Takeda Pharmaceutical agreed to pay as much as $6 billion (?813 billion) for an experimental immune therapy from Nimbus Therapeutics ¡ª part of the Japanese drugmaker¡¯s hunt for promising new products.

Takeda will pay $4 billion upfront for the drug, which is called NDI-034858 and will be renamed TAK-279, the companies said Tuesday in a statement. Cambridge, Massachusetts-based Nimbus is also eligible for two additional milestone payments of $1 billion each if the drug reaches annual net sales of $4 billion and $5 billion, respectively.

Investors are looking for growth from Takeda since its $62 billion takeover of Shire five years ago. Chief Executive Officer Christophe Weber said the drug offers an opportunity to enhance its strategy beyond Entyvio: The ulcerative colitis treatment that generated about 15% of the company¡¯s revenue for the year that ended in March.

The Nimbus drug inhibits an immune-related protein called tyrosine kinase and recently yielded positive results in mid-stage studies of moderate-to-severe plaque psoriasis. It¡¯s expected to enter final-stage studies next year, according to the statement.

Evercore Group is acting as Takeda¡¯s financial adviser for the deal.