Mersana Therapeutics Inc. is getting $100 million up front in an option deal with GSK plc for preclinical-stage antibody-drug conjugate (ADC) XMT-2056, which could bring up to $1.36 billion more in an option exercise payment, development, regulatory and commercial milestones. It’s the second potential $1 billion-plus ADC deal for Cambridge, Mass.-based Mersana in 2022 and the first for its Immunosynthen platform, which uses a STING agonist payload specifically designed for ADCs.
Despite three mammoth deals signed for antibody-drug conjugates, the BioWorld Cancer Index (BCI), which ended last year down 36%, has fallen another 35% in the early months of 2022. It is a much sharper decline than that seen with the Nasdaq Biotechnology Index and the Dow Jones Industrial Average, which are down 18% and 7.5%, respectively.
Mersana Therapeutics Inc. has signed a potential billion-dollar agreement with Johnson & Johnson’s Janssen Biotech Inc. to research and develop antibody-drug conjugates (ADCs) for three cancer targets. Janssen will pay $40 million up front as well as more than $1 billion in potential milestone payments in a big day for ADCs, which saw Mersana’s other development partner, Synaffix BV, announce a tie-up with Macrogenics, Inc. in a deal worth up to $586 million.
The Netherlands-based Synaffix BV has expanded a deal focusing on its antibody-drug conjugate (ADC) linker tech with U.S. cancer biotech Mersana Therapeutics Inc., with the revised contract potentially paying out more than $1 billion. Privately owned Synaffix is hoping to ride a wave of interest in ADC technology, which is finally coming of age more than two decades after the first drug of this type was approved.
Shares of antibody drug conjugate developer Mersana Therapeutics Inc. (NASDAQ:MRSN) fell 39.1% to $8.56 on Sept. 10 after the company disclosed a second death from pneumonitis in the ongoing phase I trial testing its antibody drug conjugate, upifitamab rilsodotin against tumor types likely to express the sodium-dependent phosphate transport protein NaPi2b, such as ovarian cancer.
Contrary to the broader markets, BioWorld’s Cancer Index is down by 22% this year, losing more than 7% throughout the month of July, despite oncology driving several high-money deals and accounting for 38%, the lion’s share, of financings. Both the Nasdaq Biotech Index and the Dow Jones Industrial Average are tracking similarly for the year, and are up by 13.2% and 15.2%, respectively, as of Aug. 10.
The importance of the stimulator of interferon genes (STING) pathway in orchestrating the body’s innate response to pathogenic, tumor or self-DNA in the cytoplasm has made it a hot target in immunology research and drug discovery, and several biopharma companies have started programs dedicated to that area, spanning infectious and inflammatory diseases as well as cancer. The second part of this feature examines the products undergoing preclinical development as well as the ones that are now in clinical testing.
