A multi-center double-blind pilot comparison of onabotulinumtoxinA and topiramate for the prophylactic treatment of chronic migraine

(Headache 2011;51:21‐32) Objective.— This multi‐center pilot study compared the efficacy of onabotulinumtoxinA with topiramate (a Food and Drug Administration approved and widely accepted treatment for prevention of migraine) in individuals with chronic migraine (CM). Methods.— A total of 59 subjects with CM were randomly assigned to one of 2 groups: Group 1 (n = 30) received topiramate plus placebo injections, Group 2 (n = 29) received onabotulinumtoxinA injections plus placebo tablets. Subjects maintained daily headache diaries over a 4‐week baseline period and a 12‐week active study period. The primary endpoint was the Physician Global Assessment, which measured the treatment responder rate and indicated improvement in both groups over 12 weeks. Secondary endpoints, measured at weeks 4 and 12, included headache days per month, migraine days, headache‐free days, days on acute medication, severity of headache episodes, Migraine Impact & Disability Assessment, Headache Impact Test, effectiveness of and satisfaction with current treatment on the amount of medication needed, and the frequency and severity of migraine symptoms. At 12 weeks subjects were re‐evaluated and tapered off oral study medications over a 2‐week time period. Subjects not reporting a >50% reduction of headache frequency at 12 weeks were invited to participate in a 12‐week open label extension study with onabotulinumtoxinA. Of these, 20 subjects, 9 from the Topiramate Group and 11 from the OnabotulinumtoxinA Group, volunteered for this extension from weeks 14 to 26. Results.— This study demonstrated positive benefit for both onabotulinumtoxinA and topiramate in subjects with CM. Overall, the results were statistically significant within groups but not between groups. By week 26, subjects had a reduction of headache days per month compared with baseline. This was a significant within‐group finding. Conclusion.— OnabotulinumtoxinA and topiramate demonstrated similar efficacy for subjects with CM as determined by Global Physician Assessment and supported by multiple secondary endpoint measures.     

Botulinum Toxin Type A for Glabellar Frown Lines: What Impact of Higher Doses on Outcomes?

Botulinum toxin serotype-A (BoNT-A) preparations are widely used to improve the appearance of wrinkles. While effective and well tolerated, patients require retreatment over time to re-establish the effects. There is growing interest from patients as to whether higher doses can prolong response without significantly increasing side effects. We reviewed the efficacy and safety evidence for high-dose BoNT-A treatment of glabellar lines, by evaluating high-dose studies published since 2015. Toxins approved for glabellar line treatment in the US or Europe were considered. “High-dose” indicated doses above the licensed dose for each BoNT-A preparation. Five studies met the inclusion criteria and most were randomized, double-blind trials; designs and population sizes varied. Findings suggested that higher-dose BoNT-A treatment is feasible and may improve response duration without increased safety issues. Around 9 months’ median duration was achieved with a 2–2.5-fold increase of the abobotulinumtoxinA on-label dose, or with a 5-fold increase in incobotulinumtoxinA dose. A 2–4-fold increase of the onabotulinumtoxinA on-label dose yielded a median duration of around 6 months. Importantly, patient satisfaction and natural look remained with increasing abobotulinumtoxinA doses. While more data are needed, these findings may lead to more effective, individually tailored treatment plans to meet patient expectations.     

Two Mechanisms Involved in Trigeminal CGRP Release: Implications for Migraine Treatment

Objective/Background.— The goal of this study was to better understand the cellular mechanisms involved in proton stimulation of calcitonin gene‐related peptide (CGRP) secretion from cultured trigeminal neurons by investigating the effects of 2 antimigraine therapies, onabotulinumtoxinA and rizatriptan. Stimulated CGRP release from peripheral and central terminating processes of trigeminal ganglia neurons is implicated in migraine pathology by promoting inflammation and nociception. Based on models of migraine pathology, several inflammatory molecules including protons are thought to facilitate sensitization and activation of trigeminal nociceptive neurons and stimulate CGRP secretion. Despite the reported efficacy of triptans and onabotulinumtoxinA to treat acute and chronic migraine, respectively, a substantial number of migraineurs do not get adequate relief with these therapies. A possible explanation is that triptans and onabotulinumtoxinA are not able to block proton‐mediated CGRP secretion. Methods.— CGRP secretion from cultured primary trigeminal ganglia neurons was quantitated by radioimmunoassay while intracellular calcium and sodium levels were measured in neurons via live cell imaging using Fura‐2 AM and SBFI AM, respectively. The expression of acid‐sensing ion channel 3 (ASIC3) was determined by immunocytochemistry and Western blot analysis. In addition, the involvement of ASICs in mediating proton stimulation of CGRP was investigated using the potent and selective ASIC3 inhibitor APETx2. Results.— While KCl caused a significant increase in CGRP secretion that was significantly repressed by treatment with ethylene glycol tetraacetic acid (EGTA), onabotulinumtoxinA, and rizatriptan, the stimulatory effect of protons (pH 5.5) was not suppressed by EGTA, onabotulinumtoxinA, or rizatriptan. In addition, while KCl caused a transient increase in intracellular calcium levels that was blocked by EGTA, no appreciable change in calcium levels was observed with proton treatment. However, protons did significantly increase the intracellular level of sodium ions. Under our culture conditions, ASIC3 was shown to be expressed in most trigeminal ganglion neurons. Importantly, proton stimulation of CGRP secretion was repressed by pretreatment with the ASIC3 inhibitor APETx2, but not the transient receptor potential vanilloid‐1 antagonist capsazepine. Conclusions.— Our findings provide evidence that proton regulated release of CGRP from trigeminal neurons utilizes a different mechanism than the calcium and synaptosomal‐associated protein 25‐dependent pathways that are inhibited by the antimigraine therapies, rizatriptan and onabotulinumtoxinA.     

Adverse Events of Intravesical OnabotulinumtoxinA Injection between Patients with Overactive Bladder and Interstitial Cystitis—Different Mechanisms of Action of Botox on Bladder Dysfunction?

Intravesical onabotulinumtoxinA (BoNT-A) injections have been proposed to treat both overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS) in patients with refractory conditions. We compared adverse events (AEs) after BoNT-A treatment between IC/BPS and OAB in women. IC/BPS patients who failed conventional treatments were enrolled to receive suburothelial injections of BoNT-A (100 U) followed by hydrodistention. Age matched OAB female patients refractory to antimuscarinic agents underwent BoNT-A (100 U) injections. The bladder capacity, maximum flow rate (Qmax), post-void residual (PVR), and voiding efficiency (VE) at baseline, 3 and 6 months, and the post-treatment AEs were analyzed between groups. Finally, 89 IC/BPS and 72 OAB women were included. In the OAB group, the bladder capacity and PVR increased, and VE decreased significantly at three and six months after BoNT-A treatment. In the IC/BPS group, the Qmax increased significantly at six months. There were significant differences in changes of capacity, Qmax, PVR and VE between the two groups. Moreover, OAB patients suffered more frequently from events of hematuria, UTI, and large PVR (>200 mL), but less frequently from events of straining to void. In conclusion, OAB women had higher PVR volume and lower VE than those in IC/BPS after BoNT-A injections. These results imply that the bladder contractility of OAB patients are more susceptible to BoNT-A, which might reflect the different mechanisms of action of Botox on bladder dysfunction. Further investigations to confirm this hypothesis are warranted.