enzalutamide (Xtandi)

Molecular Structure of Rofecoxib (Vioxx)

Rofecoxib is an anti inflammatory agent that works as a selective COX-2 inhibitor. Rofecoxib was approved by the FDA on May 20, 1999, and was marketed under the brand name Vioxx.
Rofecoxib gained widespread acceptance among physicians treating patients with arthritis and other conditions causing chronic or acute pain. Worldwide, over 80 million people were prescribed rofecoxib at some time.
In 2004 Merck withdrew rofecoxib from the market because of concerns about increased risk of heart attack and stroke associated with long-term use. Merck withdrew the drug after disclosures that it withheld information about rofecoxib's risks from doctors and patients for over five years, resulting in between 88,000 and 140,000 cases of serious heart disease. Rofecoxib was one of the most widely used drugs ever to be withdrawn from the market. In the year before withdrawal, Merck had sales revenue of US$2.5 billion from Vioxx. By the time it was discontinued in 2004, it had already caused an estimated 60,000 deaths worldwide.