Mersana Brings in $27M and New Investors NEA and Pfizer

Xconomy Boston — 

Cambridge, MA-based Mersana Therapeutics announced today it has raised $27 million in a Series A-1 financing. The company brought in new investors Pfizer Venture Investments and New Enterprise Associates (NEA). Existing investors Fidelity Biosciences, ProQuest Investments, Rho Ventures, and Harris and Harris Group also participated. Mersana had raised a total of more than $50 million in previous rounds and is recapitalizing with this round, a spokesperson says in an e-mail.

Mersana marks the first biotech investment for the recently announced $2.6 billion NEA 14 fund.

Mersana is working in a hot area of biotech known as antibody drug conjugates (ADCs), which are proteins that are linked to cancer-fighting toxins and designed to home in on tumor cells. The financing will be used to advance Mersana’s technology, called Fleximer, a biodegradable polymer used to create ADCs that remain stable in the bloodstream and then release their drug payload once they’re inside cancer cells. Fleximer was developed at Massachusetts General Hospital.

The biotech company has generated a bit of interest in its Fleximer platform this year. In March, Mersana formed a development deal with Chadds Ford, PA-based Endo Pharmaceuticals (NASDAQ: ENDP) that could be worth up to $270 million in milestone payments plus royalties.