Tarsus closes Alkeus acquisition, adding Phase 3 Stargardt drug

Tarsus Pharmaceuticals completed its acquisition of Alkeus Pharmaceuticals on Sept. 4, 2026, adding worldwide rights to investigational ALK-001 (gildeuretinol acetate), a once-daily oral late-stage candidate in Phase 3 NORTHSTAR for Stargardt disease. Previously announced Aug. 6 terms included about $450 million upfront.

Tarsus Pharmaceuticals completed its acquisition of privately held Alkeus Pharmaceuticals on Sept. 4, adding worldwide rights to ALK-001, an investigational oral drug in Phase 3 development for Stargardt disease. The close moves Tarsus beyond its commercial XDEMVY business into late-stage retinal drug development.

ALK-001, also known as gildeuretinol acetate, is a once-daily, new molecular entity designed to reduce the accumulation of toxic vitamin A dimers while preserving the normal visual cycle. It is being studied in the global NORTHSTAR Phase 3 trial, with topline data anticipated in 2029, according to Tarsus's Sept. 4 closing release.

Stargardt disease is a potentially blinding inherited retinal disease. Tarsus says there is no FDA-approved therapy for it. ALK-001 remains investigational; its FDA Breakthrough Therapy, Orphan Drug, Fast Track and Rare Pediatric Disease designations for Stargardt disease do not constitute approval.

The financial terms were disclosed in the Aug. 6 acquisition announcement. That announcement described approximately $450 million in upfront consideration, comprising approximately $270 million in cash and $180 million in Tarsus common stock, with the stock to be issued at closing priced at $61.38 per share. It also specified up to $350 million in milestones tied to potential regulatory approval and first commercial sale, plus low single-digit, tiered descending royalties on gildeuretinol net sales. Those figures are the previously announced terms, rather than new disclosures in the closing release.

Tarsus said the transaction closed after satisfaction of the customary closing conditions in the definitive merger agreement announced Aug. 6. With ownership settled, the next checkpoints are integration of Alkeus and execution of NORTHSTAR toward the 2029 topline readout. The acquisition adds a late-stage candidate; its clinical and regulatory outcomes remain ahead.