The naive question first: if a drug is just a protein, why can't another company copy it exactly the way generic pill-makers copy aspirin? Because a small-molecule drug is a precise, easily reproduced chemical, while an antibody is an enormous protein grown in living cells. You can make something highly similar — a biosimilar — but "identical" is essentially impossible. That gap is the entire commercial story.
Start with what an antibody does. Think of it like a precision-guided grabber: your immune system naturally makes antibodies that latch onto specific threats. Drugmakers borrow the design, engineering an antibody to latch onto one chosen target. In retinal disease, that target is VEGF, the protein that triggers the leaky vessels behind vision loss. Block VEGF and you slow the disease.
Now the copy problem. When the original molecule's patents expire, competitors can sell a biosimilar — close enough to work, but legally and physically not the same. "Close enough" has to be proven in its own trials, which is why biosimilars are slower and costlier to bring than chemical generics. And crucially, a biosimilar of the molecule doesn't automatically clear every surrounding patent.
The anti-VEGF patent record makes the crowding vivid. Regeneron holds delivery-device IP like US12649031B2 (pre-filled syringes that reduce eye inflammation). Novartis holds US12649781B2 on treating diabetic retinopathy with its antibody brolucizumab. Kodiak Sciences holds US12643958B2 on treating eye disorders. Same target, multiple companies, each fencing off its own corner.
Here's the "so what." For an antibody franchise, the molecule is only the first patent. Around it sit claims on formulation, dosing schedule, and the injection device — and those can outlast the molecule's core protection. A biosimilar maker copying the active protein may still run into the patents on how it's delivered. That's why, in the previous decade's biosimilar wave, copies arrived later and captured less share than skeptics expected.
So when you read that a biosimilar is "coming" for a big antibody drug, translate it carefully. It means a near-copy of the molecule can compete — but the original maker has usually patented a ring of improvements around it. The anti-VEGF grants are a live map of that ring being built, one delivery-and-dosing patent at a time.