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Discontinuation Patterns Provide Support for Long-Term Effectiveness of Erenumab
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Over half of the patients (56.7%) discontinued at least one class of acute migraine medication within 12 months post-erenumab initiation.
In a claims database study of more than 200,000 adults with migraine, investigators observed a higher rate of discontinuing acute and preventive migraine medications in the 12-month period after erenumab (Aimovig; Amgen) initiation, as compared with the 6-month follow-up period. Overall, these data could reflect the possible longer-term therapeutic benefit demonstrated with erenumab as well as treatment modifications by prescribers.1
Published in Headache, the real-world retrospective study included 201,176 patients from the IQVIA open-source longitudinal prescription (LRx) and medical (Dx) claims databases. The index window of the study was from May 2018 to through April 2020 to account for a 12-month pre-index period and a minimum 12-month follow-up period with the date of initial prescription of erenumab assigned as the index date.
The study, led by Robert Urman, PhD, an observational research senior manager at Amgen, comprised of mostly females (85.6%), with a mean cohort age of 47.5 years at first erenumab claim. Coming into the study, most patients (88.4%) used at least 1 acute migraine medication during the 12-month pre-index period (triptans: 59.4%; non-triptans: 73.3%; NSAIDs: 44.1%; non-NSAIDs/non-opioid analgesics: 25.1%). Similarly, most patients (86.1%) used at least 1 class of migraine preventive medication during the pre-index period (anticonvulsants: 58.0%; antidepressants: 56.5%; antihypertensives: 38.2%; bolulinum toxin: 13.4%).
Overall, discontinuation of erenumab was observed in 70.0% (n = 140,809) of total patients; however, this number dropped to 45.3% (n = 91,089) after accounting for patients who restarted erenumab (24.7%; n = 49,720). Among the overall study population, 13.1% (n = 26,446) of patients switched to a different anti-calcitonin gene-related peptide (CGRP) pathway monoclonal antibody and 5.5% (n = 11,046) of patients added another anti-CGRP pathway monoclonal antibody.
This research expanded on a prior study by extending the period of observation for medication use from 6 months to 12 months before and after initiation of erenumab. Compared with the previous study, the overall proportions of patients who discontinued 1 or more acute medication class and preventive medication class were higher pre- and post-index in this 12-month study (acute: 56.7% vs 48.7% at 6 months; 46.7% vs 36.2% at 6 months).2
In the new study, the mean PDC during the 12-month post-index was 0.60 (SD, 0.34) with 40.2% of patients remaining adherent to erenumab (PDC ≥0.80). Among the 153,788 patients with pre- and post-index acute migraine medication use, 56.7% discontinued at least one class of acute medication by the end of the 12-month post-index period including discontinuation of triptans (40.5%), NSAIDs (55.4%), opioids/opioid combinations (37.5%), and non-NSAID/non-opioid analgesics (45.0%).Among the 117,274 patients with pre- and post-index preventive medication use, 46.7% discontinued at least one class of preventive medication during the 12-month post-index period including discontinuation of anticonvulsants (38.6%), antidepressants (31.3%), and antihypertensives (35.0%).
In terms of treatment patterns, the index erenumab prescription dose was 70 mg for most patients (65.4%) with the remainder of patients having an index prescription for a single 140 mg dose (14.8%) or 2 x 70 mg syringes (19.7%). Among patients who started on 70 mg, 30.6% had their dose increased to 140 mg after a median of 128 days, while 12.1% of those who started at 140 mg had their dose decreased to 70 mg after a median of 99 days.
"The main strengths of our study include the relatively large sample size of patients initiating preventive treatment for migraine with erenumab and the pre–post design," the study authors wrote.1 "Unlike other prior retrospective studies evaluating patients initiating erenumab, this study used open-source claims data instead of adjudicated insurance claims data, which enabled identification of patients initiating erenumab across all payer types, including those using discounts/coupons to assist with access to erenumab, commercial insurance, Medicare, and Medicaid."
Urman et al added, "The use of the open-source claims adds strength to the analysis by increasing the likelihood that index erenumab claims were accurately classified as the patients’ first erenumab claim and by allowing for the identification of a large, geographically dispersed sample of patients."
