The release of CGRP inhibitors in the early 2020s was hailed as the "penicillin moment" for migraine. Drugs like Aimovig and Nurtec brought relief to millions. But reliable data from 2026 shows a hard truth: they don't work for everyone. Approximately 40% of patients are "CGRP non-responders."
For these patients, hope has arrived in the form of a different acronym: PACAP.
What is PACAP?
PACAP stands for Pituitary Adenylate Cyclase-Activating Polypeptide. Like CGRP, it is a neuropeptide, a signaling molecule used by nerve cells to communicate.
Research has discovered that PACAP, much like CGRP, is released in high quantities during a migraine attack and causes significant dilation of blood vessels. However, it operates on a completely different pathway.
- Distinct Pathways: Many patients who have normal CGRP levels during an attack have skyrocketing PACAP levels. This explains why CGRP blockers failed them, they were blocking the wrong door.
- The "Lu AG09222" Breakthrough: Early trials of the new antibody targeting PACAP (Lu AG09222) have shown dramatic efficacy in patients who had previously failed 2-4 other preventative treatments.
A New Hope for the Resistant
This is not just "another drug." It represents a shift towards multi-target therapy, blurring the lines between acute and preventive treatment.
Neurologists are beginning to categorize migraines not just by frequency (episodic vs. chronic), but by "Neuropeptide Dominance." In the near future, a simple test might tell you if you are a "CGRP Migraineur" or a "PACAP Migraineur," allowing for immediate targeted treatment.
For the millions who felt left behind by the CGRP revolution, PACAP research is the signal that science hasn't stopped looking for your cure.
Whether you respond to CGRP treatments or not, tracking your symptoms and treatment outcomes is essential. The Migraine Trail is a free migraine tracker app that helps you track migraine triggers, log medication responses, and build the data your doctor needs to find the right treatment for you.