A new and very promising preventive treatment for cluster headaches being developed by Eli Lilly may become available in the near future. We hope that the FDA recognizes that this is a relatively rare condition with few available treatments and will not require extensive clinical trials, especially because the safety of this drug has been demonstrated in a large number of migraine patients.
CGRP monoclonal antibodies are very effective for the prevention of migraines and four companies are developing such drug. Thankfully, one of these companies, Eli Lilly decided to study this type of treatment for cluster headaches. The company just announced the results of a phase 3 trial in 106 patients that showed their product, galcanezumab to be effective in preventing episodic cluster headaches. The drug did not help prevent attacks in patients with chronic cluster headaches, which constitute 10-15% of cluster patients.
Last week, the first CGRP monoclonal antibody, erenumab (Aimovig) was approved for the preventive treatment of migraine headaches. Considering that all four CGRP drugs are similar, it is possible that erenumab is also effective for cluster headaches. However, because it was not studied for this indication and has no FDA-approval, insurance companies are not likely to pay for it. On the other hand, cluster attacks last one to three months, so the cost is less prohibitive than it is for the long-term treatment of migraines and patients are more desperate to find relief at any cost.
Cluster headaches affect less than 0.5% of the population (mostly men), but they are often excruciating and sometimes described as suicidal. The name cluster comes from the fact that these headaches occur daily for a month or two and then go away for a year. Chronic cluster headaches continue to occur for more than a year without a break. Each attack lasts anywhere from 15 minutes to a couple of hours, often waking the patient from sleep, usually at the same time of night. The pain is always on one side, around the eye and sometimes at the back of the head. Besides pain, patients experience tearing and nasal congestion on the side of the headache. Unlike with migraine, where patients try to lie quietly and not move, cluster attacks lead to agitation, restlessness, pacing and even hitting the head with a fist or against a hard object.
The only FDA-approved treatment for cluster headaches is injection of sumatriptan (Imitrex, Imigran) to abort each individual attack. This drug is also approved for migraines, indicating that there are similarities between these conditions. Other abortive treatments included inhalation of oxygen and intranasal zolmitriptan (Zomig NS), while tablets tend to be too slow to work. For prevention, we use occipital nerve blocks, a course of steroids or daily drugs, such as verapamil (Calan).
Most of these older treatments work for about 50% of patients, so it is very exciting to have a highly effective treatment that was specifically developed for cluster headaches.
