Patent thicket asserted by Axsome against Apotex

Axsome Therapeutics has listed 94 patents in the Orange Book entry for Symbravo, a drug combination approved by the FDA in 2025 for treating migraines. Symbravo combines meloxicam and rizatriptan, two active ingredients first patented decades ago. Research by Generation Patient shows that 82 of the 94 patents listed in the Orange Book entry for Symbravo carry terminal disclaimers. Although most of the terminally disclaimed patents are interconnected through a complex linkage that traces back to a dosage form patent issued in 2017 and are therefore expected to expire in 2036 together with their earlier filed references, Axsome can assert each one of them individually against generic challengers.

Court documents show that Axsome has already asserted 75 patents from their thicket against Apotex, a generic manufacturer seeking to enter the market. That case was filed in September 2025 and is still ongoing as of May 2026. Apotex has argued that litigating all the asserted claims "will become a cost-prohibitive endeavor" instead of a "reasonable inquiry" into alleged infringement of legitimate patent rights. Our analysis of the terminal disclaimer linkages in this case shows that, under the ETHIC Act, Axsome would have been able to assert only five of those 75 patents.

Read more about how patent thickets increase costs and delay access for young adult patients.