AstraZeneca has entered an agreement with Grunenthal for the global rights to Zomig (zolmitriptan) outside Japan.
Zomig is indicated for the acute treatment of migraines and cluster headaches, an area of medicine outside AstraZeneca's strategic focus. Grunenthal will pay AstraZeneca $200m upon completion.
AstraZeneca will also receive up to an additional $102m in future milestone payments.
Grunenthal will acquire the rights to Zomig in all markets outside Japan, including the US, where the rights were previously licensed to Impax Pharmaceuticals (Impax).
Impax will continue to market Zomig in the US.
AstraZeneca will continue to manufacture and supply the medicine to Grunenthal during a transition period. AstraZeneca executive vice-president, global product & portfolio strategy, Mark Mallon, said: "Grunenthal is an established partner with expertise in the treatment of pain.
"It is well placed to ensure patients continue to benefit from Zomig, and to extend the commercial potential of the medicine through its dedicated salesforce."