Rofecoxib

Rofecoxib is a COX-2 selective nonsteroidal anti-inflammatory drug (NSAID). It was marketed by Merck & Co. to treat osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, acute pain conditions, migraine, and dysmenorrhea. Rofecoxib was approved in the US by the US Food and Drug Administration (FDA) in May 1999, and was marketed under the brand names Vioxx, Ceoxx, and Ceeoxx. Rofecoxib was available by prescription in both tablet-form and as an oral suspension. Rofecoxib is a COX-2 selective nonsteroidal anti-inflammatory drug (NSAID). It was marketed by Merck & Co. to treat osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, acute pain conditions, migraine, and dysmenorrhea. Rofecoxib was approved in the US by the US Food and Drug Administration (FDA) in May 1999, and was marketed under the brand names Vioxx, Ceoxx, and Ceeoxx. Rofecoxib was available by prescription in both tablet-form and as an oral suspension. 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 September 2004, Merck voluntarily withdrew rofecoxib from the market because of concerns about increased risk of heart attack and stroke associated with long-term, high-dosage use. Merck withdrew the drug after disclosures that it withheld information about rofecoxib's risks from doctors and patients for over five years, allegedly 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 Rofecoxib was one of the most widely used drugs ever to be withdrawn from the market.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. In 2005 the FDA issued a memo concluding that data from large long-term controlled clinical trials do not clearly demonstrate that COX-2 selective agents (including rofecoxib) have a greater risk of serious CV events than non-selective NSAIDs. The FDA reinforced this position in 2015, stating that the available data support a dose and duration dependent class effect of an increased risk of serious adverse cardiovascular events for COX-2 selective and non-selective NSAIDs. In November 2017, Massachusetts-based Tremeau Pharmaceuticals announced its plan to return rofecoxib (TRM-201) to market as a treatment for hemophilic arthropathy (HA). Tremeau announced that the FDA had granted an orphan designation for TRM-201 (rofecoxib) for the treatment of HA, and that they had received FDA feedback on their development plan. HA is a degenerative joint disease caused by recurrent intra-articular bleeding. It is the largest cause of morbidity in patients with hemophilia and has no currently approved treatment options in the United States. Traditional NSAIDs are avoided in this population due to their effects on platelet aggregation and risk of gastrointestinal ulcers, and high potency opioids are the current standard of care in treating HA. Cyclooxygenase (COX) has two well-studied isoforms, called COX-1 and COX-2. COX-1 mediates the synthesis of prostaglandins responsible for protection of the stomach lining, while COX-2 mediates the synthesis of prostaglandins responsible for pain and inflammation. By creating 'selective' NSAIDs that inhibit COX-2, but not COX-1, the same pain relief as traditional NSAIDs is offered, but with greatly reduced risk of fatal or debilitating peptic ulcers. Rofecoxib is a selective COX-2 inhibitor, or 'coxib'. Though the class of coxibs includes several agents, there are varying degrees of COX-2 selectivity among them, with celecoxib (Celebrex) being the least COX-2 selective, and rofecoxib (Vioxx), valdecoxib (Bextra), and etoricoxib (Arcoxia), being highly COX-2 selective. At the time of its withdrawal, rofecoxib was the only coxib approved in the United States with clinical evidence of its superior gastrointestinal adverse effect profile over conventional NSAIDs. This was largely based on the VIGOR (Vioxx GI Outcomes Research) study, which compared the efficacy and adverse effect profiles of rofecoxib and naproxen. The therapeutic recommended dosages were 12.5, 25, and 50 mg with an approximate bioavailability of 93%. Rofecoxib crossed the placenta and blood–brain barrier, and took 1–3 hours to reach peak plasma concentration with an effective half-life (based on steady-state levels) of approximately 17 hours. The metabolic products are cis-dihydro and trans-dihydro derivatives of rofecoxib which are primarily excreted through urine.