Access to Migraine Treatments in Ontario, Canada: A Review of the Ontario Drug Benefit Program

Long-Term Effectiveness of Three Anti-CGRP Monoclonal Antibodies in Resistant Chronic Migraine Patients Based on the MIDAS score

BACKGROUND

Criteria, including clinical features and effective outcomes, for access and persistence of novel but costly treatments may vary between countries, thus affecting the health of patients. Monoclonal antibodies against the calcitonin gene-related peptide pathway (anti-CGRP mAbs) for migraine treatment are currently prescribed following strict criteria.

OBJECTIVE

The aim was to assess the effectiveness and safety of three anti-CGRP mAbs (erenumab, galcanezumab, and fremanezumab) in consecutive resistant chronic migraine patients presenting at our Headache Center and the impact of criteria set by the Italian Medicines Agency to start and continue (achieving a ≥ 50% reduction in Migraine Disability Assessment [MIDAS] score) with treatment under the reimbursement program.

METHODS

A monocentric, prospective, cohort study was conducted, enrolling 203 severe (resistant to three or more preventive treatments) chronic migraine patients (84.7% with medication overuse) treated with erenumab (47.2%), galcanezumab (36.5%), or fremanezumab (16.3%), with up to 12 months follow-up. Patients completed a headache diary that included monthly migraine days (MMDs), number of analgesics and days with analgesic use, and patient-reported outcome questionnaires (MIDAS, Headache Impact Test 6 [HIT-6] questionnaires, and the Patient Global Impression of Change [PGIC] scale). Moreover, percentages of patients showing ≥ 50%, ≥ 75% and 100% reduction in MMDs (responder rates) were calculated at different follow-ups. A subgroup analysis was performed for patients with 12-month follow-up. Potential predictors of response were assessed at different follow-ups.

RESULTS

In the overall population, all three anti-CGRP mAbs were similarly effective and dropouts were 17.2%. The percentage of patients with ≥ 50% reduction in MMDs (min-max 36.4-56.8%) and in monthly analgesic consumption (51.1-75.7%) was inferior to the percentage of patients who reported a ≥ 50% reduction in MIDAS score (89.5-100%). HIT-6 score was also consistently reduced at all follow-ups. In patients with a 12-month follow-up, MIDAS and HIT-6 scores were also reduced at all follow-ups compared with baseline, with 84.4-100% of patients achieving a ≥ 50% reduction in MIDAS score, and patients with a ≥ 50% response rate ranging from 36.4 to 66.6%. No severe adverse events were recorded. Fewer migraine days at baseline were associated with ≥ 50% response rate at 1 month and fewer MMDs, years of chronic migraine, and monthly analgesic use at 6 months.

CONCLUSION

In resistant chronic migraine patients, anti-CGRP mAbs are effective and safe. A ≥ 50% reduction in MIDAS score seems to be the most advantageous outcome measure in this setting, which allows most severe migraine patients to persist with treatment.

Predictors of Sustained Response and Effects of Anti-CGRP Antibodies Discontinuation and Reinitiation in Resistant Chronic Migraine

BACKGROUND

Guidelines for migraine prophylaxis suggest stopping medication after 6-12 months to reevaluate treatment appropriateness. The Italian Medicines Agency (AIFA) set a mandatory regulation to stop anti-CGRP (calcitonin gene related protein) pathway monoclonal antibody (anti-CGRP mAbs) treatments for 3 months after 12-months of treatment. Herein, we assess the effects of discontinuation and retreatment of anti-CGRP mAbs in resistant chronic migraine patients, evaluating predictive factors of sustained response.

METHODS

A monocentric prospective cohort study, enrolling 44 severe (resistant to ≥3 preventive treatments) chronic migraine patients (all with medication-overuse), treated with erenumab (54.5%) or galcanezumab (45.5%) for 12-months, who discontinued treatment for three months and then restarted for one month.

RESULTS

Overall, patients reported an increasing deteriorating trend during the three months of discontinuation. Monthly migraine days (MMDs), number of analgesics, days with at least one analgesic used, a ≥50% response rate (reduction in MMDs), and MIDAS and HIT-6 total scores, remained lower than baseline values, but increased if compared to month-12 of treatment. All outcome measures decreased again during the month of retreatment. Patients who did not meet criteria for restarting treatment had lower MIDAS (p=0.03) and HIT-6 (p=0.01) scores at baseline and better outcome measures during discontinuation compared to patients who restarted treatment.

CONCLUSIONS

In most patients, the 3-month discontinuation of anti-CGRP mAbs resulted in progressive migraine deterioration that was rapidly reverted by retreatment. However, one-fourth of patients, who reported better quality of life indices before treatment, showed a sustained benefit during discontinuation and did not need retreatment.

Botulinum Toxin in the Treatment of Headache

Botulinum toxin type A has been used in the treatment of chronic migraine for over a decade and has become established as a well-tolerated option for the preventive therapy of chronic migraine. Ongoing research is gradually shedding light on its mechanism of action in migraine prevention. Given that its mechanism of action is quite different from that of the new monoclonal antibodies directed against calcitonin gene-related peptide (CGRP) or its receptor, it is unlikely to be displaced to any major extent by them. Both will likely remain as important tools for patients with chronic migraine and the clinicians assisting them. New types of botulinum toxin selective for sensory pain neurons may well be discovered or produced by recombinant DNA techniques in the coming decade, and this may greatly enhance its therapeutic usefulness. This review summarizes the evolution of botulinum toxin use in headache management over the past several decades and its role in the preventive treatment of chronic migraine and other headache disorders.