Bayer Is Running Out of Time With Eylea. Its Answer Is a $2.45 Billion Gamble on a Blindness Drug.
Bayer Is Running Out of Time With Eylea. Its Answer Is a $2.45 Billion Gamble on a Blindness Drug.
On June 14, 2027, four key formulation patents on one of the best-selling drugs in pharmaceutical history begin to expire. Bayer co-markets that drug — Eylea — with Regeneron, and together they generated combined 2024 sales of $8.04 billion, split between $4.385 billion for Regeneron in the U.S. and €3.11 billion internationally. The formulation patents expire in 2027; higher-dose and method-of-use patents extend certain protections to 2039, but the revenue cliff arrives first. This quarter, U.S. Eylea sales already slipped 10% year over year, to $941 million, as doctors and patients anticipate the generic wave. On Wednesday, Bayer bought its way off it, acquiring Perfuse Therapeutics for up to $2.45 billion — a deal that values PER-001 at roughly 8 times its Phase IIa data.
PER-001 is not another pressure-lowering eye drop. It is the first drug in a new class — an endothelin receptor antagonist — to show disease-modifying activity in a controlled glaucoma trial. Every other FDA-approved glaucoma drug works by lowering intraocular pressure. PER-001 does not touch pressure at all.
The science behind it is specific. In glaucoma patients, a molecule called endothelin-1 becomes overactive in the retina. Endothelin is one of the most potent vasoconstrictors the body produces — it makes blood vessels tighten and stay tight. In the eye, that means the small arteries feeding the optic nerve and retina stay clamped down, starving tissue that cannot survive without steady blood flow. That ischemia appears to be what drives the progressive vision loss glaucoma causes even in patients whose eye pressure is already controlled. PER-001 blocks the receptor — endothelin type A, found on vascular smooth muscle cells — that endothelin locks onto to do its damage. Block the receptor, and the vasoconstriction stops.
In a Phase IIa glaucoma trial, 37.5% of high-dose patients gained 7 or more decibels of vision in a pre-specified retinal region after six months, versus 0% in the control group — 8 to 14 times the natural rate of improvement on standard treatment. No patient in the treatment arm lost that much vision; 12.5% of controls did. In diabetic retinopathy, high-dose patients gained a mean of 0.9 decibels in low luminance contrast sensitivity at 20 weeks while controls worsened by 2.1 decibels — roughly a three-line difference on a standard eye chart.
"Neuroenhancement — improvement in the function of existing optic nerve tissue — in humans with glaucoma," is how Joel Schuman, professor of ophthalmology at Wills Eye Hospital, described the result in Perfuse's press release. It is a striking claim in a field where every approved drug has worked the same way for decades.
Glaucoma affects roughly 76 to 80 million people worldwide and is the leading cause of irreversible blindness. Diabetic retinopathy — PER-001's second indication — affects about 146 million people globally, with 25 million dealing with vision-threatening disease and 1.3 million blind. The market is large and the need for something beyond eye drops is real.
There is a meaningful caveat on the science. This is Phase IIa data — small and designed to signal whether the concept is worth pursuing. The company plans pivotal Phase IIb/3 trials in the second half of 2025, per Bayer's press release. If those fail, the whole thesis collapses. PER-001 also requires intravitreal injection — a needle into the eye, administered in a doctor's office — which limits its convenience advantage over daily drops. And Bayer has not done a meaningful biotech acquisition in years, per BioSpace, which means it is paying for optionality rather than near-term revenue.
The competitive field will be watching closely. The current standard of care for wet age-related macular degeneration and diabetic eye disease is anti-VEGF therapy — drugs like Eylea itself, Regeneron's Eylea HD, Roche's Vabysmo, and off-label Avastin — which block a different signaling molecule involved in abnormal blood vessel growth. No vascular-targeting ocular drug outside anti-VEGF has yet reached market approval. If PER-001 succeeds, it opens a new commercial category and will attract follow-on programs from every major ophthalmology player.
There is also a payer dimension that Bayer will not advertise. Today's approved glaucoma drugs are measured by intraocular pressure reduction — a surrogate endpoint. If PER-001 reaches approval with actual vision-gain data in its label, it would be the first disease-modifying eye drug with endpoints that reflect what patients care about — not a proxy, but real visual field improvement. That kind of label carries pricing power that a surrogate-measured drug cannot easily replicate, because payers cannot easily argue that a drug that demonstrably improves vision should be confined to a low formulary tier.
Perfuse's founder and CEO, Sevgi Gurkan, said in Bayer's press release that Bayer "has the scale and global resources to unlock the full potential of PER-001 to change the trajectory of human blindness." That is the language of someone handing off a project, not running it.
What Bayer has bought is time and a foothold. PER-001 is not going to replace Eylea. But if it becomes the first disease-modifying eye drug approved in a category with no current competitors, it does not have to.