The triptan era
Sumatriptan was developed by Glaxo for the acute treatment of migraine. The medication, first available only as self-administered subcutaneous injections, was originally designed to bind to vascular serotonin receptors to allow selective constriction of cranial vessels that dilate, causing pain, during a migraine attack. (Years later it was discovered that triptans also worked as anti-inflammatory agents that decreased the release of the neurotransmitter calcitonin gene-related peptide, or CGRP.)
Triptans “changed the world for migraine patients and for me,” Dr. Rapoport said. “I could now prescribe a medication that people could take at home to decrease or stop the migraine process in an hour or two.” The success of the triptans prompted pharmaceutical companies to search for new, more effective ways to treat migraine attacks, with better tolerability.
Seven different triptans were developed, some as injections or tablets and others as nasal sprays. “If one triptan didn’t work, we’d give a second and rarely a third,” Dr. Rapoport said. “We learned that if oral triptans did not work, the most likely issue was that it was not rapidly absorbed from the small intestine, as migraine patients have nausea, poor GI absorption, and slow transit times. This prompted the greater use of injections and nasal sprays.” Headache specialists began combining triptan treatment with nonsteroidal anti-inflammatory drugs, offering further relief for the acute care of migraine.
Medication overuse headache
The years between 1993 and 2000, which saw all the current triptan drugs come onto the market, was an exhilarating one for headache specialists. But even those who were thrilled by the possibilities of the triptans, like Dr. Rapoport, soon came to recognize their limitations, in terms of side effects and poor tolerability for some patients.
Specialists also noticed something unsettling about the triptans: that patients’ headaches seemed to recur within a day, or occur more frequently over time, with higher medication use.
Medication overuse headache (MOH) was known to occur when patients treated migraine too often with acute care medications, especially over-the-counter analgesics and prescription opioids and barbiturates. Dr. Rapoport began warning at conferences and in seminars that MOH seemed to occur with the triptans as well. “In the beginning other doctors didn’t think the triptans could cause MOH, but I observed that patients who were taking triptans daily or almost daily were having increased headache frequency and the triptans stopped being effective. If they didn’t take the drug they were overusing, they were going to get much worse, almost like a withdrawal.”
Today, all seven triptans are now generic, and they remain a mainstay of migraine treatment: “Almost all of my patients are using, or have used a triptan,” Dr. Rapoport said. Yet researchers came to recognize the need for treatments targeting different pathways, both for prevention and acute care.
The next revolution: CGRP and gepants
Studies in the early 2000s began to show a link between the release of one ubiquitous nervous system neurotransmitter, calcitonin gene-related peptide, or CGRP, and migraine. They also noticed that blocking meningeal inflammation could lead to improvement in headache. Two new drug classes emerged from this science: monoclonal antibodies against CGRP or its receptor that had to be given by injection, and oral CGRP receptor blockers that could be used both as a preventive or as an acute care medication.
In 2018 the first monoclonal antibody against the CGRP receptor, erenumab (Aimovig, marketed by Amgen), delivered by injection, was approved for migraine prevention. Three others followed, most given by autoinjector, and one by IV infusion in office or hospital settings. “Those drugs are great,” Dr. Rapoport said. “You take one shot a month or every 3 months, and your headaches drop by 50% or more with very few side effects. Some patients actually see their migraines disappear.”
The following year ubrogepant (Ubrelvy, marketed by AbbVie), the first of a novel class of oral CGRP receptor blockers known as “gepants,” was approved to treat acute migraine. The FDA soon approved another gepant, rimegepant (Nurtec, marketed by Pfizer), which received indications both for prevention and for stopping a migraine attack acutely.
Both classes of therapies – the antibodies and the gepants – are far costlier than the triptans, which are all generic, and may not be needed for every migraine patient. With the gepants, for example, insurers may restrict use to people who have not responded to triptans or for whom triptans are contraindicated or cause too many adverse events. But the CGRP-targeted therapies as a whole “have been every bit as revolutionary” as the triptans, Dr. Rapoport said. The treatments work quickly to resolve headache and disability and get the patient functioning within an hour or two, and there are fewer side effects.
In a review article published in CNS Drugs in 2021, Dr. Rapoport and his colleagues reported that the anti-CGRP treatment with gepants did not appear linked to medication overuse headache, as virtually all previous acute care medication classes did, and could be used in patients who had previously reported MOH. “I am confident that over the next few years, more people will be using them as insurance coverage will improve for patients living with migraine,” he said.
Headache treatment today
Migraine specialists and patients now have a staggering range of therapeutic options. Approved treatments now include prevention of migraine with onabotulinumtoxinA (Botox, marketed by the Allergan division of AbbVie) injections, which work alone and with other medicines; acute care treatment with ditans like lasmiditan (Reyvow, marketed by Lilly*), a category of acute care medicines that work like triptans but target different serotonin receptors. Five devices have been cleared for migraine and other types of headache by the FDA. These work alone or along with medication and can be used acutely or preventively. The devices “should be used more,” Dr. Rapoport said, but are not yet well covered by insurance.
Thirty years after the triptans, scientists and researchers continue to explore the pathophysiology of headache disorders, finding new pathways and identifying new potential targets.
“There are many parts of the brain and brain stem that are involved, as well as the thalamus and hypothalamus,” Dr. Rapoport said. “It’s interesting that the newer medications, and some of the older ones, work in the peripheral nervous system, outside the brain stem in the trigeminovascular system, to modulate the central nervous system. We also know that the CGRP system is involved with cellular second-order messengers. Stimulating and blocking this chain of reactions with newer drugs may become treatments in the future.”
Recent research has focused on a blood vessel dilating neurotransmitter, pituitary adenylate-cyclase-activating polypeptide, or PACAP-38, as a potential therapeutic target. Psychedelic medications such as psilocybin, strong pain medications such as ketamine, and even cannabinoids such as marijuana have all been investigated in migraine. Biofeedback therapies, mindfulness, and other behavioral interventions also have proved effective.
“I expect the next 2-5 years to bring us many important clinical trials on new types of pharmacological treatments,” Dr. Rapoport said. “This is a wonderful time to be a doctor or nurse treating patients living with migraine. When I started out treating headache, 51 years ago, we had only ergotamine tartrate. Today we have so many therapies and combinations of therapies that I hardly know where to start.”
Dr. Rapoport has served as a consultant to or speaker for AbbVie, Amgen, Biohaven, Cala Health, Lundbeck, Satsuma, and Teva, among others.
*Correction, 3/30/23: An earlier version of this article misstated the name of the company that markets Reyvow.