F-star shoots for the moon with massive $1.35B J&J biobucks deal for 5 bispecifics

F-star Therapeutics has lined up multiple partners and Big Pharma licensing deals since snagging the Fierce 15 in 2011, but the latest pact with Johnson & Johnson is the biggest yet. 

The deal includes a modest $17.5 million upfront for up to five F-star bispecific antibodies, with a backloaded $1.35 billion in biobucks on the line. J&J's pharma unit Janssen snags the exclusive worldwide license to research, develop and commercialize those assets directed at targets of its choice, F-star said Wednesday.

Shares of the dual-Cambridge biotech (Massachusetts and the U.K.) rose about 13% to $7.27 apiece as of 9:34 a.m. ET on Wednesday.

The latest deal adds to a lineup of Big Pharma names. F-Star inked a $12 million upfront, $300 million biobucks deal with AstraZeneca for stimulator of interferon genes (STING) inhibitor compounds in July. 

RELATED: AstraZeneca becomes latest Big Pharma to get caught in F-Star STING with $12M upfront deal

Others to knock on F-star's doors include Merck KGaA, which exercised a third immuno-oncology bispecific in April, Denali Therapeutics, Bristol Myers Squibb and AbbVie.

This time around, the biotech isn't delivering a STING to Janssen, but rather some alphabet soup in Fcab and mAb2.

Janssen is paying to access F-star's platform that enables substitutions in the Fc region, or tail, of a natural antibody. This technology creates two more distinct sites for antigens to bind to, which forms what the biotech dubs "Fcab building blocks." Those pieces are placed into a natural IgG antibody to sprout what F-star calls mAb2 bispecific antibodies.

These bispecifics aim to limit toxicity, immunogenicity risk and manufacturing concerns. The Fcab and mAb2 technology have 230 patents and another 150 pending approval.