US-based pharmaceutical company Mersana Therapeutics has signed a strategic partnership agreement with its Japan-based peer Takeda Pharmaceutical that is potentially worth more than $800m.

Mersana will secure an upfront payment of $40m and another $20m once an investigational new drug application has been granted for the company’s lead drug candidate, XMT-1522, in the US. Takeda has also agreed to provide up to $20m in future funding rounds.

Mersana is eligible for more than $750m in milestone payments for the treatment,…