PHILADELPHIA – Atogepant, an oral small-molecule migraine drug from the “gepant” class, showed safety and efficacy for preventing migraine headaches in a phase 2/3, dose-ranging trial with 825 evaluable patients.
Atogepant is the first drug from this novel class to undergo efficacy testing in an advanced-phase trial for prevention of migraine headaches,, said at the annual meeting of the American Headache Society. Two other agents from the gepant class, and , have undergone phase 3 testing for acute treatment of migraine headache, and both drugs are now under Food and Drug Administration consideration for an acute-treatment indication.
Three monoclonal antibodies to the calcitonin gene–related peptide (CGRP) receptor have received FDA marketingsince 2018 for migraine headache prevention. The small-molecule antagonists to the CGRP receptor in the gepant class have an effect similar to the monoclonal antibodies, but with different dosage schedules, an oral route of administration, and with half-lives measured in hours, compared with days and weeks.
“Historically the [gepant] class of drugs was designed for acute treatment, and a couple of drugs from this class didn’t make it because of liver toxicity, but the liver toxicity is not a class effect.” The more recent candidate agents – atogepant, ubrogepant, and rimegepant – have shown hepatic safety as well as overall safety, noted Dr. Dodick, a neurologist and headache specialist at the Mayo Clinic in Phoenix.
If these gepant agents eventually receive FDA approval, which seems likely based on the evidence collected so far, they would collectively form “the only class to have both acute and preventive indications” for migraine, Dr. Dodick said in an interview. The preventive efficacy seen with atogepant in the current study is likely a class effect that has not yet been tested in ubrogepant and rimegepant.
In the multicenter
The researchers had safety data for 825 patients, and efficacy data for 795.
The study’s primary efficacy endpoint was the reduction from baseline in average migraine headache days per month after 12 weeks on treatment. Average migraine headache days fell by 2.85 days in the placebo group and by 3.55-4.23 days in the atogepant treatment groups, a significant difference. The reduction depended on the dosage patients received, but there was no clear dose-response relationship.
At least a 50% drop in average monthly headache day totals was seen in 40% of the placebo patients and in 52%-62% of the patients on atogepant, depending on their dosage. In this case, a signal appeared for a dose-response relationship as only the two subgroups with the patients who received the largest atogepant dosages showed statistically significant improvements in response, compared with placebo.
All patients on atogepant, regardless of their dosage, also had statistically significant reductions in their use of acute migraine medications, compared with placebo patients.
The level of benefit beyond placebo seen in these results was “clinically meaningful,” and roughly comparable with the preventive benefit seen with both the CGRP receptor antagonist monoclonal antibodies, as well as with the three conventional agents most commonly used for migraine headache prevention in current U.S. practice: topiramate, amitriptyline, and propranolol, Dr. Dodick said. Amitriptyline is not approved for this indication.
The adverse event profile among patients who received atogepant was about the same as it was among the placebo recipients. Seven study patients had serious treatment-related adverse effects; two of these patients were in the placebo arm of 186 patients. The most common adverse events were nausea, constipation, and fatigue, and were seen mostly at the highest dosage of atogepant. The incidence of elevated liver enzymes was low and similar in the placebo and drug-treated patients. Two patients, one on placebo and one on atogepant, had their liver enzymes reach at least five times the upper limit of normal. None had their enzymes reach at least 10 times the upper limit of normal, and no patients in the study had a response that fulfilled “,” which flags drug-induced liver injury as patients who develop the combination of elevated liver enzymes, elevated bilirubin, and depressed alkaline phosphatase.
The study was sponsored by Allergan, the company developing atogepant and ubrogepant. Dr. Dodick has been a consultant to Allergan and to several other drug companies.