The Japanese drugmaker will pay that upfront to become Alnylam’s strategic partner for five years to use RNA interference, which offers a way to turn specific genes on and off, to develop treatments for cancer and metabolic disease.

Under terms of the agreement, Takeda will be the only Asian company with the right of first negotiation to develop and commercialize Alnylam programs for the Asian market. Alnylam will have the option to co-develop and co-commercialize Takeda’s linked programs in the US on a 50-50 basis, according to a statement. Takeda will also pay $50 million for short-term technology transfers.

The drugmakers say the partnership could potentially be worth as much as $1 billion, depending on the future success of any treatments that finally make it to market. Finding a way to turn off a gene that triggers disease is the sort of thing that attracts biotechs and drugmakers, such as Merck, which paid $1 billion to buy Sirna Therapeutics two years ago.