BioCentury, THE BERNSTEIN REPORT ON BIOBUSINESS Emerging Company Profile Coferon: By Michael Flanagan Senior Writer Rather than trying to make ever smaller molecules that retain activity against com- plex targets, Coferon Inc. Is using a bioorthogonal linker technology to de- liver two halves of a therapeutic that self- assemble on the target after gaining entry into a cell. The company was set to an- nounce the close of a $12 million series B round on Monday this week. Targeting intracellular protein-protein interactions requires walking a fine line — a therapeutic needs to be small enough to enter the cell but large enough to modulate the interface between two bulky proteins. One way to do so is to use macrocycles, which feature a ring structure adorned with functional subunits. These typically range in size from 500-2,000 Da., making them larger than most small molecules but smaller than biologics (see "Ito Materials," Al3 & "Mini-Macrocycle Marriage," A15). Coferon is taking a new approach that it hopes will allow for better potency and selectivity than agents like macrocycles because there will be less need to de- crease target coverage to optimize an agent's ADMET properties, according to Chairman and CEO Colin Goddard. It also should be amenable to a wider range of targets by allowing for delivery of larger post-assembly agents. The company's reversible covalent linker chemistry was invented together by groups at Weill Cornell Medical Insti- tute and Purdue University and is exclusively licensed to Coferon. The strategy is to take a therapeutic that is too bulky for oral delivery or cell permeability and split it into two smaller components. The technology first links the two chemi- cally synthesized monomers, which disso- ciate under physiological conditions in- side the body so that they are small enough to cross the cell membrane. Once inside the cell, the linker moieties engineered onto each monomer dimerize using