select two more. Endo will finance all development, manufacturing, and commercialization of the projects. If all three targets are pursued, Mersana could receive up to $270 million in milestone payments, plus royalties on worldwide sales.
Metzger says Endo proved to be an ideal partner. “They’re a specialty pharmaceutical company with an ongoing discovery effort in oncology, and specifically in antibody drug conjugates,” he says. “They have a very interesting antibody they wanted to deploy and they needed a technology like ours to make it work. Their expertise and resources were important to us.”
Mersana will continue to pursue a two-pronged development plan—investing in its own molecules while partnering with more companies like Endo that are interested in ADCs, Metzger says. Mersana’s venture investors include PureTech Ventures, Fidelity Biosciences, Rho Ventures, and ProQuest Investments.
Mersana isn’t the only biotech company that’s working on new methods for attaching drug payloads to nanoparticles. Cambridge, MA-based Cerulean is currently in clinical trials with CRLX101, a drug made of nanoparticles that carry camptothecin to cancer cells. And a number of companies are working on ADCs, including Roche unit Genentech and Seattle Genetics, the latter of which has made a big market impact with brentuximab vedotin (Adcetris), an armed antibody that has been shown to significantly shrink tumors in Hodgkin’s disease and anaplastic large-cell lymphoma.
The folks at Mersana are neither surprised nor concerned about the competition. “Our technology is more diverse and flexible than other technologies,” Metzger contends. “We’re able to work with lots of different payloads that are either already available or are being developed. We think we’re introducing some key advantages that the field will come to appreciate as we collaborate with partners and advance our own programs.”
Lowinger says he expects early results from marketed drugs like Seattle Genetics’ ADC to fuel the enthusiasm for the armed-antibody approach. “You’re not prolonging someone’s life for two or three months but really seeing the tumor shrink away,” he says. “This is realizing the dream of the magic bullet.”
