SK Biopharmaceuticals, a South Korea-based drugmaker that already sells an FDA-approved epilepsy medicine, is expanding its U.S. strategy with a deal for a late-stage molecule from Biohaven that brings a different mechanism of action to the seizure disorder.
SK will pay $400 million up front for global rights to the Biohaven drug, opakalim, according to deal terms announced Aug. 26. This Biohaven drug is on track to yield preliminary Phase 2/3 data by the end of this year. A second data readout is expected in 2028. If the drug passes FDA muster, Seoul-based SK said it plans to launch opakalim in the U.S. in 2029.
In epilepsy, the abnormal flow of charged ions across cell membranes leads to bursts of electricity in the brain. Opakalim is an activator of Kv7, a protein that forms channels that act like brakes to suppress this abnormal signaling. Biohaven added opakalim to its pipeline via the $100 million purchase of Channel Bio. When that deal was struck in 2022, the molecule, then known as BH7-7000, was approaching Phase 1 testing. The acquisition included the platform technology that produced this epilepsy drug.
Biohaven has since advanced opakalim to Phase 3 testing in focal onset epilepsy. The drug faces potential competition in this space. Xenon Pharmaceuticals is in late-stage clinical development with a Kv7-targeting drug, azetukalner. Last year, Jazz Pharmaceuticals licensed rights to Saniona’s SAN2355, a preclinical small molecule designed to selectively activate Kv7.2 and Kv7.3, two subtypes of Kv7.
SK’s upfront payment to Biohaven breaks down to $350 million upon deal closing and $50 million one year after. SK could pay Biohaven up to $395 million more tied to the achievement of milestones, plus royalties from sales of an approved product. A portion of those payments will go to Knopp Biosciences, the company that originally developed opakalim and formed Channel Bio.
As of June 30, Biohaven reported its cash position was about $270.5 million. Leerink Partners analyst Marc Goodman said in a research note that outlicensing opakalim makes sense for Biohaven, as this late-stage drug is the company’s most valuable asset and the deal with SK brings non-dilutive capital. He added that Biohaven doesn’t view itself as a epilepsy company, and it has previously struck business deals involving its neuro assets to raise money for other programs. In 2022, Pfizer acquired Biohaven Pharmaceuticals to get the oral migraine drug Nurtec. The remaining assets were spun out into the current iteration of Biohaven, capitalized by cash from that deal.
Goodman said opakalim has a cleaner safer profile versus Xenon’s drug, but that raises debate among investors. While some believe cleaner safety indicates the drug is more selective to its target, others say it may be a sign of weaker target engagement.
William Blair analysts said the deal enables Biohaven to focus on key upcoming developments from the rest of its pipeline, including taldefgrobep alfa, a potential new obesity drug. This fusion protein, licensed from Bristol Myers Squibb, is designed to block myostatin and activin signaling to prevent muscle wasting and fat accumulation. Preliminary data from a Phase 2 study are expected by the end of the year. The Biohaven pipeline also includes two late-stage programs: BHV-1300 for Graves’ disease BHV-1400 for immunoglobulin A nephropathy.
As for SK, the William Blair analysts said licensing deal for opakalim is relatively inexpensive considering that peak sales of novel drugs for the focal segmental epilepsy indication alone are projected to reach $2 billion to $4 billion. But achieving those sales will depend on generating competitive Phase 3 data. The 42.7% placebo-normalized improvement on median monthly seizure frequency shown by Xenon’s azetukalner is “a truly remarkable result in a highly refractory population, along with an exceptional ease of use profile,” the analysts said. They added that the most likely opportunity for opakalim is to show differentiation on safety, not efficacy.
If approved, opakalim will slot into SK Life Science, the South Korean company’s New Jersey-based subsidiary that currently markets the anti-seizure medicine cenobamate, brand name Xcopri. Approved by the FDA in 2019, this small molecule drug inhibits sodium currents and modulates GABAA ion channels. In the announcement of the transaction with Biohaven, SK CEO Donghoon Lee said the deal will enable his company to commercialize multiple therapies in the U.S.
“This clearly signals that our company has stepped into the major leagues across all dimensions,” Lee said.
Photo: John Lund, Getty Images
