Tarsus Pharmaceuticals entered into a definitive agreement to acquire Alkeus Pharmaceuticals, in a deal built around gildeuretinol (Alk-001), an investigational once-daily oral therapy for Stargardt disease.

The upfront consideration of the acquistion is approximately $450 million, and is made up of $270 million in cash and $180 million in Tarsus common stock, with the stock priced at $61.38 per share at closing.¹ As part of the deal, Alkeus stockholders are eligible for up to $350 million in milestone payments tied to regulatory approval and first commercial sale, along with low single digit tiered descending royalties on gildeuretinol net sales.¹

The boards of both companies and Alkeus stockholders have approved the transaction, which is expected to close in 2026 pending expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act and other customary closing conditions.¹ Closing is not contingent on any financing.

What does gildeuretinol do?

Gildeuretinol is a new molecular entity designed to reduce the accumulation of toxic vitamin A dimers while preserving the normal visual cycle.¹ By limiting the buildup of these harmful byproducts, the therapy is intended to slow retinal damage and help preserve vision longer in patients with Stargardt disease.

What has the clinical data shown so far?

In the Tease-1 study, which evaluated 50 patients with advanced Stargardt disease marked by well-delineated atrophic lesions at baseline, treatment demonstrated a 29.5% slower untransformed, annualized growth rate of atrophic lesions compared with the untreated arm (placebo plus natural history), a result that reached statistical significance.¹ In the Tease-2 study, which evaluated 79 patients with reduced retinal sensitivity but without atrophic lesions at baseline, patients treated with gildeuretinol were 87% less likely to experience a significant loss in low light visual acuity, defined as a two-line decrease, compared with placebo.¹

Across more than 400 patients evaluated to date, some treated for over seven years, no treatment-related effects on night vision, dark adaptation or color vision have been reported, providing what the companies describe as meaningful tolerability experience for a potential chronic therapy.²

The data from the two previous studies informed the design of Northstar, the ongoing Phase III trial expected to enroll approximately 230 patients.² Its primary endpoint measures the rate of retinal atrophic lesion growth over 24 months, with a secondary endpoint assessing change in low light visual acuity.² The trial design was agreed to by FDA and the European Medicines Agency, and topline data are expected in the second half of 2029.²

How does the deal fit Tarsus' strategy?

"From the beginning, our strategy has been to build a leading eye care company by identifying significant diseases where patients have been starving for innovation and bringing forward medicines with the potential to change the standard of care," said Bobby Azamian, M.D., Ph.D., chief executive officer and chairman of Tarsus. "We believe gildeuretinol has the potential to be a transformational medicine for Stargardt disease and complements the retina capabilities we are already building through IRX-101. We also have tremendous respect for the Alkeus team and the exceptional work they have done to identify and bring forward an optimal asset to potentially address this blinding disease."

The acquisition is expected to expand Tarsus' presence in retina, building on the capabilities established through its acquisition of iRenix Medical, and adds a differentiated Phase III program addressing Stargardt disease.

Sources

1. Tarsus Pharmaceuticals to Acquire Alkeus Pharmaceuticals and Advance Eye Care Leadership Position Tarsus Pharmaceuticals August 6, 2026, https://www.globenewswire.com/news-release/2026/08/06/3340125/0/en/tarsus-pharmaceuticals-to-acquire-alkeus-pharmaceuticals-and-advance-eye-care-leadership-position.html
2. Study of ALK-001 on the Progression of Stargardt Disease (NORTHSTAR) National Library of Medicine July 28, 2026, https://clinicaltrials.gov/study/NCT07419334