Name: Azetukalner (XEN1101) in Focal onset seizures: Mechanism of action
Published: 2026-09-21T21:41:53-04:00

Potassium channel opening and neuronal hyperpolarization

“Azetukalner is designed to open potassium channels in the central nervous system, allowing potassium ions to flow and hyperpolarizing neurons. This process helps reduce excessive neuronal firing, which is a key contributor to several neurologic and psychiatric disorders.” (opens the source at this quote in a new tab)

Stabilization of the open channel state

“By stabilizing the open state of these channels, it promotes a hyperpolarized resting membrane potential, thereby reducing rapid action potential spiking.” (opens the source at this quote in a new tab)

In vitro potency at KV7.2 and KV7.2/7.3 channels

“In these systems, azetukalner was found to activate Kv7.2 channels with half-maximal effective concentrations (EC50) of 11 and 15 nM, respectively. In a Xenopus oocyte expression system, azetukalner activated channels Kv7.2, Kv7.5, Kv7.4, and Kv7.2/7.3 heteromer with EC50 values of 0.45, 0.35, 0.63, and 0.35 µM, respectively” (opens the source at this quote in a new tab)

Subtype selectivity within the KV7 family

“In in vitro studies in CHO cell lines expressing heteromeric Kv7.2/7.3 and Kv7.3/7.5 channels and homomeric Kv7.4 channels, azetukalner showed 3.4-fold greater selectivity for Kv7.2/7.3 over Kv7.3/7.5 and Kv7.4 channels, with EC50 values of 27 nM versus 94 nM and 113 nM, respectively” (opens the source at this quote in a new tab)

Selectivity over other ion channels and the GABA system

“Azetukalner reportedly exerts no activity on other ion channels or the GABA system at concentrations > 100-fold greater than those active on Kv7.2 channels” (opens the source at this quote in a new tab)

Relative rather than absolute selectivity

“Reported selectivity is subtype-relative rather than absolute: in heterologous expression assays azetukalner is approximately fourfold more potent at KV7.2/7.3 than at KV7.3/7.5 or KV7.4, with screening selectivity over unrelated channels and receptors reported as greater than 100-fold, including absence of the GABAA activity seen with retigabine.” (opens the source at this quote in a new tab)

Potency relative to ezogabine

“In studies with human embryonic kidney (HEK) cells expressing Kv7.2/7.3 channels, azetukalner (EC50, 42 nM) was 20 times more potent than ezogabine (EC50, 920 nM) in causing an approximate 40 mV leftward (negative) shift in the half-maximal voltage of channel activation, while causing a similar increase in maximal conductance” (opens the source at this quote in a new tab)

Structural difference from ezogabine

“The novel structure differs from that of ezogabine.” (opens the source at this quote in a new tab)

Structural basis for bypassing the pigment-forming pathway

“It was designed to bypass the pigment-forming pathway associated with retigabine” (opens the source at this quote in a new tab)
“Unlike retigabine, which bears a secondary aromatic amino group, the amino functionality of azetukalner is incorporated within a tetrahydroisoquinoline ring system, which sterically and electronically constrains the nitrogen atom and prevents 1 from participating in oxidative dimerization.” (opens the source at this quote in a new tab)