The designation enables the fast-track development and review of Chugai Pharmaceuticals’ bispecific antibody candidate ACE910 as a new concept in the treatment of patients with haemophilia A, caused from the deficiency or functional disorder of coagulation factor VIII.
While a typical antibody has two antigen binding sites at its upper ends, a bispecific antibody is an artificially engineered antibody which has two different antigen binding sites allowing the binding of two different antigens.
“We have confirmed the bispecific antibody simultaneously binds factor IXa and factor X, exerting factor VIII-mimetic function to promote the blood coagulation reaction under the factor VIII lacking condition,” Chugai spokesperson Chisato Miyoshi told Biopharma-Reporter.com.
“Although we understand that the factor VIII replacement therapy have good efficacy, it requires multiple intravenous injections every week and there is a problem of developing anti-factor VIII neutralizing antibodies to eliminate the supplemented factor VIII agent as foreign substance.”
Chugai’s bispecific antibodies are made using the firm’s ART-Ig antibody engineering platform.
“ART-Ig consists of 3 technologies,” Miyoshi told us. “The identification of common light chain by [complementary-determining region] CDR shuffling, the purification of bispecific antibody by introducing differences in the charges of two heavy chains, and the expression of bispecific antibody through promoting heterodimerization by electrostatic steering.”
Bispecific Development
A number of biopharma firms have invested in, or struck up deals with companies which offer, bispecific antibody technologies.
Eli Lilly has investigated Genmab’s Duobody platform which works by merging two antibodies into one that can target two different targets, while Merck KGaA is in partnership with Sutro Biopharma.
Zheijan Hisun, meanwhile, is working with Ambrx, which uses its platform to manipulate the conjugation chemistries of the basic 20 amino acids in order to make bispecific antibodies.
Chugai’s parent company, Swiss Giant Roche, has its own CrossMAb technology to produce bispecific antibodies, but its technology is different from the ART-Ig.
The first, and so far only, bispecific antibody approved is Amgen’s Blincyto(Blinatumomab) which received the thumbs up from the US FDA last December through the Agency’s breakthrough therapy designation programme.