When Slate Medicines launched early this year backed by a mega-round of financing, the company claimed best-in-class potential for its migraine drug candidate but offered few details. Now that Slate is joining the public markets in a merger deal, the company is revealing more about how it believes its drug can stand out in the $5 billion global market for migraine drugs.
The all-stock deal announced Monday has Slate set to merge with Nasdaq-listed Fulcrum Therapeutics. The combined company is keeping the Slate Medicines name and will be led by Gregory Oakes, the CEO of legacy Slate. The Slate pipeline will be supported by a $245 million infusion from investors betting on the Raleigh, North Carolina-based biotech’s prospects to top other migraine medicines from the same emerging drug class.
The antibody drugs now available for migraine are inhibitors of a protein called CGRP. Additional research has found that migraine pain is also associated with pituitary adenylate cyclase-activating polypeptide (PACAP), a different protein that, like CGRP, is found throughout the central nervous system. Slate’s SLTE-1009 was licensed from China-based DartsBio Pharmaceuticals. The drug is a monoclonal antibody designed to block two targets, PACAP and vasoactive intestinal peptide (VIP). This dual approach could lead Slate to success where some have failed and others are still trying.
Amgen and Eli Lilly advanced PACAP inhibitors to the clinic, only to see them fall short. Neuroscience drugs specialist Lundbeck remains in the hunt with bocunebart, an intravenously infused PACAP-blocking antibody that was part of its 2019 acquisition of Alder BioPharmaceuticals, whose main migraine asset was the now approved CGRP-inhibitor, Vyepti. During the American Headache Society Congress last month, Lundbeck reported Phase 2b data showing bocunebart led to a statistically significant reduction in headache days compared to a placebo.
The PACAP chase is also sparking startup activity. In June, Seattle-based Vedana Therapeutics launched with $46 million in Series A financing to support a pipeline of internally developed long-acting antibodies. The lead Vedana program targets PACAP; a second program is a bispecific antibody designed to target PACAP and CGRP. These drugs are being developed for subcutaneous dosing. Both Lundbeck and Vedana have former Alder employees, and so does Slate. Chief Medical Officer Roger Cady is a former Alder and Lundbeck executive.
Speaking during a Monday morning conference call, Slate’s Oakes said SLTE-1009 could offer better efficacy than other drugs that target PACAP. Slate also aims to offer less burdensome dosing. Whereas Lundbeck’s bocunebart is administered as an intravenous infusion every month, Slate’s drug is being developed for dosing as a subcutaneous injection every month, and perhaps even less frequently.
“PACAP blockade has shown encouraging clinical data in the prevention of migraine, and we believe the dual blockade of PACAP and VIP with a single monoclonal antibody offers the potential for enhanced efficacy relative to PACAP-only targeting therapeutics,” Oakes said. “SLTE-1009 was also engineered with half-life extension to enable subcutaneous dosing, with the potential to enable quarterly administration.”
Slate’s claims are based on preclinical research detailed in an investor presentation. The company is now preparing to build its case with clinical data. The biotech plans to bring SLTE-1009 through a Phase 1 test in healthy volunteers in Australia. Oakes said preliminary data are expected in mid-2027. Next, Slate plans to proceed to a Phase 2 dose-range finding study in migraine patients starting in the second half of next year.
The Slate pipeline also includes SLTE-2100, a preclinical bispecific antibody designed with one arm that targets PACAP/VIP and the other targeting CGRP. Slate expects to bring this drug into the clinic in the second half of 2027. The Slate pipeline also has another migraine program whose details remain confidential.
Slate’s reverse merger agreement with Fulcrum comes six months after the migraine drug biotech launched, backed by $130 million in Series A financing led by RA Capital, Forbion, and Foresite Capital. Those firms are also set to participate in the $245 million private placement, led by Frazier Life Sciences, that will happen concurrent with the merger’s close. Other participants in this private offering include Deep Track Capital, OrbiMed, RTW Investments, and Mingxin Capital.
Fulcrum’s former lead program was pociredir, an experimental therapy for sickle cell disease. Despite encouraging Phase 1b data in this blood disorder with few approved treatments, the FDA said it was concerned about cancer risks associated with drugs in pociredir’s class. Seeing no path forward for the small molecule, Fulcrum discontinued its development in June and said the company would explore strategic alternatives.
The Slate and Fulcrum business combination still needs the approval of shareholders from both companies. The deal is expected to close in the fourth quarter of this year. When that happens, pre-merger Slate stockholders will own about 55.9% of the combined company while the investors in the private placement will own about 39.1%. Pre-merger Fulcrum shareholders will own about 5% of the new Slate. The combined company is expected to trade on the Nasdaq under the stock symbol “SLTE.”
Photo by Flickr user Oregon DOT via a Creative Commons license
