Comparative Long-Term Effectiveness Of OnabotulinumtoxinA (Botox) And Anti CGRP In Migraine Prevention: A Systematic Review

Search methods

The databases and search engines utilized for this analysis included The Cochrane Library, Medline, and PubMed. Our search targeted studies published from 2015 to 2024, aiming to provide a comprehensive review of the literature. Despite the presence of numerous systematic studies in the field, our research brings updated insights into the effectiveness of anti-CGRP monoclonal antibodies (mAbs) and Botulinum toxin type A (BoNT-A) for migraine prevention. To integrate relevant concepts with specific keywords, we used Boolean operators “AND” and “OR,” as outlined in Table 2. In our meticulous selection process, we included publications in various languages, and abstract-only papers were also considered, adhering to the “Human studies only” screening criterion to ensure a broad and inclusive review of the available evidence. Ethics approval was not required for this systematic review.

Inclusion criteria

The criteria used to select the research studies included are as follows:

Exclusion criteria

Papers that did not discuss the BoNT-A and CGRP mAbs in CM were excluded. Articles published in languages other than English must be removed due to the difficulties in translating them. Publications that contained passages from the original papers but did not fully relate to the review's subject matter were also disregarded. Every article in the review discussed how CGRP mAbs and BoNT-A in CM affect a patient's risk assessment during physical therapy.

Evaluation of quality

The Critical Appraisal Skills Programme or CASP checklist,³⁸ was used to evaluate the dependability and competence of the selected research projects. CASP is one of the most useful evaluation methods since the reviewers have chosen the research papers for the systematic reviews. A high, low, or unknown category was assigned to each of the possible causes of bias: poor assessments, measurement mistakes, selective clinical effectiveness, and schedule setting. The primary objective of the quality evaluation process was to use evidence to support quality assessment. The systematic review was assessed using a 10-item checklist (see Table 1). Several considerations were made, including the method's validity, the findings' efficacy, and the dependability of the research designs. Several elements with low accuracy are eliminated in the assessment of external validity, which also considers the small sample size and precision of the results. The following is a list of the checklist's score criteria.

Data extraction

First, eligible publications were reviewed according to the Center for Reviews and Dissemination standards for title and abstract.³⁹ After being verified, duplicate articles were eliminated. The whole text of the qualifying records was obtained after duplicates were eliminated, and two experienced investigators assessed the articles' eligibility. Subsequently, one investigator extracted the necessary data, and two more verified it; disagreements or opinions were settled by discussion and agreement with the principal investigator. Evidence from each publication was obtained before the research projects were released as papers.

Data items

Information sources

Migraine pathophysiology

The premonitory phase, starting three days before the headache phase, is distinguished by an intricate interaction between many cortical and subcortical of the brain, such as the brainstem nuclei and hypothalamus, which regulate nociceptive transmission. The headache episode involves the trigeminovascular system being activated.⁵³ Chronic headache is defined as 15 or more days of cerebral discomfort per month for three months or more, with migraine spikes occurring at least eight days per month, according to the International Classification of Headache Disorders, third edition (ICHD-3).⁵⁴ Several brainstem levels, including the hypothalamus and basal ganglia nuclei, receive signals from the Trigeminocervical complex (TCC) via ascending pathways. Nuclei project to different cortical locations, processing nociceptive impulses and resulting in symptoms including light sensitivity, loud noises, smell, touch, and neurocognitive disorder.

Effectiveness of botox

They are a widely recognized example of neurotoxins with several FDA-approved therapeutic applications, such as managing spastic bladder, preventing cerebral discomfort, and effectively relaxing cervical dystonia.⁵⁵ Even though the effects are temporary, they may be altered by altering the organization's sum and recurrence. Botox, one of the worst naturally occurring risks, was just made available for medical use, but not before it caused many accidental deaths. It was initially used in medicine to treat strabismus in 1980. Strabismus is a condition when neither eye lines up in the same way. Although the cosmetic benefits of Botox for wrinkles were first identified in 1989, it wasn't until 2002 that the treatment gained widespread recognition as a viable therapeutic option following FDA approval.⁵⁶ In 2014, Ali et al. discovered that Botox suppresses mechanical pain in peripheral trigeminovascular neurons. It is believed that meningeal and trigeminal nociceptors have a significant role in the development of severe migraines. According to Ali et al., BoNT-A reduces the onset of headaches by inhibiting high-threshold, mechanosensitive particle pathways implicated in mechanical pain from joining into the terminals of the nerve layer.⁵⁵

There are several advantages of Botox over additional preventive drugs. In 2018, a cohort study was conducted on 245 individuals who had persistent headaches and had received BoNT-A injections at varying periods. Eighty patients made it through the exploration, and 82.8% declared that Botox had helped them feel more in control of their migraines.⁵⁷ A more extensive, double-blind, randomized study with 1,384 participants was conducted in 2010; 688 patients received Botox treatments, while 696 patients received placebos. The frequency of migraine recurrence was significantly reduced in patients who received Botox.³⁵ Furthermore, compliance was considered more accessible because this approach is repeated every 12 weeks. The efficacy, safety, and cost-benefit analyses of these medications may help clinicians make more informed treatment decisions based on the study's findings.⁴¹ There were no particularly notable long-term antagonistic effects except the standard Botox effects. In one research that included children, Botox was proven to be safe and effective in younger individuals. Because migraines can occur at any age, some people begin to experience headaches as early as childhood. According to the findings of a clinical experiment, a group of six individuals aged 14 to 18 who had not responded to prior migraine preventive treatments were given Botox during a clinical trial. Every sixth participant reported fewer headaches without significant side effects.⁴⁹

Anti-CGRP mechanism of action

One significant neurotransmitter connected to migraines is CGRP. Monoclonal antibodies and anti-CGRP agonists are effective migraine preventives. The nociceptive neuron cell terminals emit a vasoactive neuropeptide called CGRP—hereditary variations in locus heterogeneity result in various CGRP isoforms. According to a survey regarding the effectiveness of monoclonal antibodies against CGRP, the medications were successful and maintained for several trials. People found it more straightforward to have many prescription medicines since mAbs are not compatible with other medications because they are transformed into amino acids and peptides. These monoclonal antibodies that fight against CGRP must be taken monthly, in contrast to the daily usage of many of the earlier preventive drugs. As a result, patients can follow their treatment regimens.⁴⁹

Botox versus anti-CGRP

BoNT-A and CGRP monoclonal antibodies are used to treat CM. This section will examine the viability, side effects, cost-effectiveness, and other factors of CGRP mAbs and BoNT-A.⁴⁹ A total of 1,672 patients were randomly assigned to groups that received varying doses of galcanezumab and a placebo. A total of 1,672 individuals were randomized randomly to receive either galcanezumab at a dosage or a placebo. 60.9% of patients experienced a reduction of more than 50% in migraine occurrences when taking 240 mg. Without having any unfavorable side effects, it has been shown that CGRP mAb lessens migraines.⁴⁹ Table 4 summarizes the difference between the application of BoNT-A and anti-CGRP.

Additionally, they have no adverse hepatotoxic effects and are not associated with other medications. Compliance was advanced since it was handled once a month instead of regularly. In a retrospective analysis, all medical records from July 1, 1994, to December 1, 2017, were reviewed to see if patients had received migraines with aura at least a single session of Botox injections. They were following a review of the medical records of the remaining eleven patients (seven with a rare type of migraine, i.e., aura migraine, and four with an inherited subtype of migraine, the frequency and type of the patient's headaches before and following receiving Botox were documented. Nine of the eleven research participants reported decreased frequency, intensity, and duration of their auras following Botox administration.⁵⁸ About week nine or ten of the 12-week course, six out of the nine people with improved aura symptoms reported the effects of Botox and improvements occurring in the subsequent cycle.⁵⁸

In one study, researchers did a retrospective file evaluation of patients who had both Botox and a CGRP-mAb to ascertain whether additional treatment with CGRP-mAbs improves Botox treatment in CM sufferers. Patients who met the criteria for chronic headaches and were at least eighteen years old made their initial appointment at a single headache center. Individuals who had CGRP-mAb treatment for less than two months or who switched medications throughout the trial were not allowed to participate. The primary goal of the experiment was to determine whether the number of reported monthly headache days varied. The change in the severity of the pain was the secondary outcome. It is safe and beneficial to use CGRP-mAb medication as a supplemental preventive treatment in individuals with CM who have only partially responded to Botox. The researchers found that the CGRP-mAbs significantly reduced the number of days experiencing headaches and pain intensity and that the adverse event rates were similar to those observed in other trials with these medications.⁵⁹

It's noteworthy to note a lot of the triggers, such as hunger, lack of sleep, or bright light, that migraine patients point out could be premonitory indicators of a migraine attack that is actively in progress. This relationship explains why findings in clinical studies intended to identify and validate migraine trigger factors prospectively often diverge from findings in survey-based studies, where participants essentially describe their historical perspective of factors causing their migraine attacks.⁶⁰ Most medications on the market now that prevent migraines were developed to treat other conditions. This may help to explain some of the tolerability issues with some medications. First-line preventive drugs from the antidepressant medicine, anti-hypertensive, antiepileptic, and calcium channel blocker categories, among others, are still often used because clinical trials have shown them to be effective.⁵⁸

Even though these medicines assist up to 50% of migraineurs in reducing the total number of days they confront headache pain each month, none of the conventional oral preventive medications, which include beta-blockers, tricyclic antidepressants, serotonin antagonists, antidepressant medications, and anti-epileptic drugs were developed to treat headaches. Furthermore, there is often poor adherence to these drugs due to their poor tolerance.⁶¹ Although Botox has been linked to notable clinical relief for those with CM, it usually isn't able to lower the frequency of headaches; therefore, other drugs are needed.⁴² The guidelines' recommendations include a series of micro-injections between 31 and 39 used to administer Botox. These are injected into the muscular tissues of the neck, forehead, and region above the ears, either directly or beneath the skin. The physician is qualified to give Botox for the treatment of severe migraines. Injections are given every 12 weeks. Botox is usually used until three consecutive months of episodic migraine attacks or until quality-of-life surveys demonstrate a noticeable decrease in the level of impairment. The Botox treatment may be discontinued if it doesn't significantly lessen your migraines.^42,43 Migraine sufferers are treated with the same injections used by cosmetic surgeons and dermatologists to minimize wrinkles on the face. Qualified medical professionals treat migraines by injecting botulinum toxin into different parts of the head and neck; prophylactic medications are intended to reduce the incidence of migraine attacks.⁴²

A review of the most recent research on the function of CGRP in the digestive system suggests that the protein may reduce food intake, inhibit colon contractions in rats, and minimize stomach emptying. Some of these effects were local, while others were indirect, using neuronal CGRP receptors. The purpose of this study was to advance the understanding of a crucial gastrointestinal target for CGRP, which could be helpful in the understanding of constipation caused by anti-CGRP therapy and perhaps provide a medication choice for those experiencing constipation.⁶² As a result, the majority of migraine specialists consider these drugs to impact CGRP outside of the CNS, maybe in the meninges, which are the membranes covering the brain and skull, which is where migraine pain may initially arise.⁶³

Botox and CGRP monoclonal antibodies have advantages over one another when managing migraines but also disadvantages. CGRP mAbs need monthly self-injections from patients, and adverse symptoms, such as redness and itching at the site of injection, have been documented. Additionally, some patients may find it less accessible because it is an expensive medication that may run up to $600 dollars a month without insurance.⁶⁰ Even though CGRP mAb and Botox infusions have different mechanisms of action, they appear t to work similarly in blocking the sensations of pain channels that cause headaches. Reduced acetylcholine release at neuromuscular connections is how Botox functions; meanwhile, it is believed that CGRP mAbs suppress pain perception by irritating an obvious burning marker like CGRP.

Subsequent searches that examined the effectiveness of anti-CGRP and included significant test measures showed that such drugs were effective headache preventives. Various studies have demonstrated the benefits of Botox throughout the last ten years. Regarding adverse effects, BoNT-A and anti-CGRP have direct, temporary antagonistic effects; overall, an adverse long-standing impact unique to CGRP mAb users was at a standstill.⁶¹

The CGRP mAb infusions are also significantly more painful than Botox injections. When analyzing BoNT-A and anti-CGRP, cost-effectiveness should be taken into account. Even while some insurance plans cover both medications entirely or partly, those without assurance may not be able to purchase any of these prescriptions. BoNT-A is typically the less expensive medication over the long term, so that it might be a sensible option for people on a tight budget. According to the reviewed papers, Botox may be a better option for treating migraines than CGRP mAbs because it is easier, less expensive, and more effective.⁴⁹

Limitations

Even though the researcher used the available platform to conduct an extensive evaluation, the researcher must consider the possibility that the researcher overlooked significant research. Because the researcher only included papers from a limited number of databases and did not have full access to publications. All the research examined for this study was selected only written in English. A limited number of study publications compared anti-CGRP with Botox. However, this assumption is unsubstantiated because most of the included studies did not include any information on ethnicity. Secondly, not enough trials were included, affecting the accuracy of the effect estimations. The researcher needs to make an effort to conduct a more thorough investigation to compare these two appropriately.