$27M funding will help advance Mersana's ADC pipeline

Mersana Therapeutics has raised $27 million in a Series A-1 financing led by new investor New Enterprise Associates (NEA), and will use the money to continue development of its Fleximer antibody-drug conjugate (ADC) platform and other ADCs. This is the first biopharma investment from NEA's recently announced $2.6 billion NEA 14 fund.

Antibody-drug conjugates combine cancer targeting antibodies and active drugs, and Mersana claims that its Fleximer technology improves both the pharmacokinetics of the molecules and the quantity of active drug carried in each conjugate. Mersana's two lead Fleximer ADCs are in clinical trials. XMT-1001 is in a Phase I trial for small cell lung cancer and non-small cell lung cancer, and XMT-1107, licensed to Teva in a $334M deal, is in Phase I trials in advanced solid tumors.

ADCs are a hot topic in cancer; Seattle Genetics' ($SGEN) Advetris was approved in the U.S.A. in August 2011, and ImmunoGen and Genentech's trastuzumab emtansine (T-DM1) data featured at ASCO 2012. Mersana also is developing other ADCs, including under a $270M agreement with Endo Pharmaceuticals for an undisclosed cancer target.

Other investors included Pfizer Venture Investments, Fidelity Biosciences, ProQuest Investments, Rho Ventures and Harris and Harris Group. As part of the financing, Mersana gains the expertise of NEA general partner David Mott (former CEO of MedImmune) and Sara Nayeem, principal at NEA.

"Recent breakthroughs in antibody-drug conjugates led by Seattle Genetics, ImmunoGen, and Genentech have begun to deliver … With the validation of the antibody-drug conjugate field behind us and tremendous potential ahead, we believe Mersana is uniquely positioned to capitalize on the drug development opportunities and surging strategic interest in the ADC field," says Mott.

- read the press release