Efficacy and safety of galcanezumab as a treatment of refractory episodic and chronic cluster headache: Case series and narrative review

Cluster headache: understandings of current knowledge and directions for whole process management

Cluster headache (CH) is a common primary headache that severely impacts patients' quality of life, characterized by recurrent, severe, unilateral headaches often centered around the eyes, temples, or forehead. Distinguishing CH from other headache disorders is challenging, and its pathogenesis remains unclear. Notably, patients with CH often experience high levels of depression and suicidal tendencies, necessitating increased clinical attention. This comprehensive assessment combines various reports and the latest scientific literature to evaluate the current state of CH research. It covers epidemiology, population characteristics, predisposing factors, and treatment strategies. Additionally, we provide strategic insights into the holistic management of CH, which involves continuous, individualized care throughout the prevention, treatment, and rehabilitation stages. Recent advances in the field have revealed new insights into the pathophysiology of CH. While these findings are still evolving, they offer a more detailed understanding of the neurobiological mechanisms underlying this disorder. This growing body of knowledge, alongside ongoing research efforts, promises to lead to the development of more targeted and effective treatments in the future.

Psilocybin pulse regimen reduces cluster headache attack frequency in the blinded extension phase of a randomized controlled trial

BACKGROUND

In a recent randomized, double-blind, placebo-controlled study, we observed a nonsignificant reduction of attack frequency in cluster headache after pulse administration of psilocybin (10 mg/70 kg, 3 doses, 5 days apart each). We carried out a blinded extension phase to consider the safety and efficacy of repeating the pulse regimen.

METHODS

Eligible participants returned to receive a psilocybin pulse at least 6 months after their first round of study participation. Participants kept headache diaries starting two weeks before and continuing through eight weeks after the first drug session. Ten participants completed the extension phase and all ten were included in the final analysis.

RESULTS

In the three weeks after the start of the pulse, cluster attack frequency was significantly reduced from baseline (18.4 [95% confidence interval 8.4 to 28.4] to 9.8 [4.3 to 15.2] attacks/week; p = 0.013, d' = 0.97). A reduction of approximately 50% was seen regardless of individual response to psilocybin in the first round. Psilocybin was well-tolerated without any unexpected or serious adverse events.

DISCUSSION

This study shows a significant reduction in cluster attack frequency in a repeat round of pulse psilocybin administration and suggests that prior response may not predict the effect of repeated treatment. To gauge the full potential of psilocybin as a viable medicine in cluster headache, future work should investigate the safety and therapeutic efficacy in larger, more representative samples over a longer time period, including repeating the treatment.

CLINICAL TRIALS REGISTRATION

NCT02981173.

Clinical predictors of therapeutic failure of occipital nerve stimulation in refractory chronic cluster headache

BACKGROUND

Occipital nerve stimulation (ONS) is a treatment with evidence in refractory chronic cluster headache (CCH). However, the variable response rate and cost make it necessary to investigate predictors of response.

METHODS

This is a cross-sectional study conducted through the review of medical records of CCH patients from six hospitals in Madrid. Epidemiological and clinical variables were compared between patients with ONS failure and the rest. ONS failure was defined as the need for device withdrawal or switch off because of lack of response or adverse events.

RESULTS

From a series of 88 CCH, 26 (29.6%) underwent ONS surgery, of whom 13/26 (50.0%) failed because lack of response. ONS failure group had an earlier headache onset (mean ± SD) of 27.7 ± 6.9 vs. 36.7 ± 11.8 years, p = 0.026) and a higher smoking rate (100% vs. 42.9%, p = 0.006). Stational fluctuations (58.3% vs. 7.7%, p = 0.007) and nocturnal exacerbations (91.7% vs. 53.9%, p = 0.035) were more frequent in the ONS failure group as well. There was no difference between groups in diagnostic delay, years of evolution prior to surgery, mental illness, comorbidity with other headache disorders or chronic pain conditions or prior response to occipital nerves anesthetic blocks.

CONCLUSIONS

Some clinical features such as an early debut, smoking and seasonal or circadian fluctuations could be related to failure of ONS in refractory CCH.

Efficacy and safety of galcanezumab as chronic cluster headache preventive treatment under real world conditions: Observational prospective study

BACKGROUND

Calcitonin gene-related peptide has shown to play a central role in cluster headache (CH) pathophysiology. A clinical trial with galcanezumab was carried out in chronic cluster headache (CCH) but did not meet its primay endpoint. However, its off-label use in patients with CCH refractory to other therapies could be considered. We aimed to asses the efficacy and safety of galcanezumab as CCH preventive treatment in a real-life setting.

METHODS

An observational study was conducted. Patients with CCH who received at least one dose of 240 mg of galcanezumab.

RESULTS

Twenty-one patients who tried a mean of 6.3 ± 1.9 preventive therapies, including onabotulinumtoxinA in 90.5%. At baseline, the median of frequency was 60 (37.5-105) monthly attacks with 10 (8.3-10) points in pain intensity (Numerical Rating Scale). After one month, the frequency decreased to 31 (10.5-45) (p = 0.003) with 8.5 (8-9.5) intensity (p = 0.007); 10 (47.6%) patients were 50% responders of whom four (19%) were 75% responders. Of the 15 patients with 3 months of follow-up, seven (46.6%) reduced their frequency by 50% and four (26.6%) by 75%, with 40 (10-60) monthly attacks (p = 0.07) and pain intensity of 8 (5-10) (p = 0.026). Some 52% patients experienced adverse events, mostly mild.

CONCLUSIONS

In our cohort of refractory CCH, galcanezumab was effective in almost 50% of patients. This finding supports individual off-label treatment attempts.

Health equity, care access and quality in headache - part 2

BACKGROUND

Headache disorders are a global public health concern affecting diverse populations. This review examines headache service organizations in low-, middle-, and high-income countries. It addresses global challenges in pharmacological headache treatment, with a focus on safety, tolerability, reproductive and child health, and outlines disparities in accessing innovative treatments worldwide.

MAIN BODY

Organized headache services are essential due to the wide prevalence and varying severity of headache disorders. The tiered headache service model is globally recognized, although its implementation varies based on financial and workforce considerations. Headache burden affects well-being, causing disability, economic challenges, and work limitations, irrespective of location or income. All nations still require improved diagnosis and treatment, and the majority of countries face obstacles including limited access, awareness, economic barriers, and inadequate health policies. Provided adequate internet availability, telemedicine could help improve health equity by expanding access to headache care, since it can offer patients access to services without lengthy waiting times or extensive travel and can provide healthcare unavailable in underserved areas due to staff shortages. Numerous health disparities restrict global access to many headache medications, especially impacting individuals historically excluded from randomized controlled trials, such as those with cardiovascular and cerebrovascular conditions, as well as pregnant women. Furthermore, despite advancements in researching migraine treatments for young patients, the options for treatment remain limited. Access to headache treatment relies on factors like medication availability, approval, financial coverage, and healthcare provider expertise. Inadequate public awareness leads to neglect by policymakers and undertreatment by patients and healthcare providers. Global access discrepancies are exacerbated by the introduction of novel disease-specific medications, particularly impacting Asian, African, and Latin American nations excluded from clinical trials. While North America and Europe experience broad availability of migraine treatments, the majority of countries worldwide lack access to these therapies.

CONCLUSIONS

Healthcare disparities, treatment access, and medication availability are concerning issues in headache medicine. Variations in national healthcare systems impact headache management, and costly innovative drugs are widening these gaps. Healthcare practitioners and experts should acknowledge these challenges and work towards minimizing access barriers for equitable global headache care in the future.

Preventive therapy with galcanezumab for two consecutive cluster bouts in patients with episodic cluster headache: an observational multicenter study

BACKGROUND

Cluster headache is a severe and disabling primary headache disorder. Galcanezumab is a monoclonal antibody against calcitonin gene-related peptide and a preventive therapy for episodic cluster headache. However, the approval and insurance coverage for episodic cluster headache differ in each country. Additionally, the consistency of efficacy of galcanezumab therapy has not yet been evaluated. This study aimed to assess the efficacy and safety of 240 mg of galcanezumab therapy for consecutive cluster bouts in patients with episodic cluster headache.

METHODS

The study enrolled patients with episodic cluster headache who received two courses of galcanezumab therapy at three university hospitals in Republic of Korea between February 2020 and April 2022. The efficacy and safety of galcanezumab were analyzed by comparing daily headache frequency, the number of headache days, and headache intensity and adverse effects during the one-week period before and the third week after galcanezumab injection for each episode of cluster bouts. Paired t-test was used for comparing repeated data from different episodes of cluster bout.

RESULTS

Sixteen patients were enrolled in this study. Fourteen patients received galcanezumab therapy for two consecutive cluster bouts. Galcanezumab was administered 24 days and 11 days after the first and second cluster bouts, respectively. The proportion of patients with 50% or more reduction in frequency of daily headache at week 3 from baseline was 86% and 64% during the first and second episodes, respectively. The proportion of patients who received transitional therapy before galcanezumab therapy was higher in the first episode of cluster bout than that in the second episode of cluster bout. No serious adverse reactions or significant differences in adverse effects between cluster bouts were noticed. Two patients received a second galcanezumab therapy during the pre-cluster period, and their cluster periods ended without typical cluster headache attacks 10-60 days after galcanezumab therapy.

CONCLUSIONS

This exploratory analysis suggests that galcanezumab may be effective as a preventive therapy in subsequent cluster bouts. Patients with episodic cluster headaches who underwent galcanezumab therapy tended to receive a second round of treatment in the early stages of their next cluster bout without transitional therapy.

Mode and site of action of therapies targeting CGRP signaling

Targeting CGRP has proved to be efficacious, tolerable, and safe to treat migraine; however, many patients with migraine do not benefit from drugs that antagonize the CGRPergic system. Therefore, this review focuses on summarizing the general pharmacology of the different types of treatments currently available, which target directly or indirectly the CGRP receptor or its ligand. Moreover, the latest evidence regarding the selectivity and site of action of CGRP small molecule antagonists (gepants) and monoclonal antibodies is critically discussed. Finally, the reasons behind non-responders to anti-CGRP drugs and rationale for combining and/or switching between these therapies are addressed.

Management of cluster headache: Treatments and their mechanisms

BACKGROUND

The management of cluster headache is similar to that of other primary headache disorders and can be broadly divided into acute and preventive treatments. Acute treatments for cluster headache are primarily delivered via rapid, non-oral routes (such as inhalation, nasal, or subcutaneous) while preventives include a variety of unrelated treatments such as corticosteroids, verapamil, and galcanezumab. Neuromodulation is becoming an increasingly popular option, both non-invasively such as vagus nerve stimulation when medical treatment is contraindicated or side effects are intolerable, and invasively such as occipital nerve stimulation when medical treatment is ineffective. Clinically, this collection of treatment types provides a range of options for the informed clinician. Scientifically, this collection provides important insights into disease mechanisms.

METHODS

Two authors performed independent narrative reviews of the literature on guideline recommendations, clinical trials, real-world data, and mechanistic studies.

RESULTS

Cluster headache is treated with acute treatments, bridge treatments, and preventive treatments. Common first-line treatments include subcutaneous sumatriptan and high-flow oxygen as acute treatments, corticosteroids (oral or suboccipital injections) as bridge treatments, and verapamil as a preventive treatment. Some newer acute (non-invasive vagus nerve stimulation) and preventive (galcanezumab) treatments have excellent clinical trial data for episodic cluster headache, while other newer treatments (occipital nerve stimulation) have been specifically tested in treatment-refractory chronic cluster headache. Most treatments are suspected to act on the trigeminovascular system, the autonomic system, or the hypothalamus.

CONCLUSIONS

The first-line treatments have not changed in recent years, but new treatments have provided additional options for patients.