In June, the Concord, Mass.–based company Tremeau Pharmaceuticals announced that the Food and Drug Administration was letting it proceed with a phase 3 clinical trial to test rofecoxib, the once-bestselling painkiller known as Vioxx, in patients with migraine.
The anti-inflammatory drug, a cyclooxygenase-2 (COX-2) inhibitor, received its first FDA approval in 1999 and became widely prescribed for arthritis and acute pain. In 2004 it was withdrawn by its manufacturer, Merck, after being shown to raise the risk of cardiovascular events.
In clinical trials and in real-world epidemiological studies, rofecoxib was associated with elevated heart attack, stroke, and related deaths; one 2005 study estimated that it had been responsible for some 38,000 excess deaths in the United States before being withdrawn. In 2007 Merck, beset with allegations that it had suppressed and mischaracterized rofecoxib’s safety data, paid out nearly $5 billion to settle thousands of lawsuits filed by patients and their families.
Shortly before its withdrawal, rofecoxib was approved for the treatment of migraine. Now, with its original patents expired, Tremeau hopes to gain approval for its reformulated version of the drug in both migraine and in hemophilia arthropathy, an indication for which it received an orphan drug designation in 2017 and the agency’s green light for trials in 2020.
Brad Sippy, Tremeau’s chief executive officer, said that his company chose the two indications in part because both patient populations have low cardiovascular risk. Migraine patients are generally younger than the arthritis populations formerly treated with rofecoxib and are unlikely to take the drug for more than a day or 2 at time, avoiding the risks associated with extended exposure.
A Crowded Market
The past several years have seen the emergence of a cornucopia of new migraine treatments, including monoclonal antibodies such as erenumab (Aimovig, Amgen), which help prevent attacks by blocking the vasodilator calcitonin gene-related peptide, or CGRP. In addition to the standard arsenal of triptans and nonsteroidal anti-inflammatory drugs for acute pain relief, migraine patients can now choose among serotonin-blocking agents such as lasmiditan (Reyvow, Eli Lilly), known as “ditans,” and small-molecule CGRP antagonists such as ubrogepant (Ubrelvy, Abbie), known as “gepants.” Some NSAIDs, including one COX inhibitor, have been formulated into rapidly absorbed powders or liquids for migraine.
Mr. Sippy said he sees a role for rofecoxib even in this crowded space. “Migraine as you know is a multimodal situation – few people say that only one drug works for them,” he said. “We think this is an option that would basically be like a high dose of ibuprofen,” but with less frequent dosing and lower gastrointestinal and platelet effects compared with ibuprofen and other NSAIDs.
An Improved Formulation
Rofecoxib “crosses the blood brain barrier very readily – better than other COX inhibitors on the market,” Mr. Sippy added. “It was well absorbed in its original formulation, and our product is even better absorbed than the original – we estimate it’s probably an hour quicker to [peak concentration].” In addition, he said, “our formulation is more efficient at delivering the drug so we don’t need as much active ingredient – our 17.5 milligrams gets you the same systemic exposure as 25 milligrams of the old product.”
A Different Mechanism of Action
Neurologist Alan M. Rapoport, MD, editor-in-chief of Neurology Reviews and professor of neurology at the University of California, Los Angeles, said that he was “cautiously optimistic” that “if used correctly and not too frequently, [rofecoxib] will find its niche in migraine treatment.”
“Patients liked Vioxx,” said Rapoport, past president of the International Headache Society. Even people currently on prevention “need to have an acute care drug handy.” While some patients on monoclonal antibodies have had success with gepants for acute care, “these both target the same pathway. It’s always nice to have options with a different mechanism of action.”
One of the arguments Tremeau has cited for reintroducing rofecoxib has been an urgent need for alternatives to opioid painkillers. Indeed some analysts have linked the demise of Vioxx with a subsequent increase in opioid prescribing.
Rapoport noted that he never prescribes opioids or butalbital, a barbiturate, for migraine, and that most headache specialists avoid them in clinical practice. But in the emergency setting, he said, patients receive them all too frequently.
Mr. Sippy said that opioid prescribing, while not unknown in migraine, was a bigger problem in hemophilic arthropathy, the first indication his company has pursued for rofecoxib. People with hemophilia “have a kind of arthritis that would respond well to an anti-inflammatory drug but they can’t take NSAIDs due to bleeding risk. This is why so many end up on opioids. Rofecoxib, as a COX-2 inhibitor, doesn’t have any effect on platelet aggregation, which would make it another option.”
No Unique Risks at Prescribed Doses
The migraine indication originally started out narrower: Patients with both migraine and bleeding disorders. “But in talking with the FDA, they encouraged us to develop it for migraine,” Mr. Sippy said. The company is considering pursuing a third indication: menstrual pain co-occurring with migraine. Tremeau has not ruled out seeking an indication in patients with arthritis who cannot take other painkillers, whether opioids or NSAIDs.
Five years ago, when Tremeau first announced its plans to bring rofecoxib back – indeed the company was set up for that purpose and has only this and another COX-2 inhibitor in development – some experts warned that there is little to prevent the drug from being used off-label, whether in higher doses or for other diseases.
“That’s something else we’re seeking to solve in addition to going for younger populations,” said Mr. Sippy, who worked at Merck during the Vioxx crisis and later headed neurology at Sunovion before starting his own company.
“We’re going for the former middle dose as our high dose and now we know that you don’t want to take more than the prescribed amount. If it doesn’t work you get off it; you don’t want to dose-creep on it. That’s been a key insight: At the appropriate dose, this product has no unique risk relative to the drug class and potentially some unique benefits,” he said.
Risk Versus Benefit
Joseph Ross, MD, a health policy researcher at Yale University in New Haven, Conn., who in a 2018 editorial expressed concerns about rofecoxib’s revival, said in an email that he felt its use in migraine could be justified, with caveats.
During Vioxx’s original approval and time on the market, “there was a cardiovascular risk associated with use that was not being transparently and clearly reported to patients and clinicians,” Ross said.
“In terms of testing the product for use in patients with migraine – a population of generally younger patients at lower risk of cardiovascular disease – my only concern is that the risk is clearly communicated and that there is adequate postmarket safety surveillance,” he said. “If patients are making fully informed decisions, the potential benefit of the drug with respect to pain control may be worth the risks.”
Rapoport serves as an adviser for AbbVie, Amgen, Biohaven, Cala Health, Collegium Pharmaceutical, Satsuma, Teva, Theranica and Xoc; he is on the speakers bureau of AbbVie, Amgen, Biohaven, Impel, Lundbeck, and Teva. Ross disclosed research support from Johnson and Johnson, the Medical Device Innovation Consortium, and the Laura and John Arnold Foundation, along with government grants; he is also an expert witness in a lawsuit against Biogen.
This story originally appeared on MDedge.com, part of the Medscape Professional Network.
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