Authored by Karl Simpson
Earlier this month, as I gathered with prominent pharmaceutical leaders to discuss the challenges and opportunities of orphan drugs at the World Orphan Drug Congress in Washington, up the road was the Annual Meeting of the American Association for Cancer Research (AACR). At this meeting there were a number of companies presenting their latest developments in Antibody Drug Conjugates, including a very exciting company in the ADC market, Mersana Therapeutics. The company, founded by PureTech Ventures and some academics, has since attracted some other significant investors such as Fidelity Biosciences, Pfizer Venture Fund and NEA (New Enterprise Associates), who led the $27m series A round last year, the first placement from their new $2.6bn fund. Mersana now counts NEA’s General Partner David Mott among its board members as he now serves as Chairman.
Antibody Drug Conjugates are hot right now, attracting lots of interest after several companies have enjoyed great successes in this area of the antibody market, namely Seattle Genetics and Immunogen. Earlier this year Roche’s TDM-1 also got a green light from the regulator which has further stoked the ADC fire.
Mersana has a stellar line up of investors and so it not new to a bit of publicity. However, having already secured a $270m collaboration with Endo Pharmaceuticals for its ADC platform, Fleximer®. In Washington D.C, a the AACR meeting, Mersana were presenting a poster detailing that its technology, which has previously been applied to create lysine-based ADCs, can also be expanded to create cysteine-based ADCs. The data show that conjugation of Mersana’s Fleximer polymer via cysteines in the antibody hinge region overcomes the destabilization of the antibody which has been reported with conventional, direct drug-cysteine linked ADCs. The stabilization with the Fleximer conjugation approach enhances the advantages of Mersana’s polymer approach to ADCs, which include significantly higher capacity for drug payload, superior payload flexibility and improved physicochemical properties. In this research, the benefits were shown in Her-2 expressing cell lines and preclinical models.
Timothy B. Lowinger, Chief Scientific Officer of Mersana says “These data demonstrate that the scope of our conjugation technology can also be expanded to create novel, highly stable cysteine-based ADCs that are highly active, selective and well-tolerated in preclinical tumor models.”
Mersana has already been trumpeted as one to watch in the Fierce Biotech 15, this new data on top of developments with the company in 2012 only serve to build interest in this exciting company in the burgeoning biotech cluster of Cambridge, Massachusetts. It is also further evidence that the future of ADCs is looking good.