Mersana snaps up $270M cancer drug deal with Endo Pharma

Mersana Therapeutics has scored its second major collaboration deal. Endo Pharmaceuticals ($ENDP) has tapped Mersana to create antibody-drug conjugates against an undisclosed cancer target. And like almost all biotech collaborations nowadays, this one is laden with lots of potential dollars that the industry calls "biobucks."

Endo has agreed to pony up a mystery upfront fee to Cambridge, MA-based Mersana and, if Endo elects to expand the collaboration from one target to three, it could end up paying Mersana more than $270 million in potential payments, according to Mersana's release. There's no specific asset revealed in the companies' announcement, but Mersana is expected to combine Endo's antibodies with its own proprietary Fleximer technology and linkers for arming the antibody drugs with anti-cancer toxins.

Venture-backed Mersana can now count Endo along with its earlier pharma collaborator, Teva Pharmaceutical ($TEVA). Endo and Teva have bought into the potential for Mersana's platform to offer a new generation of antibody-drug conjugates, which combine the ability of antibodies to home in on tumor targets with the killer punch of anti-cancer toxins into one drug. Seattle Genetics ($SGEN) snagged its first FDA approval for a cancer drug of this sort called Adcetris last summer, and Roche ($RHBBY) is in the hunt with its late-stage drug in this class called T-DM1, which uses linker tech from ImmunoGen ($IMGN).

Mersana says its next-generation linker system boosts the amount of drug that can be packed onto an antibody and can be used with targeting agents other than antibodies, including antibody fragments. Whether this tech leads to a major drug won't be known for years, as none of the company's candidates have advanced beyond Phase Ib. It's also worth noting that none of the FDA-approved antibody drug conjugates to date have turned into big commercial successes.

- here's the release