“When you have targeted preventive treatment and you reduce the burden of illness, medication overuse seems to be reduced as well,” said, adjunct clinical associate professor of anesthesiology and perioperative and pain medicine at Stanford (Calif.) Health Care. Dr. Aurora also is a medical fellow and global launch leader for galcanezumab at Eli Lilly, which has developed the treatment.
Galcanezumab is a humanized monoclonal antibody that selectively binds to the calcitonin gene-related peptide. The phase 3 EVOLVE-1, EVOLVE-2, and REGAIN studies indicated galcanezumab’s superiority to placebo in preventing episodic and chronic migraine.
A post hoc analysis of phase 3 data
Dr. Aurora and colleagues conducted a post hoc analysis of data from the three phase 3 studies to examine galcanezumab’s effect in patients with medication overuse. EVOLVE-1 and EVOLVE-2 included patients with episodic migraine, and REGAIN included patients with chronic migraine. All participants were randomized to monthly subcutaneous injections of placebo or galcanezumab (120 mg/month or 240 mg/month) for 3-6 months. Based on information obtained through electronic patient-reported outcome diaries, investigators determined headache medication overuse using criteria adapted from the International Classification of Headache Disorders, third edition. They estimated mean changes in monthly headache days and the proportion of patients with medication overuse after randomization using mixed modeling.
The demographic characteristics of the three study populations were similar to those reported in epidemiologic studies of migraine, said Dr. Aurora. Most participants were women, and most patients were between ages 40 and 49 years. At baseline, the mean number of monthly migraine headache days was 20 among patients with chronic migraine and 9 among patients with episodic migraine.
The rate of medication overuse was higher in the combined study population than in the literature. Patients with medication overuse had greater disability and greater health care resource utilization, compared with patients without medication overuse. Among patients with chronic migraine, participants who overused medication were not significantly different from those who did not. But among patients with episodic migraine, participants who overused medication had higher headache frequency than those who did not.
In the EVOLVE trials, the proportion of patients with baseline medication overuse was 19.3% in the placebo arm, 17.0% in the galcanezumab 120-mg arm, and 19.2% in the galcanezumab 240-mg arm. In REGAIN, the proportion of patients with baseline medication overuse was 63.4% in the placebo arm, 64.3% in the galcanezumab 120-mg arm, and 64.1% in the galcanezumab 240-mg arm.