The popular framing of the GLP-1 wars is Lilly versus Novo Nordisk. The 2021 patent facet says the IP reality was always more crowded than the marketing duel - a field of peptide engineers staking overlapping claims across the incretin receptors.
Aggregate the 2021 incretin grants by assignee and the spread is striking: Bristol-Myers Squibb, Hanmi, Zealand Pharma, Sanofi, Amgen, Pfizer, and Merck all appear, alongside Novo Nordisk itself. Representative grants run from Hanmi's triple-agonist conjugate US10981967B2 to Zealand's US11111285B2 ("Glucagon-GLP-1-GIP triple agonist compounds") to Sanofi's GLP-1/glucagon dual-agonist conjugate US11141489B2.
The CPC clustering is tight and revealing: C07K 14/605 (glucagon-family peptides) and A61K 38/26 (GLP-1 medicinal preparations) recur across nearly every owner, with A61K 47/60 (conjugation) and A61P 3/04 / A61P 3/10 (anti-obesity / antidiabetic) layered on. When one CPC pair lights up across a dozen unrelated assignees, you are looking at a genuinely contested genus, not a single moat.
The strategic reading is that the inventive frontier had already fractured by 2021 into receptor combinations (dual, triple), agonism-versus-antagonism strategies, and conjugation chemistries for half-life. Each fracture is separately claimed, often by a different owner. The headline duopoly competes on commercialized products; the patent estate is a far wider battlefield.
For freedom-to-operate, the implication is concrete: a new metabolic-peptide program cannot clear the field by checking two companies' portfolios. It has to map the receptor-combination species and the conjugation chemistries across the whole crowd - Zealand, Hanmi, Sanofi, Amgen included - because any of them may hold the species the program reads on.