OnabotulinumtoxinA Proves Safe as Migraine Treatment for Pregnant Women

Jacqueline E. Summers, MD

Research from a retrospective review presented virtually at the 2020 American Headache Society (AHS) Annual Meeting demonstrated that treatment with onabotulinumtoxinA (Botox; Allergan) is safe and tolerable in pregnant women with chronic migraine.

Among a cohort of 9 subjects who received onabotulinumtoxinA injections for migraine during pregnancy, none of the 10 pregnancies reported any organ malformations at delivery. Additionally, 1 subject reported that her baby had “low height,” but no other physical, intellectual, or social disabilities were reported and all babies were appropriately met their developmental milestones.

Presented by Jacqueline E. Summers, MD, resident physician, Stanford Univeristy Medical center, the study noted that given the high prevalence of migraine in women of childbearing age, continued evaluation of the safety of available treatments for migraine in pregnancy is prudent.

READ MORE: Erenumab Shows Sustainable Efficacy in Refractory Episodic Migraine

The study included 10 pregnancies, with 1 subject receiving the treatment during 2 separate pregnancies. Overall, 22 treatments were administered throughout the 10 pregnancies, with 8 during the first trimester, 8 in the second trimester, and 6 in the third trimester. Patients received doses ranging from 155 to 185 units, with 155 units being the most frequently administered dosage.

Previous studies had not delved into the safety of onabotulinumtoxinA for the treatment of chronic migraine during pregnancy, only doing so in animal models. Summers and colleagues identified and contacted patients to complete a phone interview on the specific details of their pregnancy, delivery, and newborn health development to fully understand the effects of the therapy.

At the time interviews were conducted, the subjects’ babies ranged from between 2 weeks and 29 months of age. Researchers kept a chart review to determine the dosage and timing of onabotulinumtoxinA administration during pregnancy. The 10 women in the study ranged between 30 to 42 years of age at the time of their pregnancy. The original prompting of the study was rooted in experiences within clinicians’ practice, where the treatment had been shown to improve migraine frequency at pre-pregnancy but had not been observed fully as a continued treatment during pregnancy.

Summers and colleagues, when discussing the background of the study, wrote “In our practice, women with migraine who are considering conception have a dedicated visit to discuss plans for treatment of migraine in pregnancy. They are additionally referred to maternal fetal medicine for further counseling on the effect of various treatments on the fetus and neonate, and for a discussion on neonatal outcomes in women with migraine.”

OnabotulinumtoxinA has been at the center of migraine discussion over the past few months. Allergan published additional results at AHS 2020 that evaluated pregnancy outcomes in onabotulinumtoxinA-exposed mothers in a cumulative 29-year safety update. They found that among the prospective cases in 152 live births, 148 (97.4%) of them had a normal outcome and only 4 (2.6%) had an abnormal outcome. These results were consistent with FDA guidance and other case studies, with major fetal birth defects occurring in 3% to 6% of the general population.²

Among the 4 patients who had abnormal outcomes, 1 was due to ventricular septal defect, otherwise considered a major fetal defect, 2 were minor fetal defects such as metalarsus and innocent asymptomatic cardiac murmur, and 1 was a birth complication stemming from Horner syndrome.²

Another study presented at AHS 2020 of patients with chronic migraine who had received the treatment while also been prescribed a calcitonin gene-related peptide (CGRP) monoclonal antibody medication demonstrated that the new class of medicines are safe and effective for those who need an additional preventive treatment.³

In early May, a study revealed that clinicians who had been treating patients with the therapy were using inter- and intrapersonal variations of the FDA-approved PREEMPT protocol. In total 141 of the 182 clinicians who responded to the survey reported that they did not always follow the protocol, ultimately raising concerns about the standardization of the procedure while also noting that more evidence and discussion behind the recommendations may help improve it going forward.⁴

For more AHS 2020 coverage, click here.

REFERENCES

1. Summers JE, Bedrin KO, Ailani J, Dougherty CO. Safety of using onabotulinumtoxinA for the treatment of chronic migraine in pregnancy. Headache. 2020;60(S1 Suppl). 1—156. doi: 10.1111/head.13854.

2. Brin MF, Kirby RS, Slavotinek A, et al. Pregnancy outcomes following exposure to onabotulinumtoxinA update: 29 years of safety observation. Headache. 2020;60 (S1 Suppl). 1­­—156. doi: 10.1111/head.13854.

3. Cohen F, Armand C, Vollbracht S. Efficacy and Tolerability of CGRP Monoclonal Antibody Medications in Patients with Chronic Migraine Undergoing Treatment with OnabotulinumtoxinA. Headache. 2020;60(S1 suppl). 1-156. doi: 10.1111/head.13854

4. Begasse de haem O, Gharedaghi MH, Rizzoli P. Modifications to the PREEMPT protocol for onabotulinumtoxinA injections for chronic migraine in clinical practice. Headache. Published online April 25, 2020. doi: 10.1111/head.13823.